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Kientega M, Clarkson CS, Traoré N, Hui TYJ, O'Loughlin S, Millogo AA, Epopa PS, Yao FA, Belem AMG, Brenas J, Miles A, Burt A, Diabaté A. Whole-genome sequencing of major malaria vectors reveals the evolution of new insecticide resistance variants in a longitudinal study in Burkina Faso. Malar J 2024; 23:280. [PMID: 39285410 PMCID: PMC11406867 DOI: 10.1186/s12936-024-05106-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Accepted: 09/08/2024] [Indexed: 09/19/2024] Open
Abstract
BACKGROUND Intensive deployment of insecticide based malaria vector control tools resulted in the rapid evolution of phenotypes resistant to these chemicals. Understanding this process at the genomic level is important for the deployment of successful vector control interventions. Therefore, longitudinal sampling followed by whole genome sequencing (WGS) is necessary to understand how these evolutionary processes evolve over time. This study investigated the change in genetic structure and the evolution of the insecticide resistance variants in natural populations of Anopheles gambiae over time and space from 2012 to 2017 in Burkina Faso. METHODS New genomic data have been generated from An. gambiae mosquitoes collected from three villages in the western part of Burkina Faso between 2012 and 2017. The samples were whole-genome sequenced and the data used in the An. gambiae 1000 genomes (Ag1000G) project as part of the Vector Observatory. Genomic data were analysed using the analysis pipeline previously designed by the Ag1000G project. RESULTS The results showed similar and consistent nucleotide diversity and negative Tajima's D between An. gambiae sensu stricto (s.s.) and Anopheles coluzzii. Principal component analysis (PCA) and the fixation index (FST) showed a clear genetic structure in the An. gambiae sensu lato (s.l.) species. Genome-wide FST and H12 scans identified genomic regions under divergent selection that may have implications in the adaptation to ecological changes. Novel voltage-gated sodium channel pyrethroid resistance target-site alleles (V402L, I1527T) were identified at increasing frequencies alongside the established alleles (Vgsc-L995F, Vgsc-L995S and N1570Y) within the An. gambiae s.l. POPULATIONS Organophosphate metabolic resistance markers were also identified, at increasing frequencies, within the An. gambiae s.s. populations from 2012 to 2017, including the SNP Ace1-G280S and its associated duplication. Variants simultaneously identified in the same vector populations raise concerns about the long-term efficacy of new generation bed nets and the recently organophosphate pirimiphos-methyl indoor residual spraying in Burkina Faso. CONCLUSION These findings highlighted the benefit of genomic surveillance of malaria vectors for the detection of new insecticide resistance variants, the monitoring of the existing resistance variants, and also to get insights into the evolutionary processes driving insecticide resistance.
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Affiliation(s)
- Mahamadi Kientega
- Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545, Bobo-Dioulasso 01, Burkina Faso.
- Université Nazi Boni, 01 BP 1091, Bobo-Dioulasso, Burkina Faso.
| | - Chris S Clarkson
- Vector Surveillance Programme, Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | - Nouhoun Traoré
- Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545, Bobo-Dioulasso 01, Burkina Faso
- Université Nazi Boni, 01 BP 1091, Bobo-Dioulasso, Burkina Faso
| | - Tin-Yu J Hui
- Department of Life Sciences, Imperial College London, Silwood Park, Ascot, SL5 7PY, UK
| | - Samantha O'Loughlin
- Department of Life Sciences, Imperial College London, Silwood Park, Ascot, SL5 7PY, UK
| | - Abdoul-Azize Millogo
- Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545, Bobo-Dioulasso 01, Burkina Faso
- Institut des Sciences des Sociétés, 03 BP 7047, Ouagadougou 03, Burkina Faso
| | - Patric Stephane Epopa
- Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545, Bobo-Dioulasso 01, Burkina Faso
| | - Franck A Yao
- Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545, Bobo-Dioulasso 01, Burkina Faso
| | | | - Jon Brenas
- Vector Surveillance Programme, Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | - Alistair Miles
- Vector Surveillance Programme, Genomic Surveillance Unit, Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | - Austin Burt
- Department of Life Sciences, Imperial College London, Silwood Park, Ascot, SL5 7PY, UK
| | - Abdoulaye Diabaté
- Institut de Recherche en Sciences de la Santé (IRSS), 01 BP 545, Bobo-Dioulasso 01, Burkina Faso.
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Golumbeanu M, Briët O, Champagne C, Lemant J, Winkel M, Zogo B, Gerhards M, Sinka M, Chitnis N, Penny M, Pothin E, Smith T. AnophelesModel: An R package to interface mosquito bionomics, human exposure and intervention effects with models of malaria intervention impact. PLoS Comput Biol 2024; 20:e1011609. [PMID: 39269993 PMCID: PMC11424000 DOI: 10.1371/journal.pcbi.1011609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 09/25/2024] [Accepted: 08/16/2024] [Indexed: 09/15/2024] Open
Abstract
In recent decades, field and semi-field studies of malaria transmission have gathered geographic-specific information about mosquito ecology, behaviour and their sensitivity to interventions. Mathematical models of malaria transmission can incorporate such data to infer the likely impact of vector control interventions and hence guide malaria control strategies in various geographies. To facilitate this process and make model predictions of intervention impact available for different geographical regions, we developed AnophelesModel. AnophelesModel is an online, open-access R package that quantifies the impact of vector control interventions depending on mosquito species and location-specific characteristics. In addition, it includes a previously published, comprehensive, curated database of field entomological data from over 50 Anopheles species, field data on mosquito and human behaviour, and estimates of vector control effectiveness. Using the input data, the package parameterizes a discrete-time, state transition model of the mosquito oviposition cycle and infers species-specific impacts of various interventions on vectorial capacity. In addition, it offers formatted outputs ready to use in downstream analyses and by other models of malaria transmission for accurate representation of the vector-specific components. Using AnophelesModel, we show how the key implications for intervention impact change for various vectors and locations. The package facilitates quantitative comparisons of likely intervention impacts in different geographical settings varying in vector compositions, and can thus guide towards more robust and efficient malaria control recommendations. The AnophelesModel R package is available under a GPL-3.0 license at https://github.com/SwissTPH/AnophelesModel.
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Affiliation(s)
- Monica Golumbeanu
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Olivier Briët
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Clara Champagne
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Jeanne Lemant
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Munir Winkel
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | | | - Maximilian Gerhards
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Marianne Sinka
- Department of Biology, University of Oxford, Oxford, United Kingdom
| | - Nakul Chitnis
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Melissa Penny
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
- University of Basel, Basel, Switzerland
- The Kids Research Institute Australia, Nedlands, WA, Australia
- Centre for Child Health Research, University of Western Australia, Crawley, WA, Australia
| | - Emilie Pothin
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Tom Smith
- Swiss Tropical and Public Health Institute (Swiss TPH), Allschwil, Switzerland
- University of Basel, Basel, Switzerland
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Mahenge HH, Muyaga LL, Nkya JD, Kafwenji AD, Mwalugelo YA, Kahamba NF, Ngowo HS, Kaindoa EW. Semi-field evaluation of aquatic predators for the control of Anopheles funestus in rural south-eastern Tanzania. Malar J 2024; 23:228. [PMID: 39090658 PMCID: PMC11295350 DOI: 10.1186/s12936-024-05055-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 07/24/2024] [Indexed: 08/04/2024] Open
Abstract
BACKGROUND Biological control is a promising alternative or complementary approach for controlling vector populations in response to the spread of insecticide resistance in malaria vectors. This study evaluated the efficacy of three selected potential predators on the density and fitness parameters of Anopheles funestus larvae in rural Tanzania. METHODS Common predator families Aeshnidae (dragonflies), Coenagrionidae (damselflies), and Notonectidae (backswimmers) and An. funestus group larvae were collected from natural aquatic habitats in rural south-eastern Tanzania. Predators were starved for 12-h while An. funestus larvae were given fish food before starting the experiment. Anopheles funestus larvae were placed into artificial habitats containing predators, exposing them to potential predation. The number of surviving An. funestus larvae were counted every 24-h. An emergence traps were placed at the top of artificial habitats to capture emerging mosquitoes. Emerged mosquitoes were monitored until they died. Female wings were measured and used as a proxy for body size. Generalized linear mixed models (GLMM) with binomial variates at 95% CI and Cox proportional hazard models were used to assess the proportion of dead mosquitoes and the daily survival determined. RESULTS There were significant differences in the number of emerged mosquitoes between the treatment and control groups (P < 0.001). Thus, all predator species played a significant role in reducing the density of An. funestus mosquitoes (P < 0.001). Furthermore, these predators had notable effects on the fitness parameters and survival of emerged mosquitoes (P < 0.001). Among the three predators studied, Coenagrionidae (damselflies) were most efficient followed by Notonectidae (backswimmers), with Aeshnidae (dragonflies) being the least efficient. CONCLUSION Selected aquatic predators have the potential to reduce the survival and density of An. funestus larvae. They might eventually be included within an integrated malaria vector control strategy, ultimately leading to a reduction in malaria transmission.
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Affiliation(s)
- Herieth H Mahenge
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania.
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, Tengeru, Arusha, United Republic of Tanzania.
| | - Letus L Muyaga
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Joel D Nkya
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
| | - Andrew D Kafwenji
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
| | - Yohana A Mwalugelo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- Department of Biomedical Sciences, Jaramogi Oginga Odinga University of Science and Technology, P. O Box 210-40601, Bondo, Kenya
| | - Najat F Kahamba
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Halfan S Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Emmanuel W Kaindoa
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, Tengeru, Arusha, United Republic of Tanzania
- Faculty of Health Sciences, School of Pathology, The Centre for Emerging Zoonotic and Parasitic Diseases, Wits Research Institute for Malaria, National Institute for Communicable Diseases, University of the Witwatersrand, Johannesburg, South Africa
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Mwalugelo YA, Mponzi WP, Muyaga LL, Mahenge HH, Katusi GC, Muhonja F, Omondi D, Ochieng AO, Kaindoa EW, Amimo FA. Livestock keeping, mosquitoes and community viewpoints: a mixed methods assessment of relationships between livestock management, malaria vector biting risk and community perspectives in rural Tanzania. Malar J 2024; 23:213. [PMID: 39020392 PMCID: PMC11253484 DOI: 10.1186/s12936-024-05039-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 07/09/2024] [Indexed: 07/19/2024] Open
Abstract
BACKGROUND Livestock keeping is one of the potential factors related to malaria transmission. To date, the impact of livestock keeping on malaria transmission remains inconclusive, as some studies suggest a zooprophylactic effect while others indicate a zoopotentiation effect. This study assessed the impact of livestock management on malaria transmission risks in rural Tanzania. Additionally, the study explored the knowledge and perceptions of residents about the relationships between livestock keeping and malaria transmission risks in a selected village. METHODS In a longitudinal entomological study in Minepa village, South Eastern Tanzania, 40 households were randomly selected (20 with livestock, 20 without). Weekly mosquito collection was performed from January to April 2023. Indoor and outdoor collections used CDC-Light traps, Prokopack aspirators, human-baited double-net traps, and resting buckets. A subsample of mosquitoes was analysed using PCR and ELISA for mosquito species identification and blood meal detection. Livestock's impact on mosquito density was assessed using negative binomial GLMMs. Additionally, in-depth interviews explored community knowledge and perceptions of the relationship between livestock keeping and malaria transmission risks. RESULTS A total of 48,677 female Anopheles mosquitoes were collected. Out of these, 89% were Anopheles gambiae sensu lato (s.l.) while other species were Anopheles funestus s.l., Anopheles pharoensis, Anopheles coustani, and Anopheles squamosus. The findings revealed a statistically significant increase in the overall number of An. gambiae s.l. outdoors (RR = 1.181, 95%CI 1.050-1.862, p = 0.043). Also, there was an increase of the mean number of An. funestus s.l. mosquitoes collected in households with livestock indoors (RR = 2.866, 95%CI: 1.471-5.582, p = 0.002) and outdoors (RR = 1.579,95%CI 1.080-2.865, p = 0.023). The human blood index of Anopheles arabiensis mosquitoes from houses with livestock was less than those without livestock (OR = 0.149, 95%CI 0.110-0.178, p < 0.001). The majority of participants in the in-depth interviews reported a perceived high density of mosquitoes in houses with livestock compared to houses without livestock. CONCLUSION Despite the potential for zooprophylaxis, this study indicates a higher malaria transmission risk in livestock-keeping communities. It is crucial to prioritize and implement targeted interventions to control vector populations within these communities. Furthermore, it is important to enhance community education and awareness regarding covariates such as livestock that influence malaria transmission.
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Affiliation(s)
- Yohana A Mwalugelo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania.
- Department of Biomedical Sciences, Jaramogi Oginga Odinga University of Science and Technology, P. O. Box 210, Bondo, 40601, Kenya.
| | - Winifrida P Mponzi
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
| | - Letus L Muyaga
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Herieth H Mahenge
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- The Nelson Mandela, African Institution of Science and Technology, School of Life Sciences and BioEngineering, Tengeru, Arusha, United Republic of Tanzania
| | - Godfrey C Katusi
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
| | - Faith Muhonja
- School of Public Health, Amref International University, P.O. Box 27691-00506, Nairobi, Kenya
| | - Dickens Omondi
- Department of Biomedical Sciences, Jaramogi Oginga Odinga University of Science and Technology, P. O. Box 210, Bondo, 40601, Kenya
| | - Alfred O Ochieng
- Department of Biological Sciences, Jaramogi Oginga Odinga University of Science and Technology, P.O. Box 210, Bondo, 40601, Kenya
| | - Emmanuel W Kaindoa
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- The Nelson Mandela, African Institution of Science and Technology, School of Life Sciences and BioEngineering, Tengeru, Arusha, United Republic of Tanzania
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Fred A Amimo
- Department of Biomedical Sciences, Jaramogi Oginga Odinga University of Science and Technology, P. O. Box 210, Bondo, 40601, Kenya
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Hardy A. New directions for malaria vector control using geography and geospatial analysis. ADVANCES IN PARASITOLOGY 2024; 125:1-52. [PMID: 39095110 DOI: 10.1016/bs.apar.2024.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
As we strive towards the ambitious goal of malaria elimination, we must embrace integrated strategies and interventions. Like many diseases, malaria is heterogeneously distributed. This inherent spatial component means that geography and geospatial data is likely to have an important role in malaria control strategies. For instance, focussing interventions in areas where malaria risk is highest is likely to provide more cost-effective malaria control programmes. Equally, many malaria vector control strategies, particularly interventions like larval source management, would benefit from accurate maps of malaria vector habitats - sources of water that are used for malarial mosquito oviposition and larval development. In many landscapes, particularly in rural areas, the formation and persistence of these habitats is controlled by geographical factors, notably those related to hydrology. This is especially true for malaria vector species like Anopheles funestsus that show a preference for more permanent, often naturally occurring water sources like small rivers and spring-fed ponds. Previous work has embraced geographical concepts, techniques, and geospatial data for studying malaria risk and vector habitats. But there is much to be learnt if we are to fully exploit what the broader geographical discipline can offer in terms of operational malaria control, particularly in the face of a changing climate. This chapter outlines potential new directions related to several geographical concepts, data sources and analytical approaches, including terrain analysis, satellite imagery, drone technology and field-based observations. These directions are discussed within the context of designing new protocols and procedures that could be readily deployed within malaria control programmes, particularly those within sub-Saharan Africa, with a particular focus on experiences in the Kilombero Valley and the Zanzibar Archipelago, United Republic of Tanzania.
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Affiliation(s)
- Andy Hardy
- Department of Geography and Earth Sciences, Aberystwyth University, Penglais Campus, Aberystwyth, United Kingdom.
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Mapua SA, Samb B, Nambunga IH, Mkandawile G, Bwanaly H, Kaindoa EW, Odero JO, Masalu JP, Kahamba NF, Hape EE, Govella NJ, Okumu FO, Tripet F. Entomological survey of sibling species in the Anopheles funestus group in Tanzania confirms the role of Anopheles parensis as a secondary malaria vector. Parasit Vectors 2024; 17:261. [PMID: 38886827 PMCID: PMC11181546 DOI: 10.1186/s13071-024-06348-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 06/10/2024] [Indexed: 06/20/2024] Open
Abstract
BACKGROUND Malaria transmission in Tanzania is driven by mosquitoes of the Anopheles gambiae complex and Anopheles funestus group. The latter includes An. funestus s.s., an anthropophilic vector, which is now strongly resistant to public health insecticides, and several sibling species, which remain largely understudied despite their potential as secondary vectors. This paper provides the initial results of a cross-country study of the species composition, distribution and malaria transmission potential of members of the Anopheles funestus group in Tanzania. METHODS Mosquitoes were collected inside homes in 12 regions across Tanzania between 2018 and 2022 using Centres for Disease Control and Prevention (CDC) light traps and Prokopack aspirators. Polymerase chain reaction (PCR) assays targeting the noncoding internal transcribed spacer 2 (ITS2) and 18S ribosomal DNA (18S rDNA) were used to identify sibling species in the An. funestus group and presence of Plasmodium infections, respectively. Where DNA fragments failed to amplify during PCR, we sequenced the ITS2 region to identify any polymorphisms. RESULTS The following sibling species of the An. funestus group were found across Tanzania: An. funestus s.s. (50.3%), An. parensis (11.4%), An. rivulorum (1.1%), An. leesoni (0.3%). Sequencing of the ITS2 region in the nonamplified samples showed that polymorphisms at the priming sites of standard species-specific primers obstructed PCR amplification, although the ITS2 sequences closely matched those of An. funestus s.s., barring these polymorphisms. Of the 914 samples tested for Plasmodium infections, 11 An. funestus s.s. (1.2%), and 2 An. parensis (0.2%) individuals were confirmed positive for P. falciparum. The highest malaria transmission intensities [entomological inoculation rate (EIR)] contributed by the Funestus group were in the north-western region [108.3 infectious bites/person/year (ib/p/y)] and the south-eastern region (72.2 ib/p/y). CONCLUSIONS Whereas An. funestus s.s. is the dominant malaria vector in the Funestus group in Tanzania, this survey confirms the occurrence of Plasmodium-infected An. parensis, an observation previously made in at least two other occasions in the country. The findings indicate the need to better understand the ecology and vectorial capacity of this and other secondary malaria vectors in the region to improve malaria control.
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Affiliation(s)
- Salum Abdallah Mapua
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania.
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Huxley Building, Keele, Staffordshire, ST5 5BG, UK.
| | - Badara Samb
- Laboratoire d'Écologie Vectorielle et Parasitaire, Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop de Dakar, 5005, Dakar-Fann, BP, Senegal
| | - Ismail Hassan Nambunga
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania
| | - Gustav Mkandawile
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania
| | - Hamis Bwanaly
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania
| | - Emmanuel Wilson Kaindoa
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania
| | - Joel Ouma Odero
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G61 1QH, UK
| | - John Paliga Masalu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania
| | - Najat Feruz Kahamba
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G61 1QH, UK
| | - Emmanuel Elirehema Hape
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Nicodem James Govella
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G61 1QH, UK
- School of Life Science and Bioengineering, The Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha, Tanzania
| | - Fredros Oketch Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Morogoro, Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G61 1QH, UK
- School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Life Science and Bioengineering, The Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha, Tanzania
| | - Frederic Tripet
- Swiss Tropical and Public Health Institute, Kreuzgasse 2, 4123, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
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Chaves LSM, Bergo ES, Bickersmith SA, Laporta GZ, Conn JE, Sallum MAM. Forest cover percentage drives the peak biting time of Nyssorhynchus darlingi (Diptera: Culicidae) in the Brazilian Amazon. Malar J 2024; 23:166. [PMID: 38807105 PMCID: PMC11131226 DOI: 10.1186/s12936-024-04984-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 05/14/2024] [Indexed: 05/30/2024] Open
Abstract
BACKGROUND Deforestation is an important driver of malaria dynamics, with a relevant impact on mosquito ecology, including larval habitat availability, blood-feeding behaviour, and peak biting time. The latter is one of several entomological metrics to evaluate vectorial capacity and effectiveness of disease control. This study aimed to test the effect of forest cover percentage on the peak biting time of Plasmodium-uninfected and infected Nyssorhynchus darlingi females. METHODS Mosquitoes were captured utilizing human landing catch (HLC) in the peridomestic habitat in field collections carried out in the wet, wet-dry transition, and dry seasons from 2014 to 2017 in areas with active malaria transmission in Amazonian Brazil. The study locations were in rural settlements in areas with the mean annual malaria parasite incidence (Annual Parasite Incidence, API ≥ 30). All Ny. darlingi females were tested for Plasmodium spp. infection using real time PCR technique. Forest cover percentage was calculated for each collection site using QGIS v. 2.8 and was categorized in three distinct deforestation scenarios: (1) degraded, < 30% forest cover, (2) intermediate, 30-70% forest cover, and (3) preserved, > 70% forest cover. RESULTS The highest number of uninfected female Ny. darlingi was found in degraded landscape-sites with forest cover < 30% in any peak biting time between 18:00 and 0:00. Partially degraded landscape-sites, with (30-70%) forest cover, showed the highest number of vivax-infected females, with a peak biting time of 21:00-23:00. The number of P. falciparum-infected mosquitoes was highest in preserved sites with > 70% forest cover, a peak biting at 19:00-20:00, and in sites with 30-70% forest cover at 22:00-23:00. CONCLUSIONS Results of this study show empirically that degraded landscapes favour uninfected Ny. darlingi with a peak biting time at dusk (18:00-19:00), whereas partially degraded landscapes affect the behaviour of Plasmodium-infected Ny. darlingi by shifting its peak biting time towards hours after dark (21:00-23:00). In preserved sites, Plasmodium-infected Ny. darlingi bite around dusk (18:00-19:00) and shortly after (19:00-20:00).
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Affiliation(s)
- Leonardo Suveges Moreira Chaves
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, Av. Dr. Arnaldo, 715 - Pacaembu, CEP, 01246-904, São Paulo, SP, Brasil
| | | | | | - Gabriel Z Laporta
- Graduate Program in Health Sciences, FMABC Medical School University Center, Santo André, SP, Brazil
| | - Jan E Conn
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
- Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, NY, USA
| | - Maria Anice Mureb Sallum
- Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, Av. Dr. Arnaldo, 715 - Pacaembu, CEP, 01246-904, São Paulo, SP, Brasil.
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Woldesenbet D, Tegegne Y, Semaw M, Abebe W, Barasa S, Wubetie M, Tamene E, Anteneh M, Yimer A, Wolde D. Malaria Prevalence and Risk Factors in Outpatients at Teda Health Center, Northwest Ethiopia: A Cross-Sectional Study. J Parasitol Res 2024; 2024:8919098. [PMID: 38774539 PMCID: PMC11108681 DOI: 10.1155/2024/8919098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 04/10/2024] [Accepted: 04/27/2024] [Indexed: 05/24/2024] Open
Abstract
Background Despite extensive efforts and achievements made in prevention and control, malaria is still a public health problem in Ethiopia. Currently, the case number has been climbing, even changing the epidemiology to the previously low-burden reporting locations. Therefore, our study is aimed at assessing malaria prevalence and associated risk factors in outpatients, Northwest Ethiopia. Methods A facility-based cross-sectional study was conducted among 318 malaria-suspected outpatients from October 22 to December 15, 2022, at Teda Health Center, Northwest Ethiopia. Sociodemographic characteristics and malaria risk factors were assessed by a face-to-face interview using a pretested questionnaire. Plasmodium parasites were detected by using microscopy on a blood film stained with 10% and 3% Giemsa stain. The data were analyzed using Statistical Package for Social Sciences software version 25, and statistical significance was reported at a p value < 0.05. Results Of the 318 study participants, 124 (39.0%; 95%CI = 33.6% - 44.6%) tested positive for Plasmodium infection. Plasmodium vivax, P. falciparum, and mixed infections were identified in 71 (57.3%), 47 (37.9%), and 6 (4.8%), respectively, among positive study participants. Individuals above the age of 15 (AOR = 2.704, 95% CI 1.370-5.336) were more likely to be infected with Plasmodium than under-five-year-old individuals. Rural residents (AOR = 2.56, 95% CI 1.281-5.098), those who sleep or work outside at night (AOR = 1.99, 95% CI 1.020-3.875), and individuals who did not use long-lasting insecticide-treated net (AOR = 3.26, 95% CI 1.633-6.499) and had a family member with a history of malaria (AOR = 2.902, 95%CI = 1.671 - 5.041) had higher odds of acquiring Plasmodium infection than their counterparts. Conclusion In our study area, malaria was a major health problem, with P. vivax being the dominant species. Multiple environmental and behavioural factors were associated with the infection acquisition. Therefore, urgent holistic intervention is required.
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Affiliation(s)
- Dagmawi Woldesenbet
- Department of Medical Laboratory Science, College of Medicine and Health Science, Wachemo University, Hossana, Ethiopia
| | - Yalewayker Tegegne
- Department of Medical Parasitology, School of Biomedical and Laboratory Science, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia
| | - Muluken Semaw
- Medical Laboratory Unit, Sanja General Hospital, Amhara National Regional State Health Bureau, Sanja, Ethiopia
| | - Wagaw Abebe
- Department of Medical Laboratory Science, College of Health Science, Woldia University, Woldia, Ethiopia
| | - Silesh Barasa
- Department of Medical Laboratory Science, College of Medicine and Health Science, Arba Minch University, Arba Minch, Ethiopia
| | - Menberu Wubetie
- Department of Medical Laboratory Science, College of Medicine and Health Science, Dire Dawa University, Dire Dawa, Ethiopia
| | - Elias Tamene
- Department of Medical Laboratory Science, College of Medicine and Health Science, Wachemo University, Hossana, Ethiopia
| | - Marshet Anteneh
- Bahir Dar Blood Bank, Amhara National Regional State Health Bureau, Bahir Dar, Ethiopia
| | - Aschalew Yimer
- Medical Laboratory Unit, Teda Health Center, Amhara National Regional State Health Bureau, Gondar, Ethiopia
| | - Deneke Wolde
- Department of Medical Laboratory Science, College of Medicine and Health Science, Wachemo University, Hossana, Ethiopia
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Minja EG, Mrimi EC, Mponzi WP, Mollel GJ, Lang C, Beckmann J, Gerber M, Pühse U, Long KZ, Masanja H, Okumu FO, Finda MF, Utzinger J. Prevalence and Determinants of Undernutrition in Schoolchildren in the Kilombero District, South-Eastern Tanzania. Trop Med Infect Dis 2024; 9:96. [PMID: 38787029 PMCID: PMC11125975 DOI: 10.3390/tropicalmed9050096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
Childhood undernutrition is a major issue in low- and middle-income countries, affecting the health, well-being, and educational outcomes of schoolchildren. This study aimed to assess the prevalence and associated factors of stunting, wasting, and underweight among schoolchildren in peri-urban areas in the south-eastern part of Tanzania. A cross-sectional study was conducted involving 930 children aged 6-12 years from four primary schools from July to August 2019. The WHO Anthro Survey Analyzer was employed to estimate the prevalence of stunting, wasting, and underweight, while logistic regression analyses examined sociodemographic background, malaria infection, anaemia, anthropometric measures, and dietary diversity score as potential factors. The prevalence of stunting, wasting, underweight, overweight, and obesity was 11.8%, 4.3%, 3.9%, 11.1%, and 2.0%, respectively. Overall, 1.5% of the children had malaria, as determined by rapid diagnostic tests, and 0.4% had severe anaemia. Univariate analysis indicated higher odds of undernutrition among children aged 9-12 compared to their younger peers. Stunting was more common among children with low and medium dietary diversity. Anaemia was found in 11.2% of schoolchildren, and severe anaemia was associated with wasting. Multivariate analysis revealed that age and low dietary diversity were significantly associated with undernutrition. These findings emphasise the need for school-based health and nutrition programmes targeting children beyond the age of 5 to improve their nutritional status and mitigate potential adverse effects on health, cognition, and academic achievement. Regular assessment of the nutritional status of schoolchildren is warranted.
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Affiliation(s)
- Elihaika G. Minja
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara P.O. Box 53, Tanzania; (E.C.M.); (W.P.M.); (G.J.M.); (H.M.); (F.O.O.); (M.F.F.)
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, CH-4123 Allschwil, Switzerland; (K.Z.L.); (J.U.)
- Faculty of Medicine, University of Basel, Petersplatz 1, CH-4003 Basel, Switzerland
| | - Emmanuel C. Mrimi
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara P.O. Box 53, Tanzania; (E.C.M.); (W.P.M.); (G.J.M.); (H.M.); (F.O.O.); (M.F.F.)
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, CH-4123 Allschwil, Switzerland; (K.Z.L.); (J.U.)
- Faculty of Medicine, University of Basel, Petersplatz 1, CH-4003 Basel, Switzerland
| | - Winfrida P. Mponzi
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara P.O. Box 53, Tanzania; (E.C.M.); (W.P.M.); (G.J.M.); (H.M.); (F.O.O.); (M.F.F.)
| | - Getrud J. Mollel
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara P.O. Box 53, Tanzania; (E.C.M.); (W.P.M.); (G.J.M.); (H.M.); (F.O.O.); (M.F.F.)
- Department of Pediatrics and Child Health, Muhimbili University of Health and Allied Sciences, Dar es Salaam P.O. Box 65001, Tanzania
| | - Christin Lang
- Department of Sport, Exercise and Health, University of Basel, Grosse Allee 6, CH-4052 Basel, Switzerland; (C.L.); (J.B.); (M.G.); (U.P.)
| | - Johanna Beckmann
- Department of Sport, Exercise and Health, University of Basel, Grosse Allee 6, CH-4052 Basel, Switzerland; (C.L.); (J.B.); (M.G.); (U.P.)
| | - Markus Gerber
- Department of Sport, Exercise and Health, University of Basel, Grosse Allee 6, CH-4052 Basel, Switzerland; (C.L.); (J.B.); (M.G.); (U.P.)
| | - Uwe Pühse
- Department of Sport, Exercise and Health, University of Basel, Grosse Allee 6, CH-4052 Basel, Switzerland; (C.L.); (J.B.); (M.G.); (U.P.)
| | - Kurt Z. Long
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, CH-4123 Allschwil, Switzerland; (K.Z.L.); (J.U.)
- Faculty of Medicine, University of Basel, Petersplatz 1, CH-4003 Basel, Switzerland
| | - Honorati Masanja
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara P.O. Box 53, Tanzania; (E.C.M.); (W.P.M.); (G.J.M.); (H.M.); (F.O.O.); (M.F.F.)
| | - Fredros O. Okumu
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara P.O. Box 53, Tanzania; (E.C.M.); (W.P.M.); (G.J.M.); (H.M.); (F.O.O.); (M.F.F.)
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow G12 8QQ, UK
- School of Life Science and Bioengineering, Nelson Mandela African Institution of Science & Technology, Arusha P.O. Box 447, Tanzania
| | - Marceline F. Finda
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara P.O. Box 53, Tanzania; (E.C.M.); (W.P.M.); (G.J.M.); (H.M.); (F.O.O.); (M.F.F.)
- School of Life Science and Bioengineering, Nelson Mandela African Institution of Science & Technology, Arusha P.O. Box 447, Tanzania
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Kreuzstrasse 2, CH-4123 Allschwil, Switzerland; (K.Z.L.); (J.U.)
- Faculty of Medicine, University of Basel, Petersplatz 1, CH-4003 Basel, Switzerland
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Giraldo D, McMeniman CJ. Quantifying Mosquito Host Preference. Cold Spring Harb Protoc 2024; 2024:107663. [PMID: 37612146 DOI: 10.1101/pdb.top107663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
The most dangerous mosquito species for human health are those that blood feed preferentially and frequently on humans (anthropophilic mosquitoes). These include prolific disease vectors such as the African malaria mosquito Anopheles gambiae and yellow fever mosquito Aedes aegypti The chemosensory basis for anthropophilic behavior exhibited by these disease vectors, as well as the factors that drive interindividual differences in human attractiveness to mosquitoes, remain largely uncharacterized. Here, we concisely review established methods to quantify mosquito interspecific and intraspecific host preference in the laboratory, as well as semi-field and field environments. Experimental variables for investigator consideration during assays of mosquito host preference across these settings are highlighted.
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Affiliation(s)
- Diego Giraldo
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA
| | - Conor J McMeniman
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Odufuwa OG, Bradley J, Ngonyani S, Mpelepele AB, Matanila I, Muganga JB, Bosselmann R, Skovmand O, Mboma ZM, Moore SJ. Time of exposure and assessment influence the mortality induced by insecticides against metabolic resistant mosquitoes. Parasit Vectors 2024; 17:103. [PMID: 38431631 PMCID: PMC10908098 DOI: 10.1186/s13071-024-06190-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/09/2024] [Indexed: 03/05/2024] Open
Abstract
BACKGROUND Increasing metabolic resistance in malaria vector mosquitoes resulted in the development of insecticide-treated nets (ITNs) with active ingredients (AI) that target them. Bioassays that accurately measure the mortality induced by these AIs on ITNs are needed. Mosquito metabolic enzyme expression follows a circadian rhythm. Thus, this study assessed (i) influence of the time of day of mosquito exposure and (ii) timing of assessment of mortality post exposure (24 and 72 h) to ITNs against vectors that are susceptible to pyrethroids and those with metabolic and knockdown resistance mechanisms. METHODS Two cone bioassay experiments were conducted following World Health Organization (WHO) guidelines. Firstly, on ITNs incorporated with 2 g AI/kg of deltamethrin (DM) alone, or combined with 8 g AI/kg piperonyl butoxide (PBO) synergist, during the day (9:00-14:00 h) and repeated in the evening (18:00-20:00 h). This was followed by a confirmatory experiment during the afternoon (12:00-14:00 h) and repeated in the night (22:00-24:00 h) using mosquitoes unexposed or pre-exposed to PBO for 1 h before exposure to DM ITNs. Each net piece was tested with a minimum of eight cones per time (N = 24). The outcome was mortality after 24 h (M24) or 72 h (M72) of holding. RESULTS The cone bioassays performed using metabolic resistant mosquitoes during the evening showed significantly lower M24 than those performed in the day for DM: odds ratio (OR) 0.14 [95% confidence interval (CI) 0.06-0.30, p < 0.0001] and DM PBO [OR 0.29 (95% CI 0.18-0.49, p < 0.0001). M72 was higher than M24 for metabolic resistant mosquitoes exposed to DM [OR 1.44 (95% CI 1.09-1.88), p = 0.009] and DM PBO [OR 1.82 (95% CI 1.42-2.34), p < 0.0001]. An influence of hour of experiment and time of assessment was not observed for mosquitoes that had knockdown resistance or that were pyrethroid-susceptible. CONCLUSIONS Time of day of experiment and hour of assessment of delayed mortality after exposure of mosquitoes are important considerations in evaluating insecticides that interact with mosquito metabolism to counter metabolic resistant mosquitoes. This is important when evaluating field-aged ITNs that may have lower concentrations of AI.
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Affiliation(s)
- Olukayode G Odufuwa
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania.
- Vector Biology Unit, Department of Epidemiology and Public Health, Swiss Tropical & Public Health Institute, Kreuzstrasse 2, Allschwill, 4123, Basel, Switzerland.
- Faculty of Science, University of Basel, Petersplatz 1, 4001, Basel, Switzerland.
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK.
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK
| | - Safina Ngonyani
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | - Ahmadi Bakari Mpelepele
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | - Isaya Matanila
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | - Joseph B Muganga
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
| | | | | | - Zawadi Mageni Mboma
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
- The Nelson Mandela African Institution of Science and Technology (NM-AIST), Tengeru, P.O. Box 447, Arusha, Tanzania
| | - Sarah Jane Moore
- Vector Control Product Testing Unit (VCPTU) Ifakara Health Institute, Environmental Health, and Ecological Sciences, P.O. Box 74, Bagamoyo, Tanzania
- Vector Biology Unit, Department of Epidemiology and Public Health, Swiss Tropical & Public Health Institute, Kreuzstrasse 2, Allschwill, 4123, Basel, Switzerland
- Faculty of Science, University of Basel, Petersplatz 1, 4001, Basel, Switzerland
- The Nelson Mandela African Institution of Science and Technology (NM-AIST), Tengeru, P.O. Box 447, Arusha, Tanzania
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Jupp D, Ayuandini S, Tobing F, Halim D, Kenangalem E, Sumiwi ME, Prameswari HD, Theodora M, Susanto H, Dewi RTP, Supriyanto D, Kurnia B, Shetye M, Ndoen E, Onishi Y. How using light touch immersion research revealed important insights into the lack of progress in malaria elimination in Eastern Indonesia. Malar J 2024; 23:59. [PMID: 38413921 PMCID: PMC10898039 DOI: 10.1186/s12936-024-04865-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 01/29/2024] [Indexed: 02/29/2024] Open
Abstract
BACKGROUND By 2022, the Government of Indonesia had successfully eliminated malaria in 389 out of 514 districts but continues to face a challenge in Eastern Indonesia where 95% of the total 2021 malaria cases were reported from Papua, West Papua and Nusa Tenggara Timur provinces. There is an increased recognition that malaria elimination will require a better understanding of the human behavioural factors hindering malaria prevention and treatment, informed by local context and local practice. METHODS This research used a light-touch immersion research approach. Field researchers lived in communities over several days to gather data through informal conversations, group-based discussions using visual tools, participant observation and direct experience. The study was conducted in four high malaria endemic areas in Papua, West Papua, and Sumba Islands in Nusa Tenggara Timur. RESULTS The research highlights how people's perception of malaria has changed since the introduction of effective treatment which, in turn, has contributed to a casual attitude towards early testing and adherence to malaria treatment. It also confirms that people rarely accept there is a link between mosquitoes and malaria based on their experience but nevertheless take precautions against the annoyance of mosquitoes. There is widespread recognition that babies and small children, elderly and incomers are more likely to be seriously affected by malaria and separately, more troubled by mosquitoes than indigenous adult populations. This is primarily explained by acclimatization and strong immune systems among the latter. CONCLUSIONS Using immersion research enabled behaviour research within a naturalistic setting, which in turn enabled experiential-led analysis of findings and revealed previously unrecognized insights into attitudes towards malaria in Eastern Indonesia. The research provides explanations of people's lack of motivation to consistently use bed nets, seek early diagnosis or complete courses of treatment. The felt concern for the wellbeing of vulnerable populations highlighted during light touch immersion provides an entry point for future social behaviour change communication interventions. Rather than trying to explain transmission to people who deny this connection, the research concludes that it may be better to focus separately on the two problems of malaria and mosquitoes (especially for vulnerable groups) thereby resonating with local people's own experience and felt concerns.
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Limwagu AJ, Msugupakulya BJ, Kilalangongono MM, Mwalugelo YA, Okumu FO, Lyimo IN, Ngasala BE. Evaluation of the DN-Mini (miniaturized double net) trap for sampling host-seeking Anopheles mosquitoes in malaria-endemic villages of southern Tanzania. PLoS One 2024; 19:e0294192. [PMID: 38354118 PMCID: PMC10866531 DOI: 10.1371/journal.pone.0294192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 10/26/2023] [Indexed: 02/16/2024] Open
Abstract
BACKGROUND Surveillance of malaria vectors is crucial for assessing the transmission risk and impact of control measures. Human landing catches (HLC) directly estimate the biting rates but raise ethical concerns due to the exposure of volunteers to mosquito-borne pathogens. A common alternative is the CDC-light trap, which is effective for catching host-seeking mosquitoes indoors but not outdoors. New, exposure-free methods are needed for sampling mosquitoes indoors and outdoors in ways that reflect their natural risk profiles. The aim of this study was therefore to evaluate the efficacy of the miniaturized double net trap (DN-Mini) for sampling host-seeking mosquitoes in south-eastern Tanzania, where malaria transmission is dominated by Anopheles funestus. METHODS Adult mosquitoes were collected from 222 randomly selected houses across three villages (74 per village) in Ulanga district, south-eastern Tanzania, using the DN-Mini traps, CDC-Light traps, and Prokopack aspirators. First, we compared CDC-light and DN-Mini traps for collecting indoor host-seeking mosquitoes, while Prokopack aspirators were used for indoor-resting mosquitoes. Second, we deployed the DN-Mini and Prokopack aspirators to collect host-seeking and resting mosquitoes indoors and outdoors. Generalized linear mixed models (GLMM) with a negative binomial distribution were used to compare the effectiveness of the traps for catching different mosquito species. RESULTS The DN-Mini was 1.53 times more efficient in collecting An. funestus indoors (RR = 1.53, 95% CI: 1.190-1.98) compared to the CDC-Light trap. However, for Anopheles arabiensis, the DN-Mini caught only 0.32 times as many mosquitoes indoors as the CDC-Light traps (RR = 0.32, 95% CI: 0.183-0.567). Both An. funestus and An. arabiensis were found to be more abundant indoors than outdoors when collected using the DN-Mini trap. Similarly, the Prokopack aspirator was greater indoors than outdoors for both An. funestus and An. arabiensis. CONCLUSION The DN-Mini outperformed the CDC-light trap in sampling the dominant malaria vector, An. funestus species, but was less effective in capturing An. arabiensis, and for both vector species, the biting risk was greater indoors than outdoors when measured using the DN-Mini trap. These findings highlight the importance of selecting appropriate trapping methods based on mosquito species and behaviors.
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Affiliation(s)
- Alex J. Limwagu
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Morogoro, Tanzania
- Parasitology and Medical Entomology Department, Muhimbili University of Health and Allied Science, Dar es Salaam, Tanzania
| | - Betwel J. Msugupakulya
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Morogoro, Tanzania
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Masoud M. Kilalangongono
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Morogoro, Tanzania
| | - Yohana A. Mwalugelo
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Morogoro, Tanzania
- Department of Biomedical Sciences, Jaramogi Oginga Odinga University of Science and Technology, Bondo, Kenya
| | - Fredros O. Okumu
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Morogoro, Tanzania
- School of Life Science and Bioengineering, Nelson Mandela Africa Institution of Science and Technology, Arusha, Tanzania
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Issa N. Lyimo
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Morogoro, Tanzania
- School of Life Science and Bioengineering, Nelson Mandela Africa Institution of Science and Technology, Arusha, Tanzania
| | - Billy E. Ngasala
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Morogoro, Tanzania
- Parasitology and Medical Entomology Department, Muhimbili University of Health and Allied Science, Dar es Salaam, Tanzania
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Kahamba NF, Okumu FO, Jumanne M, Kifungo K, Odero JO, Baldini F, Ferguson HM, Nelli L. Geospatial modelling of dry season habitats of the malaria vector, Anopheles funestus, in south-eastern Tanzania. Parasit Vectors 2024; 17:38. [PMID: 38287419 PMCID: PMC10825994 DOI: 10.1186/s13071-024-06119-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 01/03/2024] [Indexed: 01/31/2024] Open
Abstract
BACKGROUND Anopheles funestus is a major malaria vector in Eastern and Southern Africa and is currently the dominant malaria-transmitting vector in many parts of Tanzania. Previous research has identified its preference for specific aquatic habitats, especially those that persist in dry months. This observation suggests the potential for targeted control through precise habitat mapping and characterization. In this study, we investigated the influence of habitat characteristics, land cover and human population densities on An. funestus distribution during dry seasons. Based on the results, we developed a habitat suitability model for this vector species in south-eastern Tanzania. METHODS Eighteen villages in south-eastern Tanzania were surveyed during the dry season from September-December 2021. Water bodies were systematically inspected for mosquito larvae and characterized by their physico-chemical characteristics and surrounding environmental features. A generalized linear model was used to assess the presence of An. funestus larvae as a function of the physico-chemical characteristics, land use and human population densities. The results obtained from this model were used to generate spatially explicit predictions of habitat suitability in the study districts. RESULTS Of the 1466 aquatic habitats surveyed, 440 were positive for An. funestus, with river streams having the highest positivity (74%; n = 322) followed by ground pools (15%; n = 67). The final model had an 83% accuracy in predicting positive An. funestus habitats, with the most important characteristics being permanent waters, clear waters with or without vegetation or movement and shading over the habitats. There was also a positive association of An. funestus presence with forested areas and a negative association with built-up areas. Human population densities had no influence on An. funestus distribution. CONCLUSIONS The results of this study underscore the crucial role of both the specific habitat characteristics and key environmental factors, notably land cover, in the distribution of An. funestus. In this study area, An. funestus predominantly inhabits river streams and ground pools, with a preference for clear, perennial waters with shading. The strong positive association with more pristine environments with tree covers and the negative association with built-up areas underscore the importance of ecological transitions in vector distribution and malaria transmission risk. Such spatially explicit predictions could enable more precise interventions, particularly larval source management, to accelerate malaria control.
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Affiliation(s)
- Najat F Kahamba
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania.
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK.
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
- School of Public Health, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Life Science and Biotechnology, Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha, Tanzania
| | - Mohammed Jumanne
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
| | - Khamisi Kifungo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
| | - Joel O Odero
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Francesco Baldini
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Heather M Ferguson
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Luca Nelli
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK.
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Msugupakulya BJ, Ngajuma SK, Ngayambwa AN, Kidwanga BE, Mpasuka IR, Selvaraj P, Wilson AL, Okumu FO. Influence of larval growth and habitat shading on retreatment frequencies of biolarvicides against malaria vectors. Sci Rep 2024; 14:1002. [PMID: 38200070 PMCID: PMC10781946 DOI: 10.1038/s41598-024-51152-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 01/01/2024] [Indexed: 01/12/2024] Open
Abstract
Effective larviciding for malaria control requires detailed studies of larvicide efficacies, aquatic habitat characteristics, and life history traits of target vectors. Mosquitoes with brief larval phases present narrower timeframes for biolarvicidal effects than mosquitoes with extended periods. We evaluated two biolarvicides, VectoBac (Bacillus thuringiensis israelensis (Bti)) and VectoMax (Bti and Bacillus sphaericus) against Anopheles funestus and Anopheles arabiensis in shaded and unshaded habitats; and explored how larval development might influence retreatment intervals. These tests were done in semi-natural habitats using field-collected larvae, with untreated habitats as controls. Additionally, larval development was assessed in semi-natural and natural habitats in rural Tanzania, by sampling daily and recording larval developmental stages. Both biolarvicides reduced larval densities of both species by >98% within 72 h. Efficacy lasted one week in sun-exposed habitats but remained >50% for two weeks in shaded habitats. An. funestus spent up to two weeks before pupating (13.2(10.4-16.0) days in semi-natural; 10.0(6.6-13.5) in natural habitats), while An. arabiensis required slightly over one week (8.2 (5.8-10.6) days in semi-natural; 8.3 (5.0-11.6) in natural habitats). The findings suggest that weekly larviciding, which is essential for An. arabiensis might be more effective for An. funestus whose prolonged aquatic growth allows for repeated exposures. Additionally, the longer residual effect of biolarvicides in shaded habitats indicates they may require less frequent treatments compared to sun-exposed areas.
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Affiliation(s)
- Betwel J Msugupakulya
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Swedi K Ngajuma
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Athuman N Ngayambwa
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Baraka E Kidwanga
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Ibrahim R Mpasuka
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Prashanth Selvaraj
- Institute for Disease Modeling, Bill and Melinda Gates Foundation, Seattle, USA
- School of Life Science and Bioengineering, The Nelson Mandela African Institution of Sciences & Technology, Arusha, Tanzania
| | - Anne L Wilson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
- School of Life Science and Bioengineering, The Nelson Mandela African Institution of Sciences & Technology, Arusha, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Park Town, Republic of South Africa
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, UK
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Chan K, Konan KAC, Doudou DT, Kouadio GB, Lines J, Aunger R, N'Guessan R, Tusting LS. Rice farmers' knowledge, attitudes and practices towards mosquitoes in irrigation schemes in Côte d'Ivoire: a qualitative study. Malar J 2023; 22:352. [PMID: 37974248 PMCID: PMC10655379 DOI: 10.1186/s12936-023-04785-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Irrigated rice cultivation in sub-Saharan Africa not only brings more malaria vectors to nearby communities, but also greater malaria risk. To aid the implementation of mosquito control in rice-growing communities, it is necessary to understand how farmers understand, view and manage their responsibility in mosquito generation and whether they are interested in coordinating to minimize it. METHODS Qualitative methods (observation grids, semi-structured in-depth interviews and focus group discussions) were used to reveal the perceptions of mosquitoes and their control in two irrigated rice farming communities in central Côte d'Ivoire near the M'bé and Lokapli irrigation schemes. RESULTS All rice farmers viewed mosquitoes as severe nuisances, and most acknowledged that they caused djèkouadjo (malaria) and were less numerous during harmattan (dry season). Many study participants believed that mosquitoes originated from grasses and stagnant water around villages. Only those living closer in proximity (~ 1 km) to the paddies believed that mosquitoes came from the bas-fonds (irrigated lowlands). However, they did not associate mosquito production with rice cultivation. Some farmers believed that there were more mosquitoes in recent years than historically because of the dam construction, but remarked on the importance of the dam (and bas-fonds) for their livelihood. Many farmers were not convinced that mosquito control could occur at farm-level. CONCLUSIONS To enhance accountability amongst rice farmers, there is a need for greater awareness on the rice-mosquito link, and emphasis that the link does not imply a trade-off between food production and health. Training should not only be directed towards farming communities, but also agricultural and health extension workers. Future riceland mosquito control methods must focus on improving crop productivity and address collective action problems that may occur.
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Affiliation(s)
- Kallista Chan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK.
| | - Kouadio Aimé-Charles Konan
- Centre de Recherche Pour le Développement (CRD)/Laboratoire de Santé, Société et Développement, Université Alassane Ouattara, BP 01 V 18, Bouaké, Côte d'Ivoire
| | - Dimi Théodore Doudou
- Centre de Recherche Pour le Développement (CRD)/Laboratoire de Santé, Société et Développement, Université Alassane Ouattara, BP 01 V 18, Bouaké, Côte d'Ivoire
| | - Ghislain Brou Kouadio
- Centre de Recherche Pour le Développement (CRD)/Laboratoire de Santé, Société et Développement, Université Alassane Ouattara, BP 01 V 18, Bouaké, Côte d'Ivoire
| | - Jo Lines
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | - Robert Aunger
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | - Raphael N'Guessan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
- Institut Pierre Richet, Bouaké, Côte d'Ivoire
| | - Lucy S Tusting
- Department of Disease Control, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
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Katusi GC, Hermy MRG, Makayula SM, Ignell R, Mnyone LL, Hill SR, Govella NJ. Effect of non-human hosts on the human biting rate of primary and secondary malaria vectors in Tanzania. Malar J 2023; 22:340. [PMID: 37940967 PMCID: PMC10631174 DOI: 10.1186/s12936-023-04778-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 11/01/2023] [Indexed: 11/10/2023] Open
Abstract
BACKGROUND Malaria vectors vary in feeding preference depending on their innate behaviour, host availability and abundance. Host preference and human biting rate in malaria vectors are key factors in establishing zooprophylaxis and zoopotentiation. This study aimed at assessing the impact of non-human hosts in close proximity to humans on the human biting rate of primary and secondary malaria vectors, with varying host preferences. METHODS The effect of the presence of non-human hosts in close proximity to the human host on the mean catches per person per night, as a proxy for mosquito biting rate, was measured using mosquito-electrocuting traps (METs), in Sagamaganga, Kilombero Valley, Tanzania. Two experiments were designed: (1) a human versus a calf, each enclosed in a MET, and (2) a human surrounded by three calves versus a human alone, with each human volunteer enclosed individually in a MET spaced 10 m apart. Each experiment was conducted on alternate days and lasted for 36 nights per experiment. During each experiment, the positions of hosts were exchanged daily (except the human in experiment 2). All anopheline mosquitoes caught were assayed for Plasmodium sporozoites using enzyme-linked immunosorbent assay. RESULTS A total of 20,574 mosquitoes were captured and identified during the study, of which 3608 were anophelines (84.4% primary and 15.6% secondary malaria vectors) and 17,146 were culicines. In experiment 1, the primary malaria vector, Anopheles arabiensis, along with Culex spp. demonstrated a preference for cattle, while the primary vectors, Anopheles funestus, preferred humans. In experiment 2, both primary vectors, An. arabiensis and An. funestus, as well as the secondary vector Anopheles rivolurum, demonstrated behaviours amenable to zooprophylaxis, whereas Culex spp. increased their attraction to humans in the presence of nearby cattle. All anopheline mosquitoes tested negative for sporozoites. CONCLUSIONS The findings of this study provide support for the zooprophylaxis model for malaria vectors present in the Kilombero Valley, and for the zoopotentiation model, as it pertains to the Culex spp. in the region. However, the factors regulating zooprophylaxis and zoopotentiation are complex, with different species-dependent mechanisms regulating these behaviours, that need to be considered when designing integrated vector management programmes.
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Affiliation(s)
- Godfrey C Katusi
- Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, Morogoro, Tanzania
- Department of Microbiology, Parasitology and Biotechnology, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, P.O. Box 3019, Morogoro, Tanzania
| | - Marie R G Hermy
- Disease Vector Group, Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, P.O. Box 190, 234 22, Lomma, Sweden
| | - Samwely M Makayula
- Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, Morogoro, Tanzania
| | - Rickard Ignell
- Disease Vector Group, Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, P.O. Box 190, 234 22, Lomma, Sweden
| | - Ladslaus L Mnyone
- Institute of Pest Management, Sokoine University of Agriculture, P.O. Box 3110, Morogoro, Tanzania
| | - Sharon R Hill
- Disease Vector Group, Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, P.O. Box 190, 234 22, Lomma, Sweden.
| | - Nicodem J Govella
- Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, Off Mlabani Passage, P.O. Box 53, Ifakara, Morogoro, Tanzania
- School of Life Sciences and Bioengineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
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Msugupakulya BJ, Urio NH, Jumanne M, Ngowo HS, Selvaraj P, Okumu FO, Wilson AL. Changes in contributions of different Anopheles vector species to malaria transmission in east and southern Africa from 2000 to 2022. Parasit Vectors 2023; 16:408. [PMID: 37936155 PMCID: PMC10631025 DOI: 10.1186/s13071-023-06019-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/18/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND Malaria transmission in Africa is facilitated by multiple species of Anopheles mosquitoes. These vectors have different behaviors and vectorial capacities and are affected differently by vector control interventions, such as insecticide-treated nets and indoor residual spraying. This review aimed to assess changes in the contribution of different vector species to malaria transmission in east and southern Africa over 20 years of widespread insecticide-based vector control. METHODS We searched PubMed, Global Health, and Web of Science online databases for articles published between January 2000 and April 2023 that provided species-specific sporozoite rates for different malaria vectors in east and southern Africa. We extracted data on study characteristics, biting rates, sporozoite infection proportions, and entomological inoculation rates (EIR). Using EIR data, the proportional contribution of each species to malaria transmission was estimated. RESULTS Studies conducted between 2000 and 2010 identified the Anopheles gambiae complex as the primary malaria vector, while studies conducted from 2011 to 2021 indicated the dominance of Anopheles funestus. From 2000 to 2010, in 57% of sites, An. gambiae demonstrated higher parasite infection prevalence than other Anopheles species. Anopheles gambiae also accounted for over 50% of EIR in 76% of the study sites. Conversely, from 2011 to 2021, An. funestus dominated with higher infection rates than other Anopheles in 58% of sites and a majority EIR contribution in 63% of sites. This trend coincided with a decline in overall EIR and the proportion of sporozoite-infected An. gambiae. The main vectors in the An. gambiae complex in the region were Anopheles arabiensis and An. gambiae sensu stricto (s.s.), while the important member of the An. funestus group was An. funestus s.s. CONCLUSION The contribution of different vector species in malaria transmission has changed over the past 20 years. As the role of An. gambiae has declined, An. funestus now appears to be dominant in most settings in east and southern Africa. Other secondary vector species may play minor roles in specific localities. To improve malaria control in the region, vector control should be optimized to match these entomological trends, considering the different ecologies and behaviors of the dominant vector species.
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Affiliation(s)
- Betwel J Msugupakulya
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, PO Box 53, Ifakara, Tanzania.
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
| | - Naomi H Urio
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, PO Box 53, Ifakara, Tanzania
- School of Life Science and Bioengineering, The Nelson Mandela African Institution of Sciences & Technology, Arusha, Tanzania
| | - Mohammed Jumanne
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, PO Box 53, Ifakara, Tanzania
| | - Halfan S Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, PO Box 53, Ifakara, Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Prashanth Selvaraj
- Institute for Disease Modeling, Bill and Melinda Gates Foundation, Seattle, USA
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, PO Box 53, Ifakara, Tanzania.
- School of Life Science and Bioengineering, The Nelson Mandela African Institution of Sciences & Technology, Arusha, Tanzania.
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK.
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Park Town, Johannesburg, Republic of South Africa.
| | - Anne L Wilson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK.
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Tarimo FS, Dillip A, Kosia EM, Lwetoijera DW. Community perception of the autodissemination of pyriproxyfen for controlling malaria vectors in south-eastern Tanzania. Malar J 2023; 22:333. [PMID: 37924148 PMCID: PMC10625276 DOI: 10.1186/s12936-023-04773-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 10/26/2023] [Indexed: 11/06/2023] Open
Abstract
BACKGROUND The efficacy of the autodissemination of pyriproxyfen to control malaria vectors has been demonstrated under semi field environment in Tanzania. However, the information on how best communities should be engaged for its routine and large-scale adoption are lacking. This study assessed the community's level of knowledge, perceptions, acceptability of the autodissemination of pyriproxyfen, and the perceived risks on the safety of pyriproxyfen on the environment. METHODS This was a concurrent mixed methods study, comprised of a community-based survey of 400 household representatives and eight focus group discussions (FGDs). The study was conducted in two villages in Mlimba district in south-eastern Tanzania between June and August 2022. For the quantitative data analysis, descriptive statistics were applied using R software, while inductive approach was used for qualitative data analysis, using NVivo software. RESULTS Knowledge on autodissemination of pyriproxyfen approach was found to be relatively low among both the FGD respondents and surveyed community members (36%, n = 144). Nevertheless, when it was explained to them, the envisioned community support for the autodissemination approach was relatively high (97%, n = 388). One of the major perceived benefits of the autodissemination of pyriproxyfen was the reduction of malaria-transmitting mosquitoes and associated malaria transmission. Environmental impact of pyriproxyfen on non-target organisms and health risk to children were among the major concerns. When provided with information on the safety and its utilization particularly through autodissemination approach, 93.5% (n = 374) of the survey respondents said that they would allow the PPF-contaminated pots to be placed around their homes. Similarly, FGD respondents were receptive towards the autodissemination of pyriproxyfen, but emphasized on the need for raising awareness among community members before related field trials. CONCLUSION This study indicates a low knowledge but high support for scaling up of the autodissemination of pyriproxyfen as a complementary tool for malaria control in rural Tanzania. The Findings of this study suggest that community sensitization activities are required to improve the community's acceptability and trust of the approach before respective field trials.
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Affiliation(s)
- Felista S Tarimo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, United Republic of Tanzania.
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, P. O. Box 4447, Tengeru, Arusha, United Republic of Tanzania.
| | - Angel Dillip
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, United Republic of Tanzania
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, P. O. Box 4447, Tengeru, Arusha, United Republic of Tanzania
- Apotheker Health Access Initiative, P. O. Box 70022, Dar es Salaam, United Republic of Tanzania
| | - Efraim M Kosia
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, P. O. Box 4447, Tengeru, Arusha, United Republic of Tanzania
| | - Dickson W Lwetoijera
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, United Republic of Tanzania.
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, P. O. Box 4447, Tengeru, Arusha, United Republic of Tanzania.
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Naserrudin NA, Jiee SF, Habil B, Jantim A, Mohamed AFB, Dony JJF, Ibrahim SSA, Fornace KM, Hassan MR, Jeffree MS, Hod R, Culleton R, Ahmed K. The public health response to a Plasmodium malariae outbreak in Penampang district, Sabah during a COVID-19 movement control order. Malar J 2023; 22:292. [PMID: 37789320 PMCID: PMC10546630 DOI: 10.1186/s12936-023-04693-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 08/29/2023] [Indexed: 10/05/2023] Open
Abstract
BACKGROUND Since 2018, no indigenous human malaria cases has been reported in Malaysia. However, during the recent COVID-19 pandemic the World Health Organization is concerned that the pandemic might erode the success of malaria control as there are reports of increase malaria cases in resource limited countries. Little is known how the COVID-19 pandemic has impacted malaria in middle-income countries like Malaysia. Here the public health response to a Plasmodium malariae outbreak occurred in a village in Sabah state, Malaysia, during a COVID-19 movement control order is reported. METHODS An outbreak was declared following the detection of P. malariae in July 2020 and active case detection for malaria was performed by collecting blood samples from residents residing within 2 km radius of Moyog village. Vector prevalence and the efficacy of residual insecticides were determined. Health awareness programmes were implemented to prevent future outbreaks. A survey was conducted among villagers to understand risk behaviour and beliefs concerning malaria. RESULTS A total of 5254 blood samples collected from 19 villages. Among them, 19 P. malariae cases were identified, including the index case, which originated from a man who returned from Indonesia. His return from Indonesia and healthcare facilities visit coincided with the movement control order during COVID-19 pandemic when the healthcare facilities stretched its capacity and only serious cases were given priority. Despite the index case being a returnee from a malaria endemic area presenting with mild fever, no malaria test was performed at local healthcare facilities. All cases were symptomatic and uncomplicated except for a pregnant woman with severe malaria. There were no deaths; all patients recovered following treatment with artemether-lumefantrine combination therapy. Anopheles balabacensis and Anopheles barbirostris were detected in ponds, puddles and riverbeds. The survey revealed that fishing and hunting during night, and self-treatment for mild symptoms contributed to the outbreak. Despite the index case being a returnee from a malaria-endemic area presenting with mild fever, no malaria test was performed at local healthcare facilities. CONCLUSION The outbreak occurred during a COVID-19 movement control order, which strained healthcare facilities, prioritizing only serious cases. Healthcare workers need to be more aware of the risk of malaria from individuals who return from malaria endemic areas. To achieve malaria elimination and prevention of disease reintroduction, new strategies that include multisectoral agencies and active community participation are essential for a more sustainable malaria control programme.
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Affiliation(s)
- Nurul Athirah Naserrudin
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Malaysia
- Sabah State Health Department, Ministry of Health, Kota Kinabalu, Malaysia
| | - Sam Froze Jiee
- Department of Community Medicine and Public Health, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Kota Samarahan, Malaysia
| | - Bobby Habil
- Penampang District Health Office, Ministry of Health, Kota Kinabalu, Malaysia
| | - Anisah Jantim
- Penampang District Health Office, Ministry of Health, Kota Kinabalu, Malaysia
| | | | | | | | - Kimberly M Fornace
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, UK
- Faculty of Infectious and Tropical Diseases and Centre for Climate Change and Planetary Health, London School of Hygiene and Tropical Medicine, London, UK
- Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore, Singapore
| | - Mohd Rohaizat Hassan
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Malaysia
| | - Mohammad Saffree Jeffree
- Department of Public Health Medicine, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Malaysia
| | | | - Kamruddin Ahmed
- Borneo Medical Health and Research Centre,, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia.
- Department of Pathology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Malaysia.
- Research Center for Global and Local Infectious Diseases, Oita University, Oita, Japan.
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Kihwele F, Gavana T, Makungu C, Msuya HM, Mlacha YP, Govella NJ, Chaki PP, Sunguya BF. Exploring activities and behaviours potentially increases school-age children's vulnerability to malaria infections in south-eastern Tanzania. Malar J 2023; 22:293. [PMID: 37789435 PMCID: PMC10548596 DOI: 10.1186/s12936-023-04703-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 09/02/2023] [Indexed: 10/05/2023] Open
Abstract
BACKGROUND Strengthening malaria control activities in Tanzania has dramatically declined human malaria infections. However, there is an increasing epidemiological shift in the burden on school-age children. The underlying causes for such an epidemiological shift remain unknown in this context. This study explored activities and behaviours that could increase the vulnerability of school-age children to transmission risk to provide insight into protection gap with existing interventions and opportunities for supplementary interventions. METHODS This cross-sectional study conducted twenty-four focus group discussions (FGDs) in three districts of Rufiji, Kibiti and Kilwa in south-eastern Tanzania. Sixteen FGDs worked with school-age children (13 to 18 years) separating girls and boys and eight FGDs with their parents in mixed-gender groups. A total of 205 community members participated in FGDs across the study area. Of them, 72 participants were parents, while 133 were school-age children (65 boys and 68 girls). RESULTS Routine domestic activities such as fetching water, washing kitchen utensils, cooking, and recreational activities such as playing and watching television and studying were the reported activities that kept school-age children outdoors early evening to night hours (between 18:00 and 23:00). Likewise, the social and cultural events including initiation ceremonies and livelihood activities also kept this age group outdoors from late evening to early night and sometimes past midnight hours. Parents migrating to farms from December to June, leaving behind school-age children unsupervised affecting their net use behaviour plus spending more time outdoors at night, and the behaviour of children sprawling legs and hands while sleeping inside treated bed nets were identified as potential risks to infectious mosquito bites. CONCLUSION The risky activities, behaviours, and social events mostly occurring outdoors might increase school-age children's vulnerability to malaria infections. The findings provide preliminary insight on potential risk factors for persisting transmission. Further studies to quantify the risk behaviour and activities are recommended to establish the magnitude and anticipated impact on supplementary control strategies to control infection in school-age children.
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Affiliation(s)
- Fadhila Kihwele
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania.
- Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es Salaam, United Republic of Tanzania.
| | - Tegemeo Gavana
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
- Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es Salaam, United Republic of Tanzania
| | - Christina Makungu
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
| | - Hajirani M Msuya
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
| | - Yeromin P Mlacha
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
| | - Nicodem James Govella
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
- School of Life Sciences and Bioengineering (LISBE), Nelson Mandela African Institution of Science and Technology, P.O. BOX 447, Tengeru, Arusha, United Republic of Tanzania
| | - Prosper Pius Chaki
- Environmental Health and Ecological Sciences Department, #5 Ifakara Street, Plot 463 Mikocheni, P.O. Box 78373, Dar Es Salaam, United Republic of Tanzania
- The Pan African Mosquito Control Association (PAMCA), KEMRI Headquarters, Mbagathi Road Nairobi, Nairobi, 54840-00200, Kenya
| | - Bruno Fokas Sunguya
- Muhimbili University of Health and Allied Sciences, P.O. Box 65001, Dar es Salaam, United Republic of Tanzania
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22
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Tondossama N, Virgillito C, Coulibaly ZI, Pichler V, Dia I, della Torre A, Touré AO, Adja AM, Caputo B. A High Proportion of Malaria Vector Biting and Resting Indoors despite Extensive LLIN Coverage in Côte d'Ivoire. INSECTS 2023; 14:758. [PMID: 37754726 PMCID: PMC10532360 DOI: 10.3390/insects14090758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/30/2023] [Accepted: 09/05/2023] [Indexed: 09/28/2023]
Abstract
Malaria is still a leading cause mortality in Côte d'Ivoire despite extensive LLINs coverage. We present the results of an entomological survey conducted in a coastal and in an inland village with the aim to estimate Anopheles gambiae sensu lato (s.l.) female's abundance indoor/outdoor and Plasmodium falciparum infection rate and analyze the occurrence of blood-feeding in relation to LLINs use. Pyrethrum spray (PSC) and window exit traps (WT) collections were carried out to target endophagic/endophilic and endophagic/exophilic females, respectively. Data on LLINs use in sampled houses were collected. (1) high levels of malaria transmission despite LLINs coverage >70% (~1 An. gambiae s.l. predicted mean/person/night and ~5% Plasmodium falciparum infection rate); (2) 46% of females in the PSC sample were blood-fed, suggesting that they fed on an unprotected host inside the house; (3) 81% of females in WT were unfed, suggesting that they were leaving the house to find an available host. Model estimates that if everyone sleeps under LLINs the probability for a mosquito to bite decreases of 48% and 95% in the coastal and inland village, respectively. The results show a high proportion of mosquito biting and resting indoors despite extensive LLINs. The biological/epidemiological determinants of accounting for these results merit deeper investigations.
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Affiliation(s)
- Naminata Tondossama
- Entomology and Herpetology Unit, Institut Pasteur de Côte d’Ivoire, Abidjan 01 PB 490, Côte d’Ivoire; (N.T.); (Z.I.C.)
- Laboratoire de Biologie et Santé, UFR Biosciences, Université Félix Houphouët Boigny Cocody, Abidjan 01 BP V34, Côte d’Ivoire;
| | - Chiara Virgillito
- Department of Public Health and Infectious Diseases, Institute Pasteur Italia-Fondazione Cenci-Bolognetti, University of Rome ‘Sapienza’, Piazzale Aldo Moro 5, 00185 Rome, Italy; (C.V.)
| | - Zanakoungo Ibrahima Coulibaly
- Entomology and Herpetology Unit, Institut Pasteur de Côte d’Ivoire, Abidjan 01 PB 490, Côte d’Ivoire; (N.T.); (Z.I.C.)
| | - Verena Pichler
- Department of Public Health and Infectious Diseases, Institute Pasteur Italia-Fondazione Cenci-Bolognetti, University of Rome ‘Sapienza’, Piazzale Aldo Moro 5, 00185 Rome, Italy; (C.V.)
| | - Ibrahima Dia
- Pôle de Zoologie Médicale, Institut Pasteur de Dakar, 36 Avenue Pasteur, Dakar BP 220, Senegal;
| | - Alessandra della Torre
- Department of Public Health and Infectious Diseases, Institute Pasteur Italia-Fondazione Cenci-Bolognetti, University of Rome ‘Sapienza’, Piazzale Aldo Moro 5, 00185 Rome, Italy; (C.V.)
| | - Andre Offianan Touré
- Unité de Paludologie, Institut Pasteur de Côte d’Ivoire, Abidjan 01 PB 490, Côte d’Ivoire;
| | - Akré Maurice Adja
- Laboratoire de Biologie et Santé, UFR Biosciences, Université Félix Houphouët Boigny Cocody, Abidjan 01 BP V34, Côte d’Ivoire;
- Institut Pierre Richet, Institut National de Santé Publique, Bouaké 01 BP 1500, Côte d’Ivoire
| | - Beniamino Caputo
- Department of Public Health and Infectious Diseases, Institute Pasteur Italia-Fondazione Cenci-Bolognetti, University of Rome ‘Sapienza’, Piazzale Aldo Moro 5, 00185 Rome, Italy; (C.V.)
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Govella NJ, Johnson PCD, Killeen GF, Ferguson HM. Heritability of biting time behaviours in the major African malaria vector Anopheles arabiensis. Malar J 2023; 22:238. [PMID: 37587487 PMCID: PMC10433675 DOI: 10.1186/s12936-023-04671-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 08/07/2023] [Indexed: 08/18/2023] Open
Abstract
BACKGROUND The use of insecticide-treated nets for malaria control has been associated with shifts in mosquito vector feeding behaviour including earlier and outdoor biting on humans. The relative contribution of phenotypic plasticity and heritability to these behavioural shifts is unknown. Elucidation of the mechanisms behind these shifts is crucial for anticipating impacts on vector control. METHODS A novel portable semi-field system (PSFS) was used to experimentally measure heritability of biting time in the malaria vector Anopheles arabiensis in Tanzania. Wild An. arabiensis from hourly collections using the human landing catch (HLC) method were grouped into one of 3 categories based on their time of capture: early (18:00-21:00), mid (22:00-04:00), and late (05:00-07:00) biting, and placed in separate holding cages. Mosquitoes were then provided with a blood meal for egg production and formation of first filial generation (F1). The F1 generation of each biting time phenotype category was reared separately, and blood fed at the same time as their mothers were captured host-seeking. The resultant eggs were used to generate the F2 generation for use in heritability assays. Heritability was assessed by releasing F2 An. arabiensis into the PSFS, recording their biting time during a human landing catch and comparing it to that of their F0 grandmothers. RESULTS In PSFS assays, the biting time of F2 offspring (early: 18:00-21:00, mid: 22:00-04:00 or late: 05:00-07:00) was significantly positively associated with that of their wild-caught F0 grandmothers, corresponding to an estimated heritability of 0.110 (95% CI 0.003, 0.208). F2 from early-biting F0 were more likely to bite early than F2 from mid or late-biting F0. Similarly, the probability of biting late was higher in F2 derived from mid and late-biting F0 than from early-biting F0. CONCLUSIONS Despite modest heritability, our results suggest that some of the variation in biting time is attributable to additive genetic variation. Selection can, therefore, act efficiently on mosquito biting times, highlighting the need for control methods that target early and outdoor biting mosquitoes.
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Affiliation(s)
- Nicodem J Govella
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Dar es Salaam, Tanzania.
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.
- School of Life Sciences and Bioengineering, Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania.
| | - Paul C D Johnson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Gerry F Killeen
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Dar es Salaam, Tanzania
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
- School of Biological, Earth & Environmental Sciences and Environmental Research Institute, University College Cork, Cork, T23 N73K, Republic of Ireland
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
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Conn JE, Bickersmith SA, Saavedra MP, Morales JA, Alava F, Diaz Rodriguez GA, del Aguila Morante CR, Tong CG, Alvarez-Antonio C, Daza Huanahui JM, Vinetz JM, Gamboa D. Natural Infection of Nyssorhynchus darlingi and Nyssorhynchus benarrochi B with Plasmodium during the Dry Season in the Understudied Low-Transmission Setting of Datem del Marañon Province, Amazonian Peru. Am J Trop Med Hyg 2023; 109:288-295. [PMID: 37364858 PMCID: PMC10397451 DOI: 10.4269/ajtmh.23-0058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/25/2023] [Indexed: 06/28/2023] Open
Abstract
The persistence of malaria hotspots in Datem del Marañon Province, Peru, prompted vector control units at the Ministry of Health, Loreto Department, to collaborate with the Amazonian International Center of Excellence for Malaria Research to identify the main vectors in several riverine villages that had annual parasite indices > 15 in 2018-2019. Anophelinae were collected indoors and outdoors for two 12-hour nights/community during the dry season in 2019 using human landing catch. We identified four species: Nyssorhynchus benarrochi B, Nyssorhynchus darlingi, Nyssorhynchus triannulatus, and Anopheles mattogrossensis. The most abundant, Ny. benarrochi B, accounted for 96.3% of the total (7,550/7,844), of which 61.5% were captured outdoors (4,641/7,550). Six mosquitoes, one Ny. benarrochi B and five Ny. darlingi, were infected by Plasmodium falciparum or Plasmodium vivax. Human biting rates ranged from 0.5 to 592.8 bites per person per hour for Ny. benarrochi B and from 0.5 to 32.0 for Ny. darlingi, with entomological inoculation rates as high as 0.50 infective bites per night for Ny. darlingi and 0.25 for Ny. benarrochi B. These data demonstrate the risk of malaria transmission by both species even during the dry season in villages in multiple watersheds in Datem del Marañon province.
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Affiliation(s)
- Jan E. Conn
- Wadsworth Center, New York State Department of Health, Albany, New York
- Department of Biomedical Sciences, School of Public Health, State University of New York-Albany, Albany, New York
| | | | - Marlon P. Saavedra
- Amazonian International Center of Excellence for Malaria Research, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Juliana A. Morales
- Amazonian International Center of Excellence for Malaria Research, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | | | | | - Carlos G. Tong
- Laboratorio de Salud Pública-Gerencia Regional de Salud de Loreto, GERESA, Iquitos, Peru
| | | | - Jesus M. Daza Huanahui
- Red de Salud Datem del Marañon – Gerencia Regional de Salud de Loreto, GERESA, Iquitos, Peru
| | - Joseph M. Vinetz
- Amazonian International Center of Excellence for Malaria Research, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Laboratorio de Malaria: Parásitos y Vectores, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut
- VA Connecticut Healthcare System, West Haven, Connecticut
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Dionicia Gamboa
- Amazonian International Center of Excellence for Malaria Research, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Laboratorio de Malaria: Parásitos y Vectores, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
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Muyaga LL, Meza FC, Kahamba NF, Njalambaha RM, Msugupakulya BJ, Kaindoa EW, Ngowo HS, Okumu FO. Effects of vegetation densities on the performance of attractive targeted sugar baits (ATSBs) for malaria vector control: a semi-field study. Malar J 2023; 22:190. [PMID: 37344867 DOI: 10.1186/s12936-023-04625-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 06/16/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND Attractive targeted sugar baits (ATSBs) control sugar-feeding mosquitoes with oral toxicants, and may effectively complement core malaria interventions, such as insecticide-treated nets even where pyrethroid-resistance is widespread. The technology is particularly efficacious in arid and semi-arid areas. However, their performance remains poorly-understood in tropical areas with year-round malaria transmission, and where the abundant vegetation constitutes competitive sugar sources for mosquitoes. This study compared the efficacies of ATSBs (active ingredient: 2% boric acid) in controlled settings with different vegetation densities. METHODS Potted mosquito-friendly plants were introduced inside semi-field chambers (9.6 m by 9.6 m) to simulate densely-vegetated, sparsely-vegetated, and bare sites without any vegetation (two chambers/category). All chambers had volunteer-occupied huts. Laboratory-reared Anopheles arabiensis were released nightly (200/chamber) and host-seeking females recaptured using human landing catches outdoors (8.00 p.m.-9.00 p.m.) and CDC-light traps indoors (9.00 p.m.-6.00 a.m.). Additionally, resting mosquitoes were collected indoors and outdoors each morning using Prokopack aspirators. The experiments included a "before-and-after" set-up (with pre-ATSBs, ATSBs and post-ATSBs phases per chamber), and a "treatment vs. control" set-up (where similar chambers had ATSBs or no ATSBs). The experiments lasted 84 trap-nights. RESULTS In the initial tests when all chambers had no vegetation, the ATSBs reduced outdoor-biting by 69.7%, indoor-biting by 79.8% and resting mosquitoes by 92.8%. In tests evaluating impact of vegetation, the efficacy of ATSBs against host-seeking mosquitoes was high in bare chambers (outdoors: 64.1% reduction; indoors: 46.8%) but modest or low in sparsely-vegetated (outdoors: 34.5%; indoors: 26.2%) and densely-vegetated chambers (outdoors: 25.4%; indoors: 16.1%). Against resting mosquitoes, the ATSBs performed modestly across settings (non-vegetated chambers: 37.5% outdoors and 38.7% indoors; sparsely-vegetated: 42.9% outdoors and 37.5% indoors; densely-vegetated: 45.5% outdoors and 37.5% indoors). Vegetation significantly reduced the ATSBs efficacies against outdoor-biting and indoor-biting mosquitoes but not resting mosquitoes. CONCLUSION While vegetation can influence the performance of ATSBs, the devices remain modestly efficacious in both sparsely-vegetated and densely-vegetated settings. Higher efficacies may occur in places with minimal or completely no vegetation, but such environments are naturally unlikely to sustain Anopheles populations or malaria transmission in the first place. Field studies therefore remain necessary to validate the efficacies of ATSBs in the tropics.
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Affiliation(s)
- Letus L Muyaga
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania.
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK.
| | - Felician C Meza
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Najat F Kahamba
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Rukiyah M Njalambaha
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
| | - Betwel J Msugupakulya
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Emmanuel W Kaindoa
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Life Sciences and Biotechnology, Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania
- Faculty of Health Sciences, School of Pathology, Centre for Emerging Zoonotic and Parasitic Diseases, Wits Research Institute for Malaria, University of the Witwatersrand, National Institute for Communicable Diseases, Johannesburg, South Africa
| | - Halfan S Ngowo
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Fredros O Okumu
- Department of Environmental Health, and Ecological Science, Ifakara Health Institute, Morogoro, United Republic of Tanzania.
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK.
- School of Life Sciences and Biotechnology, Nelson Mandela African Institution of Science and Technology, Arusha, United Republic of Tanzania.
- School of Public Health, University of the Witwatersrand, Johannesburg, South Africa.
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26
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Talebzadeh F, Raoofian R, Ghadipasha M, Moosa-Kazemi SH, Akbarzadeh K, Oshaghi MA. Sex-typing of ingested human blood meal in Anopheles stephensi mosquito based on the amelogenin gene. Exp Parasitol 2023; 248:108517. [PMID: 36967035 DOI: 10.1016/j.exppara.2023.108517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/23/2023] [Accepted: 03/24/2023] [Indexed: 03/28/2023]
Abstract
Identifying the sex of human hosts of insect disease vectors, using PCR amplification of the amelogenin gene (AMEL) from the ingested blood meal is an increasingly useful technique for epidemiological studies of vector-borne diseases, as well as within the criminal justice system. Detection of DNA from ingested blood is influenced by the choice of DNA extraction method, genomic target region, type and length of PCR, and rate of degradation in the DNA samples over time. Here, we have tested two types of PCR (i.e. conventional and nested), producing differently-sized PCR products, in time-course assays targeting the human AMEL gene in Anopheles stephensi mosquitoes that were fed on human male and female blood. The fed female mosquitoes were allowed to digest at 28 °C for times ranging from 0 to 120 h. Three AMEL primer pairs were used to amplify three sequences that were 977, 539, and 106 bp for the X chromosome and 790, 355, and 112 bp for Y. We found that time since feeding had a significant negative effect on the success of PCR amplification. The shortest fragments (106 and 112 bp) were amplified for the longest time after blood feeding (up to 60 h), whereas the medium and longest loci were not amplified by conventional PCR even at 0 h. However, the nested PCR protocol, targeting the medium sequence, could detect small amounts of human DNA up to 36 h (1.5 days) after the blood meal. The shortest PCR assay standardized herein successfully detected small amounts of human DNA in female mosquitoes up to 60 h after the blood meal. This assay represents a promising tool for identifying the sex of the human host from the blood meal in field-collected female mosquitoes.
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Affiliation(s)
- Fahimeh Talebzadeh
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | - Seyed Hassan Moosa-Kazemi
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Kamran Akbarzadeh
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ali Oshaghi
- Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
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Namountougou M, Kientega M, Kaboré PDA, Soma DD, Pare Toe L, Sawadogo JME, Birba WJ, Gnankiné O, Dabiré KR, Okumu F, Diabaté A. Residual Malaria Transmission: magnitude and drivers of persistent Plasmodium infections despite high coverage of control interventions in Burkina Faso, West Africa. Acta Trop 2023; 242:106913. [PMID: 36997012 DOI: 10.1016/j.actatropica.2023.106913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/04/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023]
Abstract
This study collected baseline data on malaria vectors to characterize the drivers and the factors of persistent malaria transmission in two villages in the western part of Burkina Faso. Mosquitoes were collected in each village using the Human landing catch and pyrethrum spray catch and identified using the morphological keys. Molecular analyses were performed for the identification of An. gambiae complex species, the detection of Plasmodium infection and kdr-995F mutation. Anopheles mosquito larvae were also collected in the same villages, reared to adult's stage for the WHO tube and cone tests performing. The physical integrity of the LLINs already used by people in each village was assessed using the proportional hole index (pHI). An. gambiae s.l. was the main malaria vector accounting for 79.82% (5560/6965) of all collected mosquitoes. The biting pattern of An. gambiae s.l. was almost constant during the survey with an early aggressiveness before 8 p.m. and later biting activity after 6 a.m. The EIR varied from 0.13 to 2.55 infected bites per human per night (average: 1.03 infected bites per human per night). An. gambiae s.l. populations were full susceptible to Chlorpyrifos-methyl (0.4%) and Malathion (5%) with high kdr-995F mutation frequencies (>0.8). The physical integrity assessment showed high proportion of good nets in Santidougou compared to those collected in Kimidougou. This study highlighted a persistence of malaria transmission despite the intense use of vector control tools as LLINs and IRS by correlating mosquito biting time and human behavior. It provided a baseline guide for the monitoring of the residual malaria transmission in sub-Saharan Africa and encouraging the development of new alternative strategies to support the current malaria control tools.
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Bofu RM, Santos EM, Msugupakulya BJ, Kahamba NF, Swilla JD, Njalambaha R, Kelly AH, Lezaun J, Christofides N, Okumu FO, Finda MF. The needs and opportunities for housing improvement for malaria control in southern Tanzania. Malar J 2023; 22:69. [PMID: 36849883 PMCID: PMC9972788 DOI: 10.1186/s12936-023-04499-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 02/16/2023] [Indexed: 03/01/2023] Open
Abstract
BACKGROUND Malaria disproportionately affects low-income households in rural communities where poor housing is common. Despite evidence that well-constructed and mosquito-proofed houses can reduce malaria risk, housing improvement is rarely included in malaria control toolboxes. This study assessed the need, magnitude, and opportunities for housing improvement to control malaria in rural Tanzania. METHODS A mixed-methods study was conducted in 19 villages across four district councils in southern Tanzania. A structured survey was administered to 1292 community members to assess need, perceptions, and opportunities for housing improvement for malaria control. Direct observations of 802 houses and surrounding environments were done to identify the actual needs and opportunities, and to validate the survey findings. A market survey was done to assess availability and cost of resources and services necessary for mosquito-proofing homes. Focus group discussions were conducted with key stakeholders to explore insights on the potential and challenges of housing improvement as a malaria intervention. RESULTS Compared to other methods for malaria control, housing improvement was among the best understood and most preferred by community members. Of the 735 survey respondents who needed housing improvements, a majority needed window screening (91.1%), repairs of holes in walls (79.4%), door covers (41.6%), closing of eave spaces (31.2%) and better roofs (19.0%). Community members invested significant efforts to improve their own homes against malaria and other dangers, but these efforts were often slow and delayed due to high costs and limited household incomes. Study participants suggested several mechanisms of support to improve their homes, including government loans and subsidies. CONCLUSION Addressing the need for housing improvement is a critical component of malaria control efforts in southern Tanzania. In this study, a majority of the community members surveyed needed modest modifications and had plans to work on those modifications. Without additional support, their efforts were however generally slow; households would take years to sufficiently mosquito-proof their houses. It is, therefore, crucial to bring together the key players across sectors to reduce barriers in malaria-proofing housing in endemic settings. These may include government subsidies or partnerships with businesses to make housing improvement more accessible and affordable to residents.
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Affiliation(s)
- Ramadhani M Bofu
- Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania.
- School of Life Sciences and Bioengineering, The Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha, Tanzania.
- Mpwapwa Institute of Health and Allied Sciences, The Ministry of Health, P.O. Box 743, Dodoma, Tanzania.
| | - Ellen M Santos
- Department of Applied Health, Southern Illinois University Edwardsville, Edwardsville, USA
| | - Betwel J Msugupakulya
- Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Najat F Kahamba
- Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G128QQ, UK
| | - Joseph D Swilla
- School of Life Sciences and Bioengineering, The Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha, Tanzania
- Department of Molecular Biology and Biotechnology, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Rukiyah Njalambaha
- Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
| | - Ann H Kelly
- Department of Global Health and Social Medicine, King's College London, London, UK
| | - Javier Lezaun
- Institute for Science, Innovation, and Society, School of Anthropology and Museum Ethnography, University of Oxford, Oxford, UK
| | - Nicola Christofides
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 1 Smuts Avenue, Braamfontein, Johannesburg, 2000, South Africa
| | - Fredros O Okumu
- Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Life Sciences and Bioengineering, The Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha, Tanzania
- School of Biodiversity, One Health and Veterinary Medicine, University of Glasgow, Glasgow, G128QQ, UK
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 1 Smuts Avenue, Braamfontein, Johannesburg, 2000, South Africa
| | - Marceline F Finda
- Department of Environmental Health and Ecological Sciences, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Life Sciences and Bioengineering, The Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha, Tanzania
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Salomé G, Riddin M, Braack L. Species Composition, Seasonal Abundance, and Biting Behavior of Malaria Vectors in Rural Conhane Village, Southern Mozambique. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3597. [PMID: 36834293 PMCID: PMC9966379 DOI: 10.3390/ijerph20043597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
Malaria vector surveillance provides important data to inform the effective planning of vector control interventions at a local level. The aim of this study was to determine the species diversity and abundance, biting activity, and Plasmodium infectivity of Anopheles mosquitoes from a rural village in southern Mozambique. Human landing catches were performed monthly between December 2020 and August 2021. All collected Anopheles were identified to the species level and tested for the presence of malaria parasites. Eight Anopheles species were identified among the 1802 collected anophelines. Anopheles gambiae sensu lato (s.l.) were the most abundant (51.9%) and were represented by Anopheles quadriannulatus and Anopheles arabiensis. Anopheles funestus s.l. represented 4.5%. The biting activity of An. arabiensis was more pronounced early in the evening and outdoors, whereas that of An. funestus sensu stricto (s.s.) was more intense late in the night, with no significant differences in location. One An. funestus s.s. and one An. arabiensis, both collected outdoors, were infected with Plasmodium falciparum. The overall entomologic inoculation rate was estimated at 0.015 infective bites per person per night. The significant outdoor and early evening biting activity of An. arabiensis and An. funestus found in this village may negatively impact the effectiveness of current vector control interventions. Additional vector control tools that can target these mosquitoes are needed.
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Affiliation(s)
- Graça Salomé
- UP Institute for Sustainable Malaria Control, School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria, Pretoria 0028, South Africa
- Department of Physiological Sciences, Faculty of Medicine, Eduardo Mondlane University, 702 Salvador Allende Ave., Maputo P.O. Box 257, Mozambique
| | - Megan Riddin
- UP Institute for Sustainable Malaria Control, School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria, Pretoria 0028, South Africa
| | - Leo Braack
- UP Institute for Sustainable Malaria Control, School of Health Systems and Public Health, Faculty of Health Sciences, University of Pretoria, Pretoria 0028, South Africa
- Malaria Consortium, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajavithi Rd, Ratchathewi, Bangkok 10400, Thailand
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Mmbando AS, Mponzi WP, Ngowo HS, Kifungo K, Kasubiri R, Njalambaha RM, Gavana T, Eiras AE, Batista EPA, Finda MF, Sangoro OP, Okumu FO. Small-scale field evaluation of transfluthrin-treated eave ribbons and sandals for the control of malaria vectors in rural Tanzania. Malar J 2023; 22:43. [PMID: 36739391 PMCID: PMC9898903 DOI: 10.1186/s12936-023-04476-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 02/01/2023] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Early-evening and outdoor-biting mosquitoes may compromise the effectiveness of frontline malaria interventions, notably insecticide-treated nets (ITNs). This study aimed to evaluate the efficacy of low-cost insecticide-treated eave ribbons and sandals as supplementary interventions against indoor-biting and outdoor-biting mosquitoes in south-eastern Tanzania, where ITNs are already widely used. METHODS This study was conducted in three villages, with 72 households participating (24 households per village). The households were divided into four study arms and assigned: transfluthrin-treated sandals (TS), transfluthrin-treated eave ribbons (TER), a combination of TER and TS, or experimental controls. Each arm had 18 households, and all households received new ITNs. Mosquitoes were collected using double net traps (to assess outdoor biting), CDC light traps (to assess indoor biting), and Prokopack aspirators (to assess indoor resting). Protection provided by the interventions was evaluated by comparing mosquito densities between the treatment and control arms. Additional tests were done in experimental huts to assess the mortality of wild mosquitoes exposed to the treatments or controls. RESULTS TERs reduced indoor-biting, indoor-resting and outdoor-biting Anopheles arabiensis by 60%, 73% and 41%, respectively, while TS reduced the densities by 18%, 40% and 42%, respectively. When used together, TER & TS reduced indoor-biting, indoor-resting and outdoor-biting An. arabiensis by 53%, 67% and 57%, respectively. Protection against Anopheles funestus ranged from 42 to 69% with TER and from 57 to 74% with TER & TS combined. Mortality of field-collected mosquitoes exposed to TER, TS or both interventions was 56-78% for An. arabiensis and 47-74% for An. funestus. CONCLUSION Transfluthrin-treated eave ribbons and sandals or their combination can offer significant household-level protection against malaria vectors. Their efficacy is magnified by the transfluthrin-induced mortality, which was observed despite the prevailing pyrethroid resistance in the study area. These results suggest that TER and TS could be useful supplementary tools against residual malaria transmission in areas where ITN coverage is high but additional protection is needed against early-evening and outdoor-biting mosquitoes. Further research is needed to validate the performance of these tools in different settings, and assess their long-term effectiveness and feasibility for malaria control.
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Affiliation(s)
- Arnold S Mmbando
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania.
| | - Winifrida P Mponzi
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
| | - Halfan S Ngowo
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Khamis Kifungo
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
| | - Robert Kasubiri
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
| | - Rukiyah M Njalambaha
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
| | - Tegemeo Gavana
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
| | - Alvaro E Eiras
- Laboratory of Technological Innovation of Vector Control, Department of Parasitology, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Elis P A Batista
- Laboratory of Technological Innovation of Vector Control, Department of Parasitology, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Marceline F Finda
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Republic of South Africa
| | - Onyango P Sangoro
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
- Human Health Theme, International Centre of Insect Physiology and Ecology (ICIPE), Nairobi City, Kenya
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania.
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, Republic of South Africa.
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.
- School of Life Science and Bioengineering, Nelson Mandela African Institution of Science & Technology, Arusha, Tanzania.
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Agyemang-Badu SY, Awuah E, Oduro-Kwarteng S, Dzamesi JYW, Dom NC, Kanno GG. Environmental Management and Sanitation as a Malaria Vector Control Strategy: A Qualitative Cross-Sectional Study Among Stakeholders, Sunyani Municipality, Ghana. ENVIRONMENTAL HEALTH INSIGHTS 2023; 17:11786302221146890. [PMID: 36620305 PMCID: PMC9817013 DOI: 10.1177/11786302221146890] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 12/05/2022] [Indexed: 06/06/2023]
Abstract
BACKGROUND For centuries malaria infection remains a public health burden globally as well as in the Sunyani Municipality. This exploratory qualitative study aimed to assess the prospects of environmental management and sanitation (EMS) as a malaria vector control strategy among key stakeholders involved in the prevention and control of malaria in Sunyani Municipality, Ghana. METHOD We used an exploratory qualitative study and a designed focus group discussion (FGD) guide (with specific research questions) to solicit opinions and/or views among Malaria Control Focal Persons, Environmental Health Officers (Health Inspectors), and Honourable Assembly Members. Data were collected between December 2019 and February 2020. The responses were analyzed according to the specific research questions. RESULT Findings from this study shows that high government support and/or political will by investing in environmental sanitation infrastructure, creating the enabling environment for strict enforcement of environmental sanitation bye-laws by Environmental Health Officers/Health Inspectors, effective and efficient collaboration among key stakeholders and organization of communal labor activities is likely to help reduce the majority of the mosquito breeding sites. CONCLUSION The prospects of environmental management and sanitation (EMS) as a vector control strategy, look promisingly very high, pertinent, and workable and a likelihood game changer of winning the fight against malaria due to the residual transmission that is happening outdoors. However, EMS can be employed as a supplementary method to the current core vector control methods if the following conditions and bottlenecks are addressed and in place: (a) Effective collaboration among key stakeholders at all levels; (b) Adequate allocation of funds to the Environmental Health and Sanitation Department; (c) Enactment of robust educational campaigns across all educational levels and via different media; (d) Recognition, empowerment, and adequate resourcing of Environmental Health Officers; (e) Adherence to the building regulations to prevent encroachment of natural wetlands; (f) Revision of fees/fines and prosecution of sanitary offenders; (g) Enactment of an Environmental Sanitation Day (ESD), and establishment of the Environmental Health and Sanitation Fund (EHSF).
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Affiliation(s)
- Samuel Yaw Agyemang-Badu
- Regional Water and Environmental
Sanitation Centre-Kumasi (RWESCK), World Bank African Centre of Excellence (ACE).
Department of Civil Engineering, Kwame Nkrumah University of Science and Technology
(KNUST), Kumasi, Ashanti Region, Ghana
- College of Health-Yamfo, Department of
Community Health, Ministry of Health, Health Training Institution (MOH-HTI),
Sunyani-Yamfo, Ghana
| | - Esi Awuah
- Regional Water and Environmental
Sanitation Centre-Kumasi (RWESCK), World Bank African Centre of Excellence (ACE).
Department of Civil Engineering, Kwame Nkrumah University of Science and Technology
(KNUST), Kumasi, Ashanti Region, Ghana
| | - Sampson Oduro-Kwarteng
- Regional Water and Environmental
Sanitation Centre-Kumasi (RWESCK), World Bank African Centre of Excellence (ACE).
Department of Civil Engineering, Kwame Nkrumah University of Science and Technology
(KNUST), Kumasi, Ashanti Region, Ghana
| | - Justice Yao Woelinam Dzamesi
- College of Health-Yamfo, Department of
Physician Assistantship, Ministry of Health, Health Training Institution (MOH-HTI),
Sunyani-Yamfo, Ghana
| | - Nazri Che Dom
- Centre of Environmental Health and
Safety, Faculty of Health Sciences, Universiti Teknologi MARA, Selangor,
Malaysia
| | - Girum Gebremeskel Kanno
- Department of Environmental Health,
College of Health and Medical Sciences, Dilla University, Addis Ababa,
Ethiopia
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Bamou R, Tchuinkam T, Kopya E, Awono-Ambene P, Njiokou F, Mwangangi J, Antonio-Nkondjio C. Knowledge, attitudes, and practices regarding malaria control among communities living in the south Cameroon forest region. IJID REGIONS 2022; 5:169-176. [PMID: 36467507 PMCID: PMC9713328 DOI: 10.1016/j.ijregi.2022.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 11/02/2022] [Accepted: 11/04/2022] [Indexed: 05/28/2023]
Abstract
OBJECTIVE This study assessed knowledge, attitudes, and practices (KAP) regarding malaria among communities living in the equatorial forest region of south Cameroon. METHODS The study was conducted in Olama and Nyabessan. Interviews were undertaken using a semi-structured questionnaire for data collection on KAP, while malaria rapid diagnostic testing, using SD BIOLINE kits, was employed for malaria parasite detection. RESULTS In total, 186 heads of households (HoH), comprising 105 (56.45%) males and 81 (43.45%) females, were interviewed. The majority of HoH demonstrated good knowledge of malaria (86.56%; n = 161) and control measures, with a high proportion of long-lasting insecticidal net (LLIN) ownership (96.8%; n = 180). More than two-thirds (81.1%; n = 151) of households owned at least one LLIN for two people. The majority of HoH (85.40%) declared visiting hospitals or clinics in cases of suspected malaria. Malaria parasite prevalence was high in the two study sites (63.9% in Nyabessan and 48.65% in Olama), and varied according to age, house type, and sleeping time. CONCLUSION The study indicated that despite good knowledge of malaria, high possession and utilization of control measures by population, transmission of malaria still persist in the area. The study stress the need for implementing additional control measures to improve the fight against malaria in the area.
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Key Words
- Cameroon
- HoH, head of household
- IRS, indoor residual spraying
- KAP
- KAP, knowledge, attitude, and practice
- LLIN, long-lasting insecticidal net
- MoH, Ministry of Health. PBO, piperonyl butoxide
- NMCP, National Malaria Control Program
- WHO, World Health Organization
- forested area
- mRDT, malaria rapid diagnostic test
- malaria determinants
- malaria prevalence
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Affiliation(s)
- Roland Bamou
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science of the University of Dschang
- Organisation de Coordination pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaounde, Cameroon
| | - Timoléon Tchuinkam
- Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Science of the University of Dschang
| | - Edmond Kopya
- Organisation de Coordination pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaounde, Cameroon
- Laboratory of Parasitology and Ecology, Faculty of Sciences, University of Yaoundé, Yaoundé, Cameroon
| | - Parfait Awono-Ambene
- Organisation de Coordination pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaounde, Cameroon
| | - Flobert Njiokou
- Laboratory of Parasitology and Ecology, Faculty of Sciences, University of Yaoundé, Yaoundé, Cameroon
| | - Joseph Mwangangi
- Center for Geographic Medicine Research, Kenya Medical Research Institute (KEMRI), Kilifi, Kenya
- Centre for Vector Disease Control, Kenya Medical Research Institute (KEMRI), Kwale, Kenya
| | - Christophe Antonio-Nkondjio
- Organisation de Coordination pour la Lutte Contre les Endémies en Afrique Centrale (OCEAC), Yaounde, Cameroon
- Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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Githu V, Baravuga ME, Mbarawa A, Msuya HM, Mlacha YP, Chaki PP, Kiware S, Mirzai N, Ferguson HM, Govella NJ. Comparative evaluation of different versions of exposure-free mosquito electrocuting traps and barrier screen trap for monitoring outdoor densities and biting time phenotypes by malaria and filariasis vectors in Tanzania. Parasit Vectors 2022; 15:420. [PMID: 36369172 PMCID: PMC9652990 DOI: 10.1186/s13071-022-05549-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 10/08/2022] [Indexed: 11/13/2022] Open
Abstract
Background Estimating human exposure to mosquito vectors is crucial for the prediction of malaria transmission and intervention impact. The human landing catch method is frequently used to directly measure estimate exposure rates; however, there has been an increasing shift from this method to exposure-free alternatives, such as the mosquito electrocuting traps (MET) and other approaches. While these latter methods can provide robust and representative values of human exposure and mosquito density, they often still require a human volunteer, which poses logistical challenges. Additionally, in the case of the MET, the early MET prototype (METe) required human volunteers to wear protective clothing that could be uncomfortable. We investigated two alternative trapping approaches to address these challenges by comparing the performance of the METe prototype to: (i) a modified caged MET prototype that offers full protection to users (METc) and (ii) a barrier screen trap (BST) designed to passively sample (host-seeking and blood-fed) mosquitoes outdoors without requiring a human participant. Methods The relative performance of the METe, METc and BST were evaluated in a 3 × 3 Latin square field experiment design conducted in south-eastern Tanzania over 12 nights of sampling. The outcomes of interest were the nightly catch of mosquitoes and biting time estimates. Results The METc and BST caught similar numbers of An. arabiensis as the METe (relative ratio [RR] = 0.76, 95% confidence interval [CI]: 0.42–1.39, P = 0.38 and RR = 1.13, 95% CI: 0.63–2.04, P = 0.69, respectively). Similarly, the METc and BST caught similar numbers of Culex spp. as the METe (RR = 0.87, 95% CI: 0.62–1.22, P = 0.42 and RR = 0.80, 95% CI: 0.57–1.12, P = 0.199, respectively). All three trapping methods indicated a similar pattern of biting activity by An. arabiensis and Culex spp., characterized by biting starting in the early evening (18:00–22:00), peaking when people are typically sleeping (22:00–05:00) and dropping off drastically toward the morning (05:00–07:00). Conclusions The modifications made to the METe design to improve user comfort and remove the need for protective clothing did not result in an underestimation of mosquito vector abundance nor misrepresentation of their biting time pattern. We recommend the METc for use over the METe design. Similarly, the BST demonstrated potential for monitoring malaria and filariasis vector densities in Tanzania. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05549-4.
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Ondeto BM, Wang X, Atieli H, Zhong D, Zhou G, Lee MC, Orondo PW, Ochwedo KO, Omondi CJ, Muriu SM, Odongo DO, Ochanda H, Kazura J, Githeko AK, Yan G. A prospective cohort study of Plasmodium falciparum malaria in three sites of Western Kenya. Parasit Vectors 2022; 15:416. [PMID: 36352453 PMCID: PMC9647947 DOI: 10.1186/s13071-022-05503-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 09/14/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Malaria in western Kenya is currently characterized by sustained high Plasmodial transmission and infection resurgence, despite positive responses in some areas following intensified malaria control interventions since 2006. This study aimed to evaluate long-term changes in malaria transmission profiles and to assess patterns of asymptomatic malaria infections in school children aged 5-15 years at three sites in western Kenya with heterogeneous malaria transmission and simultaneous malaria control interventions. METHODS The study was conducted from 2018 to 2019 and is based on data taken every third year from 2005 to 2014 during a longitudinal parasitological and mosquito adult surveillance and malaria control programme that was initiated in 2002 in the villages of Kombewa, Iguhu, and Marani. Plasmodium spp. infections were determined using microscopy. Mosquito samples were identified to species and host blood meal source and sporozoite infections were assayed using polymerase chain reaction. RESULTS Plasmodium falciparum was the only malaria parasite evaluated during this study (2018-2019). Asymptomatic malaria parasite prevalence in school children decreased in all sites from 2005 to 2008. However, since 2011, parasite prevalence has resurged by > 40% in Kombewa and Marani. Malaria vector densities showed similar reductions from 2005 to 2008 in all sites, rose steadily until 2014, and decreased again. Overall, Kombewa had a higher risk of infection compared to Iguhu (χ2 = 552.52, df = 1, P < 0.0001) and Marani (χ2 = 1127.99, df = 1, P < 0.0001). There was a significant difference in probability of non-infection during malaria episodes (log-rank test, χ2 = 617.59, df = 2, P < 0.0001) in the study sites, with Kombewa having the least median time of non-infection during malaria episodes. Gender bias toward males in infection was observed (χ2 = 27.17, df = 1, P < 0.0001). The annual entomological inoculation rates were 5.12, 3.65, and 0.50 infective bites/person/year at Kombewa, Iguhu, and Marani, respectively, during 2018 to 2019. CONCLUSIONS Malaria prevalence in western Kenya remains high and has resurged in some sites despite continuous intervention efforts. Targeting malaria interventions to those with asymptomatic infections who serve as human reservoirs might decrease malaria transmission and prevent resurgences. Longitudinal monitoring enables detection of changes in parasitological and entomological profiles and provides core baseline data for the evaluation of vector interventions and guidance for future planning of malaria control.
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Affiliation(s)
- Benyl M. Ondeto
- grid.10604.330000 0001 2019 0495Department of Biology, University of Nairobi, Nairobi, 00100 Kenya ,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya
| | - Xiaoming Wang
- grid.266093.80000 0001 0668 7243Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697 USA
| | - Harrysone Atieli
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya
| | - Daibin Zhong
- grid.266093.80000 0001 0668 7243Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697 USA
| | - Guofa Zhou
- grid.266093.80000 0001 0668 7243Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697 USA
| | - Ming-Chieh Lee
- grid.266093.80000 0001 0668 7243Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697 USA
| | - Pauline Winnie Orondo
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya ,grid.411943.a0000 0000 9146 7108Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, 00200 Kenya
| | - Kevin O. Ochwedo
- grid.10604.330000 0001 2019 0495Department of Biology, University of Nairobi, Nairobi, 00100 Kenya ,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya
| | - Collince J. Omondi
- grid.10604.330000 0001 2019 0495Department of Biology, University of Nairobi, Nairobi, 00100 Kenya ,Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya
| | - Simon M. Muriu
- grid.449370.d0000 0004 1780 4347Department of Biological Sciences, Pwani University, Kilifi, 80108 Kenya
| | - David O. Odongo
- grid.10604.330000 0001 2019 0495Department of Biology, University of Nairobi, Nairobi, 00100 Kenya
| | - Horace Ochanda
- grid.10604.330000 0001 2019 0495Department of Biology, University of Nairobi, Nairobi, 00100 Kenya
| | - James Kazura
- grid.67105.350000 0001 2164 3847Center for Global Health and Disease, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Andrew K. Githeko
- Sub-Saharan Africa International Center of Excellence for Malaria Research, Tom Mboya University, Homa Bay, 40300 Kenya ,grid.33058.3d0000 0001 0155 5938Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, 40100 Kenya
| | - Guiyun Yan
- grid.266093.80000 0001 0668 7243Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA 92697 USA
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Tomas T, Eligo N, Tamiru G, Massebo F. Outdoor and early hour human biting activities of malaria mosquitoes and the suitability of clay pot for outdoor resting mosquito collection in malaria endemic villages of southern Rift Valley, Ethiopia. Parasite Epidemiol Control 2022; 19:e00278. [PMID: 36345433 PMCID: PMC9636569 DOI: 10.1016/j.parepi.2022.e00278] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 08/21/2022] [Accepted: 10/26/2022] [Indexed: 11/07/2022] Open
Abstract
Background Sampling adult Anopheles mosquitoes is important for assessing vector density, estimating the sporozoite infection rate, and quantifying the impact of vector control interventions. The objective of this study was to assess the Anopheles mosquito species composition, and their outdoor and indoor biting activities, and to evaluate the suitability of clay pots for indoor and outdoor resting mosquito collections. Methods Two malaria-endemic villages in the Gamo zone were purposely selected. Forty clay pots were deployed for outdoor resting mosquitoes sampling and another forty for indoor resting sampling. Twenty pit shelters were constructed for outdoor resting mosquito collection. The human landing catch (HLC) technique was employed to collect indoor and outdoor host-seeking mosquitoes in two households in each village. Morphological identification of the Anopheles mosquito was done using an identification key. Enzyme-linked immunosorbent assay technique was used for blood meal origin and circumsporozoite proteins (CSP) test. Speciation of An. gambiae complex was done using polymerase chain reaction. A Chi-square test was used to compare the effectiveness of clay pot and pit shelters for outdoor resting sampling. Results A total of 904 female Anopheles mosquitoes comprising An. gambiae complex, An. pharoensis, An. tenebrosus, An. dencalicus and An. demelloni were sampled. The majority (64%) of them were sampled by the HLC technique. There was a slight difference between the outdoor clay pot (19%) and pit shelter (17%) collection. No Anopheles mosquitoes were collected indoor using clay pots. All mosquitoes were tested for CSPs, but none of them were found to be positive. Anopheles mosquitoes were tending to bite humans outdoor than indoors, and their peak biting hours was 10–11 pm. The human blood meal index of Anopheles mosquitoes was 0.07 from pit shelters and it was 0.04 from clay pots. The bovine blood meal index was 0.45 for mosquitoes from both pit shelters and clay pot collections. Conclusion Anopheles arabiensis was the predominant species and it was tending to bite cattle more than humans. Clay pot could be suitable for outdoor resting mosquito collection, but not for indoor resting species.
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Christofferson RC, Wearing HJ, Turner EA, Walsh CS, Salje H, Tran-Kiem C, Cauchemez S. How do i bite thee? let me count the ways: Exploring the implications of individual biting habits of Aedes aegypti for dengue transmission. PLoS Negl Trop Dis 2022; 16:e0010818. [PMID: 36194617 PMCID: PMC9565401 DOI: 10.1371/journal.pntd.0010818] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/14/2022] [Accepted: 09/15/2022] [Indexed: 11/26/2022] Open
Abstract
In models of mosquito-borne transmission, the mosquito biting rate is an influential parameter, and understanding the heterogeneity of the process of biting is important, as biting is usually assumed to be relatively homogeneous across individuals, with time-between-bites described by an exponentially distributed process. However, these assumptions have not been addressed through laboratory experimentation. We experimentally investigated the daily biting habits of Ae. aegypti at three temperatures (24°C, 28°C, and 32°C) and determined that there was individual heterogeneity in biting habits (number of bites, timing of bites, etc.). We further explored the consequences of biting heterogeneity using an individual-based model designed to examine whether a particular biting profile determines whether a mosquito is more or less likely to 1) become exposed given a single index case of dengue (DENV) and 2) transmit to a susceptible human individual. Our experimental results indicate that there is heterogeneity among individuals and among temperature treatments. We further show that this results in altered probabilities of transmission of DENV to and from individual mosquitoes based on biting profiles. While current model representation of biting may work under some conditions, it might not uniformly be the best fit for this process. Our data also confirm that biting is a non-monotonic process with temperatures around 28°C being optimum.
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Affiliation(s)
- Rebecca C. Christofferson
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America
- Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Helen J. Wearing
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
- Department of Mathematics and Statistics, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Erik A. Turner
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Christine S. Walsh
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Henrik Salje
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, Université Paris Cité, CNRS UMR 2000, Paris, France
| | - Cécile Tran-Kiem
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, Université Paris Cité, CNRS UMR 2000, Paris, France
- Collège Doctoral, Sorbonne Université, Paris, France
| | - Simon Cauchemez
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, Université Paris Cité, CNRS UMR 2000, Paris, France
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Fernandez Montoya L, Alafo C, Martí-Soler H, Máquina M, Comiche K, Cuamba I, Munguambe K, Cator L, Aide P, Galatas B, Cuamba N, Marrenjo D, Saúte F, Paaijmans KP. Overlaying human and mosquito behavioral data to estimate residual exposure to host-seeking mosquitoes and the protection of bednets in a malaria elimination setting where indoor residual spraying and nets were deployed together. PLoS One 2022; 17:e0270882. [PMID: 36107865 PMCID: PMC9477321 DOI: 10.1371/journal.pone.0270882] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 06/21/2022] [Indexed: 11/18/2022] Open
Abstract
Characterizing persistent malaria transmission that occurs after the combined deployment of indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) is critical to guide malaria control and elimination efforts. This requires a detailed understanding of both human and vector behaviors at the same temporal and spatial scale. Cross-sectional human behavior evaluations and mosquito collections were performed in parallel in Magude district, Mozambique. Net use and the exact time when participant moved into each of five environments (outdoor, indoor before bed, indoor in bed, indoor after getting up, and outdoor after getting up) were recorded for individuals from three different age groups and both sexes during a dry and a rainy season. Malaria mosquitoes were collected with CDC light traps in combination with collection bottle rotators. The percentage of residual exposure to host-seeking vectors that occurred in each environment was calculated for five local malaria vectors with different biting behaviors, and the actual (at observed levels of LLIN use) and potential (i.e. if all residents had used an LLIN) personal protection conferred by LLINs was estimated. Anopheles arabiensis was responsible for more than 74% of residents' residual exposure to host-seeking vectors during the Magude project. The other four vector species (An. funestus s.s., An. parensis, An. squamosus and An. merus) were responsible for less than 10% each. The personal protection conferred by LLINs prevented only 39.2% of the exposure to host-seeking vectors that survived the implementation of both IRS and LLINs, and it differed significantly across seasons, vector species and age groups. At the observed levels of bednet use, 12.5% of all residual exposure to host-seeking vectors occurred outdoor during the evening, 21.9% indoor before going to bed, almost two thirds (64%) while people were in bed, 1.4% indoors after getting up and 0.2% outdoor after leaving the house. Almost a third of the residual exposure to host-seeking vectors (32.4%) occurred during the low transmission season. The residual bites of An. funestus s.s. and An. parensis outdoors and indoor before bedtime, of An. arabiensis indoors when people are in bed, and of An. squamosus both indoors and outdoors, are likely to have sustained malaria transmission throughout the Magude project. By increasing LLIN use, an additional 24.1% of exposure to the remaining hosts-seeking vectors could have been prevented. Since An. arabiensis, the most abundant vector, feeds primarily while people are in bed, increasing net use and net feeding inhibition (through e.g. community awareness activities and the selection of more effective LLINs) could significantly reduce the exposure to remaining host-seeking mosquitoes. Nonetheless, supplementary interventions aiming to reduce human-vector contact outdoors and/or indoors before people go to bed (e.g. through larval source management, window and eave screening, eave tubes, and spatial repellents) will be needed to reduce residual exposure to the outdoor and early biting An. funestus s.s. and An. parensis.
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Affiliation(s)
- Lucia Fernandez Montoya
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Celso Alafo
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
- Goodbye Malaria, Tchau Tchau Malaria Foundation, Chibungo, Mozambique
| | | | - Mara Máquina
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Kiba Comiche
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Inocencia Cuamba
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Khatia Munguambe
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | | | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
- Instituto Nacional da Saúde, Ministério da Saúde, Maputo, Mozambique
| | - Beatriz Galatas
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Nelson Cuamba
- Programa Nacional de Controlo da Malária, Ministério da Saúde, Maputo, Mozambique
- PMI VectorLink Project, Abt Associates Inc., Maputo, Mozambique
| | - Dulcisaria Marrenjo
- Programa Nacional de Controlo da Malária, Ministério da Saúde, Maputo, Mozambique
| | - Francisco Saúte
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
| | - Krijn P. Paaijmans
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Fundação Manhiça, Mozambique
- Center for Evolution and Medicine, School of Life Sciences, Arizona State University, Tempe, AZ, United States of America
- The Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, AZ, United States of America
- Simon A. Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, AZ, United States of America
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Ngowo HS, Limwagu AJ, Ferguson HM, Matthiopoulos J, Okumu FO, Nelli L. A statistical calibration tool for methods used to sample outdoor-biting mosquitoes. Parasit Vectors 2022; 15:293. [PMID: 35978415 PMCID: PMC9386948 DOI: 10.1186/s13071-022-05403-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 07/19/2022] [Indexed: 11/25/2022] Open
Abstract
Background Improved methods for sampling outdoor-biting mosquitoes are urgently needed to improve surveillance of vector-borne diseases. Such tools could potentially replace the human landing catch (HLC), which, despite being the most direct option for measuring human exposures, raises significant ethical and logistical concerns. Several alternatives are under development, but detailed evaluation still requires common frameworks for calibration relative to HLC. The aim of this study was to develop and validate a statistical framework for predicting human-biting rates from different exposure-free alternatives. Methods We obtained mosquito abundance data (Anopheles arabiensis, Anopheles funestus and Culex spp.) from a year-long Tanzanian study comparing six outdoor traps [Suna Trap (SUN), BG Sentinel (BGS), M-Trap (MTR), M-Trap + CDC (MTRC), Ifakara Tent Trap-C (ITT-C) and Mosquito Magnet-X Trap (MMX)] and HLC. Generalised linear models were developed within a Bayesian framework to investigate associations between the traps and HLC, taking intra- and inter-specific density dependence into account. The best model was used to create a calibration tool for predicting HLC-equivalents. Results For An. arabiensis, SUN catches had the strongest correlation with HLC (R2 = 19.4), followed by BGS (R2 = 17.2) and MTRC (R2 = 13.1) catches. The least correlated catch was MMX (R2 = 2.5). For An. funestus, BGS had the strongest correlation with the HLC (R2 = 53.4), followed by MTRC (R2 = 37.4) and MTR (R2 = 37.4). For Culex mosquitoes, the traps most highly correlated with the HLC were MTR (R2 = 45.4) and MTRC (R2 = 44.2). Density dependence, both between and within species, influenced the performance of only BGS traps. An interactive Shiny App calibration tool was developed for this and similar applications. Conclusion We successfully developed a calibration tool to assess the performance of different traps for assessing outdoor-biting risk, and established a valuable framework for estimating human exposures based on the trap catches. The performance of candidate traps varied between mosquito taxa; thus, there was no single optimum. Although all the traps tested underestimated the HLC-derived exposures, it was possible to mathematically define their representativeness of the true biting risk, with or without density dependence. The results of this study emphasise the need to aim for a consistent and representative sampling approach, as opposed to simply seeking traps that catch the most mosquitoes. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05403-7.
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Affiliation(s)
- Halfan S Ngowo
- Department of Environmental Health & Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania. .,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.
| | - Alex J Limwagu
- Department of Environmental Health & Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania
| | - Heather M Ferguson
- Department of Environmental Health & Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Jason Matthiopoulos
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Fredros O Okumu
- Department of Environmental Health & Ecological Sciences, Ifakara Health Institute, Ifakara, Tanzania.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.,School of Public Health, University of the Witwatersrand, Johannesburg, Republic of South Africa.,School of Life Science and Bioengineering, Nelson Mandela African Institution of Science & Technology, Arusha, Tanzania
| | - Luca Nelli
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
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Mgaya JN, Siria DJ, Makala FE, Mgando JP, Vianney JM, Mwanga EP, Okumu FO. Effects of sample preservation methods and duration of storage on the performance of mid-infrared spectroscopy for predicting the age of malaria vectors. Parasit Vectors 2022; 15:281. [PMID: 35933384 PMCID: PMC9356448 DOI: 10.1186/s13071-022-05396-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/09/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Monitoring the biological attributes of mosquitoes is critical for understanding pathogen transmission and estimating the impacts of vector control interventions on the survival of vector species. Infrared spectroscopy and machine learning techniques are increasingly being tested for this purpose and have been proven to accurately predict the age, species, blood-meal sources, and pathogen infections in Anopheles and Aedes mosquitoes. However, as these techniques are still in early-stage implementation, there are no standardized procedures for handling samples prior to the infrared scanning. This study investigated the effects of different preservation methods and storage duration on the performance of mid-infrared spectroscopy for age-grading females of the malaria vector, Anopheles arabiensis. METHODS Laboratory-reared An. arabiensis (N = 3681) were collected at 5 and 17 days post-emergence, killed with ethanol, and then preserved using silica desiccant at 5 °C, freezing at - 20 °C, or absolute ethanol at room temperature. For each preservation method, the mosquitoes were divided into three groups, stored for 1, 4, or 8 weeks, and then scanned using a mid-infrared spectrometer. Supervised machine learning classifiers were trained with the infrared spectra, and the support vector machine (SVM) emerged as the best model for predicting the mosquito ages. RESULTS The model trained using silica-preserved mosquitoes achieved 95% accuracy when predicting the ages of other silica-preserved mosquitoes, but declined to 72% and 66% when age-classifying mosquitoes preserved using ethanol and freezing, respectively. Prediction accuracies of models trained on samples preserved in ethanol and freezing also reduced when these models were applied to samples preserved by other methods. Similarly, models trained on 1-week stored samples had declining accuracies of 97%, 83%, and 72% when predicting the ages of mosquitoes stored for 1, 4, or 8 weeks respectively. CONCLUSIONS When using mid-infrared spectroscopy and supervised machine learning to age-grade mosquitoes, the highest accuracies are achieved when the training and test samples are preserved in the same way and stored for similar durations. However, when the test and training samples were handled differently, the classification accuracies declined significantly. Protocols for infrared-based entomological studies should therefore emphasize standardized sample-handling procedures and possibly additional statistical procedures such as transfer learning for greater accuracy.
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Affiliation(s)
- Jacqueline N Mgaya
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.
- School of Life Science and Bioengineering, The Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania.
| | - Doreen J Siria
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Faraja E Makala
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - Joseph P Mgando
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania
| | - John-Mary Vianney
- School of Life Science and Bioengineering, The Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania
| | - Emmanuel P Mwanga
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.
- Institute of Biodiversity, Animal Health, and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Fredros O Okumu
- Environmental Health and Ecological Science Department, Ifakara Health Institute, P.O. Box 53, Ifakara, Tanzania.
- School of Life Science and Bioengineering, The Nelson Mandela African Institute of Science and Technology, P.O. Box 447, Arusha, Tanzania.
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
- Institute of Biodiversity, Animal Health, and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.
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Krezanoski PJ, Rek J, Musiime A, Otto G, Kyagamba P, Rwatooro JA, Walters K, Romanel A, Arinaitwe E, Nankabirwa JI, Drakeley CJ, Kamya M, Dorsey G. Remote bednet use monitoring to describe patterns of use and exposure to female Anopheles mosquitoes in an Ugandan cohort. FRONTIERS IN EPIDEMIOLOGY 2022; 2:934557. [PMID: 37854770 PMCID: PMC10583855 DOI: 10.3389/fepid.2022.934557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/13/2022] [Indexed: 10/20/2023]
Abstract
Background Long lasting insecticide-treated bednets (LLINs) are the most widely used tool for preventing malaria. There has been a plateau in progress in the highest burden African countries since 2015, leading to questions about the effectiveness of LLINs. In this study, remote LLIN use monitors were deployed in a cohort in Eastern Uganda to explore how LLIN use interacts with mosquito exposure. Methods The SmartNet study included 20 households from May to October 2019. SmartNet devices recorded, every 15 min, whether an LLIN was unfurled or folded up. Unannounced visits were used to assess SmartNet accuracy. Risk factors associated with poor LLIN use were assessed using generalized linear equations. Female Anopheles exposure was estimated by combining hourly probabilities of exposure from human landing catches and measures of density from biweekly CDC light traps in participants rooms. Mosquito exposure averted by LLINs was quantified using SmartNet measurements and age-related differences were estimated using generalized linear equations, adjusting for relevant covariates and household clustering. Results 96 individuals contributed 5,640 SmartNet observation nights. In 126 unannounced visits, SmartNet had an area under the curve of 0.869 in classifying whether the LLIN was up or down. The rate of non-use was 13.5% of nights (95% CI: 12.6-14.3%). Compared to children under 5, non-use was 1.8 times higher (95% CI: 1.6-2.1; p < 0.001) in children 5-15 years and 2.6 times higher (95% CI: 2.2-3.1; p < 0.001) in participants aged 15-<30years. There was no difference between children under 5 years and adults > 30 years. LLIN use averted 50.3% of female Anopheles mosquito exposure (95% CI: 40.0-60.0%), with decreasing point estimates of efficacy across age groups: from 61.7% (95% CI: 42.6-80.7%) in children under 5 years to 48.0% (95% CI: 29.1-66.8%) in adults over 30. Conclusions Objective monitors are accurate and can feasibly be deployed to obtain data about LLIN use. LLINs provided protection from only 50% of female Anopheles mosquito exposure in this cohort and protection was dependent upon age. In assessing the role of LLINs in malaria prevention it is crucial to consider the dynamics between mosquito exposure and LLIN use behaviors.
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Affiliation(s)
- Paul J. Krezanoski
- University of California, San Francisco, San Francisco, CA, United States
- Opportunity Solutions International, San Francisco, CA, United States
| | - John Rek
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | - Alex Musiime
- US President's Malaria Initiative, Kampala, Uganda
| | - Geoffrey Otto
- Infectious Diseases Research Collaboration, Kampala, Uganda
| | | | | | - Kelly Walters
- University of California, San Francisco, San Francisco, CA, United States
| | - Alina Romanel
- University of California, San Francisco, San Francisco, CA, United States
| | | | - Joaniter I. Nankabirwa
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Makerere University College of Health Sciences, Kampala, Uganda
| | - Chris J. Drakeley
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Moses Kamya
- Infectious Diseases Research Collaboration, Kampala, Uganda
- Makerere University College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- University of California, San Francisco, San Francisco, CA, United States
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Mapua SA, Hape EE, Kihonda J, Bwanary H, Kifungo K, Kilalangongono M, Kaindoa EW, Ngowo HS, Okumu FO. Persistently high proportions of plasmodium-infected Anopheles funestus mosquitoes in two villages in the Kilombero valley, South-Eastern Tanzania. Parasite Epidemiol Control 2022; 18:e00264. [PMID: 35959316 PMCID: PMC9357827 DOI: 10.1016/j.parepi.2022.e00264] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 06/20/2022] [Accepted: 07/29/2022] [Indexed: 11/04/2022] Open
Abstract
Background In south-eastern Tanzania where insecticide-treated nets have been widely used for >20 years, malaria transmission has greatly reduced but remains highly heterogenous over small distances. This study investigated the seasonal prevalence of Plasmodium sporozoite infections in the two main malaria vector species, Anopheles funestus and Anopheles arabiensis for 34 months, starting January 2018 to November 2020. Methods Adult mosquitoes were collected using CDC-light traps and Prokopack aspirators inside local houses in Igumbiro and Sululu villages, where earlier surveys had found very high densities of An. funestus. Collected females were sorted by taxa, and the samples examined using ELISA assays for detecting Plasmodium circumsporozoite protein in their salivary glands. Results Of 7859 An. funestus tested, 4.6% (n = 365) were positive for Pf sporozoites in the salivary glands. On the contrary, only 0.4% (n = 9) of the 2382 An. arabiensis tested were positive. The sporozoite prevalence did not vary significantly between the villages or seasons. Similarly, the proportions of parous females of either species were not significantly different between the two villages (p > 0.05) but was slightly higher in An. funestus (0.50) than in An. arabiensis (0.42). Analysis of the 2020 data determined that An. funestus contributed 97.7% of all malaria transmitted in households in these two villages. Conclusions In contexts where individual vector species mediate most of the pathogen transmission, it may be most appropriate to pursue a species-focused approach to better understand the ecology of the dominant vectors and target them with effective interventions to suppress transmission. Despite the ongoing efforts on tackling malaria in the two study villages, there is still persistently high Plasmodium infection prevalence in local populations of An. funestus, which now carry ~97% of all malaria infections and mediates intense year-round transmission. Further reduction in malaria burden in these or other similar settings requires effective targeting of An. funestus.
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Mponzi WP, Swai JK, Kaindoa EW, Kifungo K, Eiras AE, Batista EPA, Matowo NS, Sangoro PO, Finda MF, Mmbando AS, Gavana T, Ngowo HS, Okumu FO. Observing the distribution of mosquito bites on humans to inform personal protection measures against malaria and dengue vectors. PLoS One 2022; 17:e0271833. [PMID: 35877666 PMCID: PMC9312397 DOI: 10.1371/journal.pone.0271833] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 07/07/2022] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Understanding mosquito biting behaviours is important for designing and evaluating protection methods against nuisance biting and mosquito-borne diseases (e.g. dengue, malaria and zika). We investigated the preferred biting sites by Aedes aegypti and Anopheles arabiensis on adult volunteers in standing or sleeping positions; and estimated the theoretical protection limits affordable from protective clothing or repellent-treated footwear. METHODS Adult volunteers dressed in shorts and t-shirts were exposed to infection-free laboratory-reared mosquitoes inside screened chambers from 6am to noon (for day-biting Ae. aegypti) or 6pm to midnight (night-biting An. arabiensis). Attempted bites on different body parts were recorded. Comparative observations were made on same volunteers while wearing sandals treated with transfluthrin, a vapour-phase pyrethroid that kills and repels mosquitoes. RESULTS An. arabiensis bites were mainly on the lower limbs of standing volunteers (95.9% of bites below the knees) but evenly-distributed over all exposed body surfaces when the volunteers were on sleeping positions (only 28.8% bites below knees). Ae. aegypti bites were slightly concentrated on lower limbs of standing volunteers (47.7% below knees), but evenly-distributed on sleeping volunteers (23.3% below knees). Wearing protective clothing that leave only hands and head uncovered (e.g. socks + trousers + long-sleeved shirts) could theoretically prevent 78-83% of bites during sleeping, and at least 90% of bites during non-sleeping hours. If the feet are also exposed, protection declines to as low as 36.3% against Anopheles. The experiments showed that transfluthrin-treated sandals reduced An. arabiensis by 54-86% and Ae. aegypti by 32-39%, but did not change overall distributions of bites. CONCLUSION Biting by An. arabiensis and Ae. aegypti occur mainly on the lower limbs, though this proclivity is less pronounced in the Aedes species. However, when hosts are on sleeping positions, biting by both species is more evenly-distributed over the exposed body surfaces. High personal protection might be achieved by simply wearing long-sleeved clothing, though protection against Anopheles particularly requires covering of feet and lower legs. The transfluthrin-treated footwear can reduce biting risk, especially by An. arabiensis. These findings could inform the design and use of personal protection tools (both insecticidal and non-insecticidal) against mosquitoes and mosquito-borne diseases.
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Affiliation(s)
- Winifrida P. Mponzi
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Johnson K. Swai
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Emmanuel W. Kaindoa
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- The Nelson Mandela, African Institution of Science and Technology, School of Life Sciences and Bio Engineering, Arusha, United Republic of Tanzania
| | - Khamis Kifungo
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Alvaro E. Eiras
- Department of Parasitology, Laboratory of Technological Innovation of Vectors Control, Biological Sciences Institute, Federal University of Minas Gerais Belo Horizontal Brazil, Belo Horizonte, Brazil
| | - Elis P. A. Batista
- Department of Parasitology, Laboratory of Technological Innovation of Vectors Control, Biological Sciences Institute, Federal University of Minas Gerais Belo Horizontal Brazil, Belo Horizonte, Brazil
| | - Nancy S. Matowo
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Peter O. Sangoro
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Marceline F. Finda
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Arnold S. Mmbando
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Tegemeo Gavana
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Halfan S. Ngowo
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, United Kingdom
| | - Fredros O. Okumu
- Environmental Health and Ecological Science Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- The Nelson Mandela, African Institution of Science and Technology, School of Life Sciences and Bio Engineering, Arusha, United Republic of Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, United Kingdom
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Naserrudin NA, Culleton R, Hod R, Saffree Jeffree M, Ahmed K, Hassan MR. Exploring the key anthropological drivers of and barriers to zoonotic malaria preventative behaviour in a community exposed to Plasmodium knowlesi infection in Malaysia: protocol for a qualitative study with a participatory research design. BMJ Open 2022; 12:e060866. [PMID: 35772825 PMCID: PMC9247694 DOI: 10.1136/bmjopen-2022-060866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
INTRODUCTION Plasmodium knowlesi malaria is a zoonotic mosquito-borne disease with complex epidemiology. According to the WHO, the prevention and control of vector-borne diseases require community participation to increase coherence between malaria interventions and sustainable public health programmes. We describe a participatory research (PR) design for a study aimed at exploring the key anthropological drivers of and barriers to zoonotic malaria preventive behaviour among communities exposed to P. knowlesi infection in Malaysia. Participatory approaches can facilitate policymakers in designing future zoonotic malaria control programmes by investigating community perspectives and concerns about zoonotic malaria in a local context. METHODS AND ANALYSIS The PR will be conducted over a period of 12 months, from March 2022 to March 2023, among adults (>18 years old) who are permanent residents in a rural village exposed to P. knowlesi malaria in Sabah, Malaysia. We will select patients who were diagnosed with P. knowlesi infection from January to December 2021 for focus group discussions (FGDs), as they can provide perspectives on the disease from the point of view of those previously diagnosed with infection. In-depth interviews (IDIs) with people of importance in the community, such as village heads, will also be conducted. Both FGDs and IDIs will be conducted from March 2022 until June 2022. Concurrently, a photovoice with adults over 18 years old who reside in the community will be conducted. The target sample sizes for FGDs, IDIs and photovoice are 6-8, 12 and 10-15 participants, respectively. We will use a study framework as a theoretical lens to guide the exploration of the beliefs, social contexts, barriers and drivers surrounding zoonotic malaria preventive behaviour. ETHICS AND DISSEMINATION This study has been approved by the Medical Research and Ethics Committee Ministry of Health Malaysia (NMRR ID-21-01980-JEH) and the Research and Innovation Secretariat, Faculty of Medicine, Universiti Kebangsaan Malaysia (FF-2021-462). All participants will provide consent prior to participation. The results will be reported in international peer-reviewed journals and presented at conferences and on other platforms.
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Affiliation(s)
- Nurul Athirah Naserrudin
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Kuala Lumpur, Malaysia
| | - Richard Culleton
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Rozita Hod
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Kuala Lumpur, Malaysia
| | - Mohammad Saffree Jeffree
- Public Health Medicine Department, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Kamruddin Ahmed
- Department of Pathology and Microbiology, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
- Borneo Medical and Health Research Centre, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia
| | - Mohd Rohaizat Hassan
- Department of Community Health, Faculty of Medicine, Universiti Kebangsaan Malaysia, Bangi, Kuala Lumpur, Malaysia
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Namango IH, Marshall C, Saddler A, Ross A, Kaftan D, Tenywa F, Makungwa N, Odufuwa OG, Ligema G, Ngonyani H, Matanila I, Bharmal J, Moore J, Moore SJ, Hetzel MW. The Centres for Disease Control light trap (CDC-LT) and the human decoy trap (HDT) compared to the human landing catch (HLC) for measuring Anopheles biting in rural Tanzania. Malar J 2022; 21:181. [PMID: 35690745 PMCID: PMC9188237 DOI: 10.1186/s12936-022-04192-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 05/20/2022] [Indexed: 11/10/2022] Open
Abstract
Background Vector mosquito biting intensity is an important measure to understand malaria transmission. Human landing catch (HLC) is an effective but labour-intensive, expensive, and potentially hazardous entomological surveillance tool. The Centres for Disease Control light trap (CDC-LT) and the human decoy trap (HDT) are exposure-free alternatives. This study compared the CDC-LT and HDT against HLC for measuring Anopheles biting in rural Tanzania and assessed their suitability as HLC proxies. Methods Indoor mosquito surveys using HLC and CDC-LT and outdoor surveys using HLC and HDT were conducted in 2017 and in 2019 in Ulanga, Tanzania in 19 villages, with one trap/house/night. Species composition, sporozoite rates and density/trap/night were compared. Aggregating the data by village and month, the Bland–Altman approach was used to assess agreement between trap types. Results Overall, 66,807 Anopheles funestus and 14,606 Anopheles arabiensis adult females were caught with 6,013 CDC-LT, 339 indoor-HLC, 136 HDT and 195 outdoor-HLC collections. Indoors, CDC-LT caught fewer An. arabiensis (Adjusted rate ratio [Adj.RR] = 0.35, 95% confidence interval [CI]: 0.27–0.46, p < 0.001) and An. funestus (Adj.RR = 0.63, 95%CI: 0.51–0.79, p < 0.001) than HLC per trap/night. Outdoors, HDT caught fewer An. arabiensis (Adj.RR = 0.04, 95%CI: 0.01–0.14, p < 0.001) and An. funestus (Adj.RR = 0.10, 95%CI: 0.07–0.15, p < 0.001) than HLC. The bias and variability in number of mosquitoes caught by the different traps were dependent on mosquito densities. The relative efficacies of both CDC-LT and HDT in comparison to HLC declined with increased mosquito abundance. The variability in the ratios was substantial for low HLC counts and decreased as mosquito abundance increased. The numbers of sporozoite positive mosquitoes were low for all traps. Conclusions CDC-LT can be suitable for comparing mosquito populations between study arms or over time if accuracy in the absolute biting rate, compared to HLC, is not required. CDC-LT is useful for estimating sporozoite rates because large numbers of traps can be deployed to collect adequate mosquito samples. The present design of the HDT is not amenable for use in large-scale entomological surveys. Use of HLC remains important for estimating human exposure to mosquitoes as part of estimating the entomological inoculation rate (EIR). Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04192-9.
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Affiliation(s)
- Isaac Haggai Namango
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland. .,University of Basel, Basel, Switzerland. .,Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.
| | - Carly Marshall
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.,British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada
| | - Adam Saddler
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.,Telethon Kids Institute, Perth, Australia
| | - Amanda Ross
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland
| | - David Kaftan
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.,New York University Grossman School of Medicine, New York, NY, USA
| | - Frank Tenywa
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Noely Makungwa
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Olukayode G Odufuwa
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland.,Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.,London School of Hygiene and Tropical Medicine, London, UK
| | - Godfrey Ligema
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Hassan Ngonyani
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Isaya Matanila
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Jameel Bharmal
- Innovative Vector Control Consortium, Dar es Salaam, Tanzania
| | - Jason Moore
- Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Sarah J Moore
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland.,Vector Control Product Testing Unit, Ifakara Health Institute, Bagamoyo, Tanzania.,Nelson Mandela African Institute of Science and Technology, Arusha, Tanzania
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.,University of Basel, Basel, Switzerland
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Rae JD, Nosten S, Kajeechiwa L, Wiladphaingern J, Parker DM, Landier J, Thu AM, Dah H, Be A, Cho WC, Paw K, Paw ES, Shee PB, Poe C, Nu C, Nyaw B, Simpson JA, Devine A, Maude RJ, Moo KL, Min MC, Thwin MM, Tun SW, Nosten FH. Surveillance to achieve malaria elimination in eastern Myanmar: a 7-year observational study. Malar J 2022; 21:175. [PMID: 35672747 PMCID: PMC9171744 DOI: 10.1186/s12936-022-04175-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 05/05/2022] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND The collection and utilization of surveillance data is essential in monitoring progress towards achieving malaria elimination, in the timely response to increases in malaria case numbers and in the assessment of programme functioning. This paper describes the surveillance activities used by the malaria elimination task force (METF) programme which operates in eastern Myanmar, and provides an analysis of data collected from weekly surveillance, case investigations, and monitoring and evaluation of programme performance. METHODS This retrospective analysis was conducted using data collected from a network of 1250 malaria posts operational between 2014 and 2021. To investigate changes in data completeness, malaria post performance, malaria case numbers, and the demographic details of malaria cases, summary statistics were used to compare data collected over space and time. RESULTS In the first 3 years of the METF programme, improvements in data transmission routes resulted in a 18.9% reduction in late reporting, allowing for near real-time analysis of data collected at the malaria posts. In 2020, travel restrictions were in place across Karen State in response to COVID-19, and from February 2021 the military coup in Myanmar resulted in widescale population displacement. However, over that period there has been no decline in malaria post attendance, and the majority of consultations continue to occur within 48 h of fever onset. Case investigations found that 43.8% of cases travelled away from their resident village in the 3 weeks prior to diagnosis and 36.3% reported never using a bed net whilst sleeping in their resident village, which increased to 72.2% when sleeping away from their resident village. Malaria post assessments performed in 82.3% of the METF malaria posts found malaria posts generally performed to a high standard. CONCLUSIONS Surveillance data collected by the METF programme demonstrate that despite significant changes in the context in which the programme operates, malaria posts have remained accessible and continue to provide early diagnosis and treatment contributing to an 89.3% decrease in Plasmodium falciparum incidence between 2014 and 2021.
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Affiliation(s)
- Jade D. Rae
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Suphak Nosten
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Ladda Kajeechiwa
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Jacher Wiladphaingern
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Daniel M. Parker
- Population Health and Disease Prevention, University of California-Irvine, Irvine, CA USA
- Epidemiology and Biostatistics, University of California-Irvine, Irvine, CA USA
| | - Jordi Landier
- IRD (Institut de Recherche Pour Le Developpement), Aix Marseille Univ, INSERM, SESSTIM, Aix Marseille Institute of Public Health, ISSPAM, Marseille, France
| | - Aung Myint Thu
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Hsa Dah
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Aye Be
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Win Cho Cho
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - K.’Nyaw Paw
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Eh Shee Paw
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Paw Bway Shee
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Christ Poe
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Chit Nu
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Baw Nyaw
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Julie A. Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
| | - Angela Devine
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, Australia
| | - Richard J. Maude
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Harvard TH Chan School of Public Health, Harvard University, Boston, USA
- The Open University, Milton Keynes, UK
| | - Ku Ler Moo
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Myo Chit Min
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - May Myo Thwin
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - Saw Win Tun
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | - François H. Nosten
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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Kahamba NF, Finda M, Ngowo HS, Msugupakulya BJ, Baldini F, Koekemoer LL, Ferguson HM, Okumu FO. Using ecological observations to improve malaria control in areas where Anopheles funestus is the dominant vector. Malar J 2022; 21:158. [PMID: 35655190 PMCID: PMC9161514 DOI: 10.1186/s12936-022-04198-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/19/2022] [Indexed: 11/10/2022] Open
Abstract
The most important malaria vectors in sub-Saharan Africa are Anopheles gambiae, Anopheles arabiensis, Anopheles funestus, and Anopheles coluzzii. Of these, An. funestus presently dominates in many settings in east and southern Africa. While research on this vector species has been impeded by difficulties in creating laboratory colonies, available evidence suggests it has certain ecological vulnerabilities that could be strategically exploited to greatly reduce malaria transmission in areas where it dominates. This paper examines the major life-history traits of An. funestus, its aquatic and adult ecologies, and its responsiveness to key interventions. It then outlines a plausible strategy for reducing malaria transmission by the vector and sustaining the gains over the medium to long term. To illustrate the propositions, the article uses data from south-eastern Tanzania where An. funestus mediates over 85% of malaria transmission events and is highly resistant to key public health insecticides, notably pyrethroids. Both male and female An. funestus rest indoors and the females frequently feed on humans indoors, although moderate to high degrees of zoophagy can occur in areas with large livestock populations. There are also a few reports of outdoor-biting by the species, highlighting a broader range of behavioural phenotypes that can be considered when designing new interventions to improve vector control. In comparison to other African malaria vectors, An. funestus distinctively prefers permanent and semi-permanent aquatic habitats, including river streams, ponds, swamps, and spring-fed pools. The species is therefore well-adapted to sustain its populations even during dry months and can support year-round malaria transmission. These ecological features suggest that highly effective control of An. funestus could be achieved primarily through strategic combinations of species-targeted larval source management and high quality insecticide-based methods targeting adult mosquitoes in shelters. If done consistently, such an integrated strategy has the potential to drastically reduce local populations of An. funestus and significantly reduce malaria transmission in areas where this vector species dominates. To sustain the gains, the programmes should be complemented with gradual environmental improvements such as house modification to maintain biting exposure at a bare minimum, as well as continuous engagements of the resident communities and other stakeholders.
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Affiliation(s)
- Najat F Kahamba
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania.
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, G128QQ, Glasgow, UK.
| | - Marceline Finda
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- School of Public Health, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Halfan S Ngowo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, G128QQ, Glasgow, UK
| | - Betwel J Msugupakulya
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Francesco Baldini
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, G128QQ, Glasgow, UK
| | - Lizette L Koekemoer
- Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Heather M Ferguson
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, G128QQ, Glasgow, UK
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania.
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, G128QQ, Glasgow, UK.
- School of Public Health, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa.
- School of Life Science and Biotechnology, Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha, Tanzania.
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47
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Lusiyana N, Ahdika A. Evaluating recurrent episodes of malaria incidence in Timika, Indonesia, through a Markovian multiple-state model. Infect Dis Model 2022; 7:261-276. [PMID: 35754556 PMCID: PMC9201011 DOI: 10.1016/j.idm.2022.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 03/30/2022] [Accepted: 05/31/2022] [Indexed: 10/27/2022] Open
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The Role of Human Behavior in Plasmodium knowlesi Malaria Infection: A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19063675. [PMID: 35329359 PMCID: PMC8953169 DOI: 10.3390/ijerph19063675] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 12/22/2022]
Abstract
Objectives: Plasmodium knowlesi is a non-human parasite that causes zoonotic disease in humans. This systematic review aims to highlight and summarize studies describing human behaviors and activities that expose humans to mosquito bites. Design: English entries in PubMed, Web of Science, and Science Direct from 2010 to 2020 were systematically perused, and the results were synthesized. Methodological quality was assessed using the Joanna Briggs Institute quality appraisal checklists. Setting: Studies that described malaria preventive measures were included. Laboratory, in vivo, in vitro, and animal studies were excluded. Primary and secondary outcome measures: The main outcome of the review was findings from studies describing the behavior that exposed a person or a group to P. knowlesi infection. Results: Twelve eligible studies were of good or medium quality. Attitude, disease misconceptions, perceived threat of disease, lack of motivation, and supernatural or traditional beliefs causing individuals to seek treatment from traditional healers influenced the exposure of individuals or communities to P. knowlesi malaria. Other factors were forestry activities (2.48, 1.45–4.23,95% CI, p = 0.0010) and sleeping outdoors (3.611, 1.48–8.85, 95% CI, p = 0.0049). Conclusions: Future studies must consider the importance of human behavior and community perspective on the infection to provide novel information to improve the current zoonotic malaria programs. Policymakers should concentrate on understanding human behavior and activities that expose individuals or communities to mosquito bites, in order to better design socially feasible interventions.
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49
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Mmbando AS, Bradley J, Kazimbaya D, Kasubiri R, Knudsen J, Siria D, von Seidlein L, Okumu FO, Lindsay SW. The effect of light and ventilation on house entry by Anopheles arabiensis sampled using light traps in Tanzania: an experimental hut study. Malar J 2022; 21:36. [PMID: 35123497 PMCID: PMC8818140 DOI: 10.1186/s12936-022-04063-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 01/26/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
In sub-Saharan Africa, house design and ventilation affects the number of malaria mosquito vectors entering houses. This study hypothesized that indoor light from a CDC-light trap, visible from outside a hut, would increase entry of Anopheles arabiensis, an important malaria vector, and examined whether ventilation modifies this effect.
Methods
Four inhabited experimental huts, each situated within a large chamber, were used to assess how light and ventilation affect the number of hut-entering mosquitoes in Tanzania. Each night, 300 female laboratory-reared An. arabiensis were released inside each chamber for 72 nights. Nightly mosquito collections were made using light traps placed indoors. Temperature and carbon dioxide concentrations were measured using data loggers. Treatments and sleepers were rotated between huts using a randomized block design.
Results
When indoor light was visible outside the huts, there was an 84% increase in the odds of collecting mosquitoes indoors (Odds ratio, OR = 1.84, 95% confidence intervals, 95% CI 1.74–1.95, p < 0.001) compared with when it was not. Although the odds of collecting mosquitoes in huts with closed eaves (OR = 0.54, 95% CI 0.41–0.72, p < 0.001) was less than those with open eaves, few mosquitoes entered either type of well-ventilated hut. The odds of collecting mosquitoes was 99% less in well-ventilated huts, compared with poorly-ventilated traditional huts (OR = 0.01, 95% CI 0.01–0.03, p < 0.001). In well-ventilated huts, indoor temperatures were 1.3 °C (95% CI 0.9–1.7, p < 0.001) cooler, with lower carbon dioxide (CO2) levels (mean difference = 97 ppm, 77.8–116.2, p < 0.001) than in poorly-ventilated huts.
Conclusion
Although light visible from outside a hut increased mosquito house entry, good natural ventilation reduces indoor carbon dioxide concentrations, a major mosquito attractant, thereby reducing mosquito-hut entry.
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50
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Okiring J, Epstein A, Namuganga JF, Kamya EV, Nabende I, Nassali M, Sserwanga A, Gonahasa S, Muwema M, Kiwuwa SM, Staedke SG, Kamya MR, Nankabirwa JI, Briggs J, Jagannathan P, Dorsey G. Gender difference in the incidence of malaria diagnosed at public health facilities in Uganda. Malar J 2022; 21:22. [PMID: 35062952 PMCID: PMC8778495 DOI: 10.1186/s12936-022-04046-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 01/11/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Routine malaria surveillance data in Africa primarily come from public health facilities reporting to national health management information systems. Although information on gender is routinely collected from patients presenting to these health facilities, stratification of malaria surveillance data by gender is rarely done. This study evaluated gender difference among patients diagnosed with parasitological confirmed malaria at public health facilities in Uganda. METHODS This study utilized individual level patient data collected from January 2020 through April 2021 at 12 public health facilities in Uganda and cross-sectional surveys conducted in target areas around these facilities in April 2021. Associations between gender and the incidence of malaria and non-malarial visits captured at the health facilities from patients residing within the target areas were estimated using poisson regression models controlling for seasonality. Associations between gender and data on health-seeking behaviour from the cross-sectional surveys were estimated using poisson regression models controlling for seasonality. RESULTS Overall, incidence of malaria diagnosed per 1000 person years was 735 among females and 449 among males (IRR = 1.72, 95% CI 1.68-1.77, p < 0.001), with larger differences among those 15-39 years (IRR = 2.46, 95% CI 2.34-2.58, p < 0.001) and over 39 years (IRR = 2.26, 95% CI 2.05-2.50, p < 0.001) compared to those under 15 years (IRR = 1.46, 95% CI 1.41-1.50, p < 0.001). Female gender was also associated with a higher incidence of visits where malaria was not suspected (IRR = 1.77, 95% CI 1.71-1.83, p < 0.001), with a similar pattern across age strata. These associations were consistent across the 12 individual health centres. From the cross-sectional surveys, females were more likely than males to report fever in the past 2 weeks and seek care at the local health centre (7.5% vs. 4.7%, p = 0.001) with these associations significant for those 15-39 years (RR = 2.49, 95% CI 1.17-5.31, p = 0.018) and over 39 years (RR = 2.56, 95% CI 1.00-6.54, p = 0.049). CONCLUSIONS Females disproportionately contribute to the burden of malaria diagnosed at public health facilities in Uganda, especially once they reach childbearing age. Contributing factors included more frequent visits to these facilities independent of malaria and a higher reported risk of seeking care at these facilities for febrile illnesses.
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Affiliation(s)
- Jaffer Okiring
- Clinical Epidemiology Unit, School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda. .,Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda.
| | - Adrienne Epstein
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, USA
| | - Jane F Namuganga
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Emmanuel V Kamya
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Isaiah Nabende
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Martha Nassali
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Asadu Sserwanga
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Samuel Gonahasa
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Mercy Muwema
- Clinical Epidemiology Unit, School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Steven M Kiwuwa
- Department of Child Health and Development Centre, School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Sarah G Staedke
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Moses R Kamya
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda.,School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Joaniter I Nankabirwa
- Clinical Epidemiology Unit, School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda.,Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, Kampala, Uganda
| | - Jessica Briggs
- Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Prasanna Jagannathan
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Stanford, USA
| | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, USA
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