1
|
Nguetsa GC, Elanga-Ndille E, Essangui Same EG, Nganso Keptchouang T, Mandeng SE, Ekoko Eyisap W, Binyang JA, Fogang B, Nouage L, Piameu M, Ayong L, Etang J, Wanji S, Eboumbou Moukoko CE. Utility of plasma anti-gSG6-P1 IgG levels in determining changes in Anopheles gambiae bite rates in a rural area of Cameroon. Sci Rep 2024; 14:14294. [PMID: 38906949 PMCID: PMC11192751 DOI: 10.1038/s41598-024-58337-8] [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: 11/16/2023] [Accepted: 03/27/2024] [Indexed: 06/23/2024] Open
Abstract
The applicability of the specific human IgG antibody response to Anopheles gambiae salivary Gland Protein-6 peptide 1 (gSG6-P1 salivary peptide) as a biomarker able to distinguish the level of exposure to mosquito bites according to seasonal variations has not yet been evaluated in Central African regions. The study aimed to provide the first reliable data on the IgG anti-gSG6-P1 response in rural area in Cameroon according to the dry- and rainy-season. Between May and December 2020, dry blood samples were collected from people living in the Bankeng village in the forest area of the Centre region of Cameroon. Malaria infection was determined by thick-blood smear microscopy and multiplex PCR. The level of IgG anti-gSG6-P1 response, was assessed by enzyme-linked immunosorbent assay. Anopheles density and aggressiveness were assessed using human landing catches. The prevalence of malaria infection remains significantly higher in the rainy season than in the dry season (77.57% vs 61.44%; p = 0.0001). The specific anti-gSG6-P1 IgG response could be detected in individuals exposed to few mosquito bites and showed inter-individual heterogeneity even when living in the same exposure area. In both seasons, the level of anti-gSG6-P1 IgG response was not significantly different between Plasmodium infected and non-infected individuals. Mosquito bites were more aggressive in the rainy season compared to the dry season (human biting rate-HBR of 15.05 b/p/n vs 1.5 b/p/n) where mosquito density was very low. Infected mosquitoes were found only during the rainy season (sporozoite rate = 10.63% and entomological inoculation rate-EIR = 1.42 ib/p/n). The level of IgG anti-gSG6-P1 response was significantly higher in the rainy season and correlated with HBR (p ˂ 0.0001). This study highlights the high heterogeneity of individual's exposure to the Anopheles gambiae s.l vector bites depending on the transmission season in the same area. These findings reinforce the usefulness of the anti-gSG6-P1 IgG response as an accurate immunological biomarker for detecting individual exposure to Anopheles gambiae s.l. bites during the low risk period of malaria transmission in rural areas and for the differentiating the level of exposure to mosquitoes.
Collapse
Affiliation(s)
- Glwadys Cheteug Nguetsa
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
- Department of Microbiology and Parasitology, Faculty of Sciences, The University of Buea, P.O. Box 63, Buea, Cameroon.
| | - Emmanuel Elanga-Ndille
- Department of Animal Biology, Faculty of Sciences, The University of Dschang, P.O. Box 96, Dschang, Cameroon
- Department of Medical Entomology, Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé, Cameroon
| | - Estelle Géraldine Essangui Same
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon
| | - Tatiana Nganso Keptchouang
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon
| | - Stanilas Elysée Mandeng
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Wolfgang Ekoko Eyisap
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Jérome Achille Binyang
- Department of Medical Entomology, Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
| | - Balotin Fogang
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
| | - Lynda Nouage
- Department of Medical Entomology, Centre for Research in Infectious Diseases, P.O. Box 13591, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, The University of Yaoundé, P.O. Box 337, Yaounde 1, Cameroon
| | - Micheal Piameu
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- Ecole des Sciences de La Santé, Université Catholique d'Afrique Centrale, P.O. Box 1110, Yaoundé, Cameroon
| | - Lawrence Ayong
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon
| | - Josiane Etang
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Faculty of Sciences, The University of Buea, P.O. Box 63, Buea, Cameroon
| | - Carole Else Eboumbou Moukoko
- Malaria Research Unit, Centre Pasteur Cameroon, P.O. Box 1274, Yaoundé, Cameroon.
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon.
- Laboratory of Parasitology, Mycology and Virology, Postgraduate Training Unit for Health Sciences, Postgraduate School for Pure and Applied Sciences, The University of Douala, P.O. Box 2701, Douala, Cameroon.
| |
Collapse
|
2
|
Kearney EA, Amratia P, Kang SY, Agius PA, Alene KA, O’Flaherty K, Oo WH, Cutts JC, Htike W, Da Silva Goncalves D, Razook Z, Barry AE, Drew D, Thi A, Aung KZ, Thu HK, Thein MM, Zaw NN, Htay WYM, Soe AP, Beeson JG, Simpson JA, Gething PW, Cameron E, Fowkes FJI. Geospatial joint modeling of vector and parasite serology to microstratify malaria transmission. Proc Natl Acad Sci U S A 2024; 121:e2320898121. [PMID: 38833464 PMCID: PMC11181033 DOI: 10.1073/pnas.2320898121] [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: 11/28/2023] [Accepted: 04/30/2024] [Indexed: 06/06/2024] Open
Abstract
The World Health Organization identifies a strong surveillance system for malaria and its mosquito vector as an essential pillar of the malaria elimination agenda. Anopheles salivary antibodies are emerging biomarkers of exposure to mosquito bites that potentially overcome sensitivity and logistical constraints of traditional entomological surveys. Using samples collected by a village health volunteer network in 104 villages in Southeast Myanmar during routine surveillance, the present study employs a Bayesian geostatistical modeling framework, incorporating climatic and environmental variables together with Anopheles salivary antigen serology, to generate spatially continuous predictive maps of Anopheles biting exposure. Our maps quantify fine-scale spatial and temporal heterogeneity in Anopheles salivary antibody seroprevalence (ranging from 9 to 99%) that serves as a proxy of exposure to Anopheles bites and advances current static maps of only Anopheles occurrence. We also developed an innovative framework to perform surveillance of malaria transmission. By incorporating antibodies against the vector and the transmissible form of malaria (sporozoite) in a joint Bayesian geostatistical model, we predict several foci of ongoing transmission. In our study, we demonstrate that antibodies specific for Anopheles salivary and sporozoite antigens are a logistically feasible metric with which to quantify and characterize heterogeneity in exposure to vector bites and malaria transmission. These approaches could readily be scaled up into existing village health volunteer surveillance networks to identify foci of residual malaria transmission, which could be targeted with supplementary interventions to accelerate progress toward elimination.
Collapse
Affiliation(s)
- Ellen A. Kearney
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC3010, Australia
| | - Punam Amratia
- Malaria Atlas Project, Telethon Kids Institute, Perth, WA6009, Australia
| | - Su Yun Kang
- Malaria Atlas Project, Telethon Kids Institute, Perth, WA6009, Australia
| | - Paul A. Agius
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC3010, Australia
- Biostatistics Unit, Faculty of Health, Deakin University, Melbourne, VIC3125, Australia
| | - Kefyalew Addis Alene
- Malaria Atlas Project, Telethon Kids Institute, Perth, WA6009, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA6102, Australia
| | | | - Win Han Oo
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Julia C. Cutts
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Department of Medicine at the Doherty Institute, The University of Melbourne, Melbourne, VIC3000, Australia
| | - Win Htike
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | | | - Zahra Razook
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Institute for Physical and Mental Health and Clinical Translation, School of Medicine, Deakin University, Geelong, VIC3216, Australia
| | - Alyssa E. Barry
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Institute for Physical and Mental Health and Clinical Translation, School of Medicine, Deakin University, Geelong, VIC3216, Australia
| | - Damien Drew
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
| | - Aung Thi
- Department of Public Health, Myanmar Ministry of Health and Sports, Nay Pyi Taw15011, Myanmar
| | - Kyaw Zayar Aung
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Htin Kyaw Thu
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Myat Mon Thein
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Nyi Nyi Zaw
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Wai Yan Min Htay
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - Aung Paing Soe
- Health Security and Malaria Program, Burnet Institute Myanmar, Yangon11201, Myanmar
| | - James G. Beeson
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Department of Infectious Diseases, The University of Melbourne, Melbourne, VIC3000, Australia
- Department of Microbiology, Monash University, Melbourne, VIC3800, Australia
- Central Clinical School, Monash University, Melbourne, VIC3004, Australia
| | - Julie A. Simpson
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC3010, Australia
| | - Peter W. Gething
- Malaria Atlas Project, Telethon Kids Institute, Perth, WA6009, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA6102, Australia
| | - Ewan Cameron
- Malaria Atlas Project, Telethon Kids Institute, Perth, WA6009, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA6102, Australia
| | - Freya J. I. Fowkes
- Disease Elimination Program, Burnet Institute, Melbourne, VIC3004, Australia
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC3010, Australia
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC3004, Australia
| |
Collapse
|
3
|
Mushtaq I, Sarwar MS, Chaudhry A, Shah SAH, Ahmad MM. Updates on traditional methods for combating malaria and emerging Wolbachia-based interventions. Front Cell Infect Microbiol 2024; 14:1330475. [PMID: 38716193 PMCID: PMC11074371 DOI: 10.3389/fcimb.2024.1330475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 03/14/2024] [Indexed: 05/24/2024] Open
Abstract
The escalating challenge of malaria control necessitates innovative approaches that extend beyond traditional control strategies. This review explores the incorporation of traditional vector control techniques with emerging Wolbachia-based interventions. Wolbachia, a naturally occurring bacteria, offers a novel approach for combatting vector-borne diseases, including malaria, by reducing the mosquitoes' ability to transmit these diseases. The study explores the rationale for this integration, presenting various case studies and pilot projects that have exhibited significant success. Employing a multi-dimensional approach that includes community mobilization, environmental modifications, and new biological methods, the paper posits that integrated efforts could mark a turning point in the struggle against malaria. Our findings indicate that incorporating Wolbachia-based strategies into existing vector management programs not only is feasible but also heightens the efficacy of malaria control initiatives in different countries especially in Pakistan. The paper concludes that continued research and international collaboration are imperative for translating these promising methods from the laboratory to the field, thereby offering a more sustainable and effective malaria control strategy.
Collapse
|
4
|
Trape JF, Diagne N, Diene-Sarr F, Faye J, Dieye-Ba F, Bassène H, Badiane A, Bouganali C, Tall A, Ndiaye R, Doucouré S, Wotodjo AN, Vigan-Womas I, Guillotte-Blisnick M, Talla C, Niang M, Touré-Baldé A, Perraut R, Roussilhon C, Druilhe P, Rogier C, Mercereau-Puijalon O, Loucoubar C, Sokhna C. One hundred malaria attacks since birth. A longitudinal study of African children and young adults exposed to high malaria transmission. EClinicalMedicine 2024; 67:102379. [PMID: 38188691 PMCID: PMC10770423 DOI: 10.1016/j.eclinm.2023.102379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/30/2023] [Accepted: 11/30/2023] [Indexed: 01/09/2024] Open
Abstract
Background Despite significant progress in malaria control over the past twenty years, malaria remains a leading cause of child morbidity and mortality in Tropical Africa. As most patients do not consult any health facility much uncertainty persists about the true burden of the disease and the range of individual differences in susceptibility to malaria. Methods Over a 25-years period, from 1990 to 2015, the inhabitants of Dielmo village, Senegal, an area of intense malaria transmission, have been monitored daily for their presence in the village and the occurrence of diseases. In case of fever thick blood films were systematically examined through microscopy for malaria parasites and patients received prompt diagnosis and treatment. Findings We analysed data collected in 111 children and young adults monitored for at least 10 years (mean 17.3 years, maximum 25 years) enrolled either at birth (95 persons) or during the two first years of life. A total of 11,599 episodes of fever were documented, including 5268 malaria attacks. The maximum number of malaria attacks in a single person was 112. Three other persons suffered one hundred or more malaria attacks during follow-up. The minimum number of malaria attacks in a single person was 11. The mean numbers of malaria attacks in children reaching their 4th, 7th, and 10th birthdays were 23.0, 37.7, and 43.6 attacks since birth, respectively. Sixteen children (14.4%) suffered ten or more malaria attacks each year at ages 1-3 years, and six children (5.4%) each year at age 4-6 years. Interpretation Long-term close monitoring shows that in highly endemic areas the malaria burden is higher than expected. Susceptibility to the disease may vary up to 10-fold, and for most children childhood is an endless history of malaria fever episodes. No other parasitic, bacterial or viral infection in human populations has such an impact on health. Funding The Pasteur Institutes of Dakar and Paris, the Institut de Recherche pour le Développement, and the French Ministry of Cooperation provided funding.
Collapse
Affiliation(s)
| | - Nafissatou Diagne
- Institut de Recherche pour le Développement, VITROME, Dakar, Senegal
| | | | - Joseph Faye
- Institut Pasteur de Dakar, Epidemiology Unit, Dakar, Senegal
| | - Fambaye Dieye-Ba
- Institut de Recherche pour le Développement, VITROME, Dakar, Senegal
| | - Hubert Bassène
- Institut de Recherche pour le Développement, VITROME, Dakar, Senegal
| | | | - Charles Bouganali
- Institut de Recherche pour le Développement, VITROME, Dakar, Senegal
| | - Adama Tall
- Institut Pasteur de Dakar, Epidemiology Unit, Dakar, Senegal
| | | | | | | | - Inès Vigan-Womas
- Institut Pasteur de Dakar, Immunology Unit, Dakar, Senegal
- Institut Pasteur, Department of Parasitology and Insect Vectors, Paris, France
| | | | - Cheikh Talla
- Institut Pasteur de Dakar, Epidemiology Unit, Dakar, Senegal
| | - Makhtar Niang
- Institut Pasteur de Dakar, Immunology Unit, Dakar, Senegal
| | | | - Ronald Perraut
- Institut Pasteur de Dakar, Immunology Unit, Dakar, Senegal
- Institut Pasteur, Department of Parasitology and Insect Vectors, Paris, France
| | - Christian Roussilhon
- Institut Pasteur de Dakar, Immunology Unit, Dakar, Senegal
- Institut Pasteur, Bio-medical Parasitology, Paris, France
| | - Pierre Druilhe
- Institut Pasteur, Bio-medical Parasitology, Paris, France
| | - Christophe Rogier
- Institut Pasteur de Dakar, Epidemiology Unit, Dakar, Senegal
- Primum Vitare, Paris, France
| | | | | | - Cheikh Sokhna
- Institut de Recherche pour le Développement, VITROME, Dakar, Senegal
| |
Collapse
|
5
|
de Graeff N, Jongsma KR, Bredenoord AL. Alleviating the burden of malaria with gene drive technologies? A biocentric analysis of the moral permissibility of modifying malaria mosquitoes. JOURNAL OF MEDICAL ETHICS 2023; 49:765-771. [PMID: 36854625 DOI: 10.1136/jme-2022-108359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 02/04/2023] [Indexed: 06/18/2023]
Abstract
Gene drive technologies (GDTs) have been proposed as a potential new way to alleviate the burden of malaria, yet have also raised ethical questions. A central ethical question regarding GDTs relates to whether it is morally permissible to intentionally modify or eradicate mosquitoes in this way and how the inherent worth of humans and non-human organisms should be factored into determining this. Existing analyses of this matter have thus far generally relied on anthropocentric and zoocentric perspectives and rejected an individualist biocentric outlook in which all living organisms are taken to matter morally for their own sake. In this paper, we reconsider the implications of taking a biocentric approach and highlight nuances that may not be evident at first glance. First, we shortly discuss biocentric perspectives in general, and then outline Paul Taylor's biocentric theory of respect for nature. Second, we explore how conflicting claims towards different organisms should be prioritised from this perspective and subsequently apply this to the context of malaria control using GDTs. Our ethical analysis shows that this context invokes the principle of self-defence, which could override the pro tanto concerns that a biocentrist would have against modifying malaria mosquitoes in this way if certain conditions are met. At the same time, the case study of GDTs underlines the relevance of previously posed questions and criticism regarding the internal consistency of Taylor's egalitarian biocentrism.
Collapse
Affiliation(s)
- Nienke de Graeff
- Department of Bioethics & Health Humanities, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Ethics & Law, Leiden University Medical Center, Leiden, The Netherlands
| | - Karin Rolanda Jongsma
- Department of Bioethics & Health Humanities, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Annelien L Bredenoord
- Department of Bioethics & Health Humanities, University Medical Center Utrecht, Utrecht, The Netherlands
- Erasmus School of Philosophy, Erasmus University Rotterdam, Rotterdam, The Netherlands
| |
Collapse
|
6
|
Woyessa D, Morou E, Wipf N, Dada N, Mavridis K, Vontas J, Yewhalaw D. Species composition, infection rate and detection of resistant alleles in Anopheles funestus (Diptera: Culicidae) from Lare, a malaria hotspot district of Ethiopia. Malar J 2023; 22:233. [PMID: 37573300 PMCID: PMC10422748 DOI: 10.1186/s12936-023-04667-3] [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: 12/22/2022] [Accepted: 08/07/2023] [Indexed: 08/14/2023] Open
Abstract
BACKGROUND Anopheles funestus, which is considered as secondary vector of malaria in Ethiopia, is known to have several morphologically indistinguishable (sibling) species. Accurate identification of sibling species is crucial to understand their biology, behaviour and vector competence. In this study, molecular identification was conducted on the Ethiopian An. funestus populations. Moreover, insecticide resistance mechanism markers were detected, including ace N485I, kdr L1014F, L1014S, and CYP6P9a TaqMan qPCR was used to detect the infective stage of the parasite from field collected adult female An. funestus populations. METHODS Adult female mosquito collection was conducted from Lare, Gambella Regional State of Ethiopia between June 2018 to July 2020 using CDC light traps and HLC. Sub-samples of the morphologically identified An. funestus mosquitoes were molecularly identified using species-specific PCR, and the possible presence of insecticide resistance alleles was investigated using TaqMan qPCR (N485I-Ace-1), PCR-Sanger sequencing (L1014F-kdr), and PCR-RFLP (CYP6P9a resistance allele). Following head/thorax dissection, the TaqMan qPCR assay was used to investigate the presence of the infective stage Plasmodium parasite species. RESULTS A total of 1086 adult female An. funestus mosquitoes were collected during the study period. All sub-samples (N = 20) that were morphologically identified as An. funestus sensu lato (s.l.) were identified as An. funestus sensu stricto (s.s.) using species- specific PCR assay. The PCR-RFLP assay that detects the CYP6P9a resistance allele that confers pyrethroid resistance in An. funestus was applied in N = 30 randomly selected An. funestus s.l. SPECIMENS None of the specimens showed a digestion pattern consistent with the presence of the CYP6P9a resistance allele in contrast to what was observed in the positive control. Consequently, all samples were characterized as wild type. The qPCR TaqMan assay that detects the N485I acetylcholinesterase-1 mutation conferring resistance to organophosphates/carbamates in An. funestus was used in (N = 144) samples. All samples were characterized as wild type. The kdr L1014F and L1014S mutations in the VGSC gene that confer resistance to pyrethroids and DDT were analysed with direct Sanger sequencing after PCR and clean-up of the PCR products were also characterized as wild type. None of the samples (N = 169) were found positive for Plasmodium (P. falciparum/ovale/malariae/vivax) detection. CONCLUSION All An. funestus s.l. samples from Lare were molecularly identified as An. funestus s.s. No CYP6P9, N485I acetylcholinesterase 1, kdr L1014F or L1014S mutations were detected in the An. funestus samples. None of the An. funestus samples were positive for Plasmodium. Although the current study did not detect any insecticide resistant mechanism, it provides a reference for future vector monitoring programmes. Regular monitoring of resistance mechanisms covering wider geographical areas of Ethiopia where this vector is distributed is important for improving the efficacy of vector control programs.
Collapse
Affiliation(s)
- Delelegn Woyessa
- Department of Biology, College of Natural Sciences, Jimma University, P. O. Box 378, Jimma, Ethiopia.
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.
- Tropical and Infectious Diseases Research Centre (TIDRC), P.O. Box 378, Jimma, Ethiopia.
| | - Evangelia Morou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - Nadja Wipf
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Nsa Dada
- School of Life Sciences, College of Liberal Arts and Sciences, Arizona State University, Tempe, USA
| | - Konstantinos Mavridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013, Heraklion, Greece
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Centre (TIDRC), P.O. Box 378, Jimma, Ethiopia
| |
Collapse
|
7
|
Mzilahowa T, Gowelo S, Chiphwanya J, Bauleni A, Mukaka M. Anopheles funestus sensu stricto Giles (Diptera:Culicidae) bites after sunrise at two rural villages in northern Malawi and its implications for malaria vector control. Malawi Med J 2023; 35:80-88. [PMID: 38264168 PMCID: PMC10731528 DOI: 10.4314/mmj.v35i2.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024] Open
Abstract
Introduction Malawi has scaled up distribution and use of LLINs but their effectiveness depends on vector behaviour. This study reports information on where and when peak biting takes place by Anopheles vectors at two study sites in northern Malawi. Methods The study was carried out at a single village each in Nkhata Bay and Karonga districts, northern Malawi. Monthly, three teams of four people each sampled mosquitoes using Human Landing Collections (HLCs) from 6.00 pm to 6.00 am. Mosquitoes were counted and identified by PCR. Plasmodium falciparum sporozoites were detected by ELISA and an entomological inoculation rate was estimated. Results A total of 4,668 and 2,079 mosquitoes were sampled in Nkhata Bay and Karonga districts respectively. An. funestus s.s was common (91.3%; n = 2,611) in Nkhata Bay while An. arabiensis was common (96.9%; n = 706) in Karonga. Pf sporozoite rates varied from 0.8% (4/484) to 3.3% (51/1558). Individuals in Nkhata Bay received more bites (approx. 200 bites/ person/ night) compared to Karonga (approx. 50 bites/ person/ night). An. funestus was more likely to bite indoors (p=0.002) while An. arabiensis was (p=0.05) more likely to bite outdoors. Furthermore, An. funestus peak biting was in the early morning hours from 4:00 am (approx. 331 and 177 bites/ person/ night indoors and outdoors respectively) and remained high till 6:00 am. An. arabiensis peak biting (approx. 63 and 62 bites/ person/ night indoors and outdoors respectively) was around mid-night (12:00). An EIR of 108.4 infective bites/ person/ year was estimated for Nkhata Bay compared to 9.1 infective bites/ person/ year for Karonga. Conclusion An. funestus s.s. had a considerable Pf sporozite infection rate and EIR. The shift in biting behaviour shown by this species poses a challenge to malaria control. Further studies are required to understand the biting behaviour of Anopheles vectors in Malawi.
Collapse
Affiliation(s)
- Themba Mzilahowa
- MAC Communicable Diseases Action Centre, Kamuzu University of Health Sciences, Malawi
| | - Steven Gowelo
- MAC Communicable Diseases Action Centre, Kamuzu University of Health Sciences, Malawi
| | | | - Andrew Bauleni
- MAC Communicable Diseases Action Centre, Kamuzu University of Health Sciences, Malawi
| | - Mavuto Mukaka
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, UK
| |
Collapse
|
8
|
García GA, Janko M, Hergott DEB, Donfack OT, Smith JM, Mba Eyono JN, DeBoer KR, Nguema Avue RM, Phiri WP, Aldrich EM, Schwabe C, Stabler TC, Rivas MR, Cameron E, Guerra CA, Cook J, Kleinschmidt I, Bradley J. Identifying individual, household and environmental risk factors for malaria infection on Bioko Island to inform interventions. Malar J 2023; 22:72. [PMID: 36859263 PMCID: PMC9979414 DOI: 10.1186/s12936-023-04504-7] [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: 08/08/2022] [Accepted: 02/18/2023] [Indexed: 03/03/2023] Open
Abstract
BACKGROUND Since 2004, malaria transmission on Bioko Island has declined significantly as a result of the scaling-up of control interventions. The aim of eliminating malaria from the Island remains elusive, however, underscoring the need to adapt control to the local context. Understanding the factors driving the risk of malaria infection is critical to inform optimal suits of interventions in this adaptive approach. METHODS This study used individual and household-level data from the 2015 and 2018 annual malaria indicator surveys on Bioko Island, as well as remotely-sensed environmental data in multilevel logistic regression models to quantify the odds of malaria infection. The analyses were stratified by urban and rural settings and by survey year. RESULTS Malaria prevalence was higher in 10-14-year-old children and similar between female and male individuals. After adjusting for demographic factors and other covariates, many of the variables investigated showed no significant association with malaria infection. The factor most strongly associated was history of travel to mainland Equatorial Guinea (mEG), which increased the odds significantly both in urban and rural settings (people who travelled had 4 times the odds of infection). Sleeping under a long-lasting insecticidal net decreased significantly the odds of malaria across urban and rural settings and survey years (net users had around 30% less odds of infection), highlighting their contribution to malaria control on the Island. Improved housing conditions indicated some protection, though this was not consistent across settings and survey year. CONCLUSIONS Malaria risk on Bioko Island is heterogeneous and determined by a combination of factors interacting with local mosquito ecology. These interactions grant further investigation in order to better adapt control according to need. The single most important risk factor identified was travel to mEG, in line with previous investigations, and represents a great challenge for the success of malaria control on the Island.
Collapse
Affiliation(s)
| | - Mark Janko
- Duke Global Health Institute, Duke University, Durham, NC, USA
| | - Dianna E B Hergott
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA
| | | | | | | | | | | | - Wonder P Phiri
- MCD Global Health, Bioko Island, Malabo, Equatorial Guinea
| | | | | | - Thomas C Stabler
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Matilde Riloha Rivas
- Equatorial Guinea Ministry of Health and Social Welfare, Bioko Island, Malabo, Equatorial Guinea
| | - Ewan Cameron
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
| | | | - Jackie Cook
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Immo Kleinschmidt
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
- School of Pathology, Faculty of Health Science, Wits Institute for Malaria Research, University of Witwatersrand, Johannesburg, South Africa
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| |
Collapse
|
9
|
IgG antibody responses to Anopheles gambiae gSG6-P1 salivary peptide are induced in human populations exposed to secondary malaria vectors in forest areas in Cameroon. PLoS One 2022; 17:e0276991. [PMID: 36355922 PMCID: PMC9648791 DOI: 10.1371/journal.pone.0276991] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 10/18/2022] [Indexed: 11/12/2022] Open
Abstract
Human IgG antibody response to Anopheles gambiae gSG6-P1 salivary peptide was reported to be a pertinent indicator for assessing human exposure to mosquito bites and evaluating the risk of malaria transmission as well as the effectiveness of vector control strategies. However, the applicability of this marker to measure malaria transmission risk where human populations are mostly bitten by secondary vectors in Africa has not yet been evaluated. In this study, we aimed to investigate whether anti-gSG6-P1 antibodies response could be induced in humans living in forest areas in Cameroon where An. gambiae s.l is not predominant. In October 2019 at the pick of the rainy season, blood samples were collected from people living in the Nyabessang in the forest area in the South region of Cameroon. Malaria infection was determined using thick blood smear microscopy and Rapid Diagnostic Test. The level of IgG Anti-gSG6-P1 response as a biomarker of human exposure to Anopheles bite, was assessed using enzyme-linked immunosorbent assay. Mosquitoes were collected using the human landing catches to assess Anopheles density and for the identification of Anopheles species present in that area. IgG antibody response to the gSG6-P1 salivary peptide was detected in inhabitants of Nyabessang with high inter-individual heterogeneity. No significant variation in the level of this immune response was observed according to age and gender. The concentration of gSG6-P1 antibodies was significantly correlated with the malaria infection status and, Plasmodium falciparum-infected individuals presented a significantly higher level of IgG response than uninfected individuals (p = 0.0087). No significant difference was observed according to the use of insecticide treated nets. Out of the 1,442 Anopheles mosquitoes species collected, 849 (58.9%) were identified as An. paludis, 489 (33.91%) as An. moucheti, 28 (4.44%) as An. nili, 22 (2.08%) as An. gambiae s.l and 10 (0.69%) as An. marshallii. Our findings show that IgG response to An. gambiae gSG6-P1 peptide could be detected in humans exposed predominantly to An. moucheti and An. paludis bites. Taken together, the data revealed the potential of the Anti-gSG6-P1 IgG antibody response to serve as a universal marker to assess human exposure to any Anopheles species.
Collapse
|
10
|
Wong W, Volkman S, Daniels R, Schaffner S, Sy M, Ndiaye YD, Badiane AS, Deme AB, Diallo MA, Gomis J, Sy N, Ndiaye D, Wirth DF, Hartl DL. R H: a genetic metric for measuring intrahost Plasmodium falciparum relatedness and distinguishing cotransmission from superinfection. PNAS NEXUS 2022; 1:pgac187. [PMID: 36246152 PMCID: PMC9552330 DOI: 10.1093/pnasnexus/pgac187] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 09/08/2022] [Indexed: 01/29/2023]
Abstract
Multiple-strain (polygenomic) infections are a ubiquitous feature of Plasmodium falciparum parasite population genetics. Under simple assumptions of superinfection, polygenomic infections are hypothesized to be the result of multiple infectious bites. As a result, polygenomic infections have been used as evidence of repeat exposure and used to derive genetic metrics associated with high transmission intensity. However, not all polygenomic infections are the result of multiple infectious bites. Some result from the transmission of multiple, genetically related strains during a single infectious bite (cotransmission). Superinfection and cotransmission represent two distinct transmission processes, and distinguishing between the two could improve inferences regarding parasite transmission intensity. Here, we describe a new metric, R H, that utilizes the correlation in allelic state (heterozygosity) within polygenomic infections to estimate the likelihood that the observed complexity resulted from either superinfection or cotransmission. R H is flexible and can be applied to any type of genetic data. As a proof of concept, we used R H to quantify polygenomic relatedness and estimate cotransmission and superinfection rates from a set of 1,758 malaria infections genotyped with a 24 single nucleotide polymorphism (SNP) molecular barcode. Contrary to expectation, we found that cotransmission was responsible for a significant fraction of 43% to 53% of the polygenomic infections collected in three distinct epidemiological regions in Senegal. The prediction that polygenomic infections frequently result from cotransmission stresses the need to incorporate estimates of relatedness within polygenomic infections to ensure the accuracy of genomic epidemiology surveillance data for informing public health activities.
Collapse
Affiliation(s)
- Wesley Wong
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Sarah Volkman
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
- College of Natural, Behavioral, and Health Sciences, Simmons University, Boston, MA 02115, USA
| | - Rachel Daniels
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Stephen Schaffner
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Mouhamad Sy
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Yaye Die Ndiaye
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Aida S Badiane
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Awa B Deme
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Mamadou Alpha Diallo
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Jules Gomis
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Ngayo Sy
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Daouda Ndiaye
- Laboratory of Parasitology and Mycology, Aristide le Dantec Hospital, Cheikh Anta Diop University, Dakar 10200, Senegal
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
- Infectious Disease and Microbiome Program, Broad Institute, Cambridge, MA 02142, USA
| | - Daniel L Hartl
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| |
Collapse
|
11
|
Masserey T, Lee T, Golumbeanu M, Shattock AJ, Kelly SL, Hastings IM, Penny MA. The influence of biological, epidemiological, and treatment factors on the establishment and spread of drug-resistant Plasmodium falciparum. eLife 2022; 11:e77634. [PMID: 35796430 PMCID: PMC9262398 DOI: 10.7554/elife.77634] [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: 02/05/2022] [Accepted: 06/22/2022] [Indexed: 11/13/2022] Open
Abstract
The effectiveness of artemisinin-based combination therapies (ACTs) to treat Plasmodium falciparum malaria is threatened by resistance. The complex interplay between sources of selective pressure-treatment properties, biological factors, transmission intensity, and access to treatment-obscures understanding how, when, and why resistance establishes and spreads across different locations. We developed a disease modelling approach with emulator-based global sensitivity analysis to systematically quantify which of these factors drive establishment and spread of drug resistance. Drug resistance was more likely to evolve in low transmission settings due to the lower levels of (i) immunity and (ii) within-host competition between genotypes. Spread of parasites resistant to artemisinin partner drugs depended on the period of low drug concentration (known as the selection window). Spread of partial artemisinin resistance was slowed with prolonged parasite exposure to artemisinin derivatives and accelerated when the parasite was also resistant to the partner drug. Thus, to slow the spread of partial artemisinin resistance, molecular surveillance should be supported to detect resistance to partner drugs and to change ACTs accordingly. Furthermore, implementing more sustainable artemisinin-based therapies will require extending parasite exposure to artemisinin derivatives, and mitigating the selection windows of partner drugs, which could be achieved by including an additional long-acting drug.
Collapse
Affiliation(s)
- Thiery Masserey
- Swiss Tropical and Public Health InstituteAllschwilSwitzerland
- University of BaselBaselSwitzerland
| | - Tamsin Lee
- Swiss Tropical and Public Health InstituteAllschwilSwitzerland
- University of BaselBaselSwitzerland
| | - Monica Golumbeanu
- Swiss Tropical and Public Health InstituteAllschwilSwitzerland
- University of BaselBaselSwitzerland
| | - Andrew J Shattock
- Swiss Tropical and Public Health InstituteAllschwilSwitzerland
- University of BaselBaselSwitzerland
| | - Sherrie L Kelly
- Swiss Tropical and Public Health InstituteAllschwilSwitzerland
- University of BaselBaselSwitzerland
| | - Ian M Hastings
- Liverpool School of Tropical MedicineLiverpoolUnited Kingdom
| | - Melissa A Penny
- Swiss Tropical and Public Health InstituteAllschwilSwitzerland
- University of BaselBaselSwitzerland
| |
Collapse
|
12
|
Ukawuba I, Shaman J. Inference and dynamic simulation of malaria using a simple climate-driven entomological model of malaria transmission. PLoS Comput Biol 2022; 18:e1010161. [PMID: 35679241 PMCID: PMC9182318 DOI: 10.1371/journal.pcbi.1010161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 05/02/2022] [Indexed: 12/02/2022] Open
Abstract
Given the crucial role of climate in malaria transmission, many mechanistic models of malaria represent vector biology and the parasite lifecycle as functions of climate variables in order to accurately capture malaria transmission dynamics. Lower dimension mechanistic models that utilize implicit vector dynamics have relied on indirect climate modulation of transmission processes, which compromises investigation of the ecological role played by climate in malaria transmission. In this study, we develop an implicit process-based malaria model with direct climate-mediated modulation of transmission pressure borne through the Entomological Inoculation Rate (EIR). The EIR, a measure of the number of infectious bites per person per unit time, includes the effects of vector dynamics, resulting from mosquito development, survivorship, feeding activity and parasite development, all of which are moderated by climate. We combine this EIR-model framework, which is driven by rainfall and temperature, with Bayesian inference methods, and evaluate the model’s ability to simulate local transmission across 42 regions in Rwanda over four years. Our findings indicate that the biologically-motivated, EIR-model framework is capable of accurately simulating seasonal malaria dynamics and capturing of some of the inter-annual variation in malaria incidence. However, the model unsurprisingly failed to reproduce large declines in malaria transmission during 2018 and 2019 due to elevated anti-malaria measures, which were not accounted for in the model structure. The climate-driven transmission model also captured regional variation in malaria incidence across Rwanda’s diverse climate, while identifying key entomological and epidemiological parameters important to seasonal malaria dynamics. In general, this new model construct advances the capabilities of implicitly-forced lower dimension dynamical malaria models by leveraging climate drivers of malaria ecology and transmission. Climate plays a fundamental and complex role in malaria transmission, by acting on multiple aspects of mosquito ecology and parasite transmissibility. However, to express malaria transmission pressure, malaria models with implicit vector dynamics have relied on indirect predictors of vector ecology, such as temporal seasonality or interpolations of rainfall/temperature, instead of entomological processes directly informed by ambient conditions. This approach obscures the specific influence of environmental conditions on relevant vector and parasite ecology, as well as meaningful interpretation of climate variability within these models. Here, we demonstrate that both interpretability and ecological effect from climate can be instantiated in lower dimension dynamical models through representation of transmission pressures via a climate-driven Entomological Inoculation Rate (EIR). This process-based model framework is driven by local rainfall and temperature, which regulate multiple aspects of the EIR, namely mosquito density, host-seeking activity, and parasite infectivity. Our results indicate that the climate-driven model construct is able to reproduce regional and local malaria transmission at seasonal and inter-annual time scales, while enabling identification of key entomological determinants of transmission.
Collapse
Affiliation(s)
- Israel Ukawuba
- Columbia University, Mailman School of Public Health, New York, New York, United States of America
- * E-mail:
| | - Jeffrey Shaman
- Columbia University, Mailman School of Public Health, New York, New York, United States of America
| |
Collapse
|
13
|
Akuamoah-Boateng Y, Brenyah RC, Kwarteng SA, Obuam P, Owusu-Frimpong I, Agyapong AK, Badu K. Malaria Transmission, Vector Diversity, and Insecticide Resistance at a Peri-Urban Site in the Forest Zone of Ghana. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.739771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
IntroductionRecent surge of Anopheles resistance to major classes of World Health Organization (WHO)-approved insecticides globally necessitates the need for information about local malaria vector populations. It is believed that insecticide efficacy loss may lead to operational failure of control interventions and an increase in malaria infection transmission. We investigated the susceptibility levels of malaria vectors to all classes of WHO-approved vector control insecticides and described the dynamics of malaria transmission in a peri-urban setting.MethodsFit 3–5-day-old adults that emerged from Anopheles larvae collected from several different sites in the study area were subjected to the WHO bioassay for detecting insecticide resistance. The knockdown resistance gene (kdr) mutations within the vector populations were detected using PCR. Entomological inoculation rates were determined using the human landing catch technique and Plasmodium falciparum circumsporozoite ELISA.ResultsThe malaria vectors from the study area were resistant to all classes of insecticides tested. Out of the 284 Anopheles complex specimen assayed for the resistance study, 265 (93.30%) were identified as Anopheles gambiae s.s. The kdr gene was detected in 90% of the Anopheles gambiae s.s. assayed. In an area where Anopheles coluzzii resistance to insecticides had never been reported, the kdr gene was detected in 78% of the Anopheles coluzzii sampled. The entomological inoculation rate (EIR) for the dry season was 1.44 ib/m/n, whereas the EIR for the rainy season was 2.69 ib/m/n.ConclusionsThis study provides information on the high parasite inoculation rate and insecticide resistance of malaria vectors in a peri-urban community, which is critical in the development of an insecticide resistance management program for the community.
Collapse
|
14
|
Jacob CG, Thuy-Nhien N, Mayxay M, Maude RJ, Quang HH, Hongvanthong B, Vanisaveth V, Ngo Duc T, Rekol H, van der Pluijm R, von Seidlein L, Fairhurst R, Nosten F, Hossain MA, Park N, Goodwin S, Ringwald P, Chindavongsa K, Newton P, Ashley E, Phalivong S, Maude R, Leang R, Huch C, Dong LT, Nguyen KT, Nhat TM, Hien TT, Nguyen H, Zdrojewski N, Canavati S, Sayeed AA, Uddin D, Buckee C, Fanello CI, Onyamboko M, Peto T, Tripura R, Amaratunga C, Myint Thu A, Delmas G, Landier J, Parker DM, Chau NH, Lek D, Suon S, Callery J, Jittamala P, Hanboonkunupakarn B, Pukrittayakamee S, Phyo AP, Smithuis F, Lin K, Thant M, Hlaing TM, Satpathi P, Satpathi S, Behera PK, Tripura A, Baidya S, Valecha N, Anvikar AR, Ul Islam A, Faiz A, Kunasol C, Drury E, Kekre M, Ali M, Love K, Rajatileka S, Jeffreys AE, Rowlands K, Hubbart CS, Dhorda M, Vongpromek R, Kotanan N, Wongnak P, Almagro Garcia J, Pearson RD, Ariani CV, Chookajorn T, Malangone C, Nguyen T, Stalker J, Jeffery B, Keatley J, Johnson KJ, Muddyman D, Chan XHS, Sillitoe J, Amato R, Simpson V, Gonçalves S, Rockett K, Day NP, Dondorp AM, Kwiatkowski DP, Miotto O. Genetic surveillance in the Greater Mekong subregion and South Asia to support malaria control and elimination. eLife 2021; 10:e62997. [PMID: 34372970 PMCID: PMC8354633 DOI: 10.7554/elife.62997] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 06/30/2021] [Indexed: 02/04/2023] Open
Abstract
Background National Malaria Control Programmes (NMCPs) currently make limited use of parasite genetic data. We have developed GenRe-Mekong, a platform for genetic surveillance of malaria in the Greater Mekong Subregion (GMS) that enables NMCPs to implement large-scale surveillance projects by integrating simple sample collection procedures in routine public health procedures. Methods Samples from symptomatic patients are processed by SpotMalaria, a high-throughput system that produces a comprehensive set of genotypes comprising several drug resistance markers, species markers and a genomic barcode. GenRe-Mekong delivers Genetic Report Cards, a compendium of genotypes and phenotype predictions used to map prevalence of resistance to multiple drugs. Results GenRe-Mekong has worked with NMCPs and research projects in eight countries, processing 9623 samples from clinical cases. Monitoring resistance markers has been valuable for tracking the rapid spread of parasites resistant to the dihydroartemisinin-piperaquine combination therapy. In Vietnam and Laos, GenRe-Mekong data have provided novel knowledge about the spread of these resistant strains into previously unaffected provinces, informing decision-making by NMCPs. Conclusions GenRe-Mekong provides detailed knowledge about drug resistance at a local level, and facilitates data sharing at a regional level, enabling cross-border resistance monitoring and providing the public health community with valuable insights. The project provides a rich open data resource to benefit the entire malaria community. Funding The GenRe-Mekong project is funded by the Bill and Melinda Gates Foundation (OPP11188166, OPP1204268). Genotyping and sequencing were funded by the Wellcome Trust (098051, 206194, 203141, 090770, 204911, 106698/B/14/Z) and Medical Research Council (G0600718). A proportion of samples were collected with the support of the UK Department for International Development (201900, M006212), and Intramural Research Program of the National Institute of Allergy and Infectious Diseases.
Collapse
Affiliation(s)
| | | | - Mayfong Mayxay
- Lao-Oxford-Mahosot Hospital-Wellcome Research Unit (LOMWRU), Microbiology Laboratory, Mahosot HospitalVientianeLao People's Democratic Republic
- Institute of Research and Education Development (IRED), University of Health Sciences, Ministry of HealthVientianeLao People's Democratic Republic
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
| | - Richard J Maude
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
- Harvard TH Chan School of Public Health, Harvard UniversityBostonUnited States
| | - Huynh Hong Quang
- Institute of Malariology, Parasitology and Entomology (IMPE-QN)Quy NhonViet Nam
| | - Bouasy Hongvanthong
- Centre of Malariology, Parasitology, and EntomologyVientianeLao People's Democratic Republic
| | - Viengxay Vanisaveth
- Centre of Malariology, Parasitology, and EntomologyVientianeLao People's Democratic Republic
| | - Thang Ngo Duc
- National Institute of Malariology, Parasitology and Entomology (NIMPE)HanoiViet Nam
| | - Huy Rekol
- National Center for Parasitology, Entomology, and Malaria ControlPhnom PenhCambodia
| | - Rob van der Pluijm
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | - Lorenz von Seidlein
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | - Rick Fairhurst
- National Institute of Allergy and Infectious Diseases, National Institutes of HealthRockvilleUnited States
| | - François Nosten
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Shoklo Malaria Research UnitMae SotThailand
| | | | - Naomi Park
- Wellcome Sanger InstituteHinxtonUnited Kingdom
| | | | | | | | - Paul Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Research Unit (LOMWRU), Microbiology Laboratory, Mahosot HospitalVientianeLao People's Democratic Republic
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | - Elizabeth Ashley
- Lao-Oxford-Mahosot Hospital-Wellcome Research Unit (LOMWRU), Microbiology Laboratory, Mahosot HospitalVientianeLao People's Democratic Republic
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
| | - Sonexay Phalivong
- Lao-Oxford-Mahosot Hospital-Wellcome Research Unit (LOMWRU), Microbiology Laboratory, Mahosot HospitalVientianeLao People's Democratic Republic
| | - Rapeephan Maude
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
- Faculty of Medicine, Ramathibodi Hospital, Mahidol UniversityBangkokThailand
| | - Rithea Leang
- National Center for Parasitology, Entomology, and Malaria ControlPhnom PenhCambodia
| | - Cheah Huch
- National Center for Parasitology, Entomology, and Malaria ControlPhnom PenhCambodia
| | - Le Thanh Dong
- Institute of Malariology, Parasitology and Entomology (IMPEHCM)Ho Chi Minh CityViet Nam
| | - Kim-Tuyen Nguyen
- Oxford University Clinical Research UnitHo Chi Minh CityViet Nam
| | - Tran Minh Nhat
- Oxford University Clinical Research UnitHo Chi Minh CityViet Nam
| | - Tran Tinh Hien
- Oxford University Clinical Research UnitHo Chi Minh CityViet Nam
| | | | | | | | | | - Didar Uddin
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | - Caroline Buckee
- Harvard TH Chan School of Public Health, Harvard UniversityBostonUnited States
| | - Caterina I Fanello
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | - Marie Onyamboko
- Kinshasa School of Public Health, University of KinshasaKinshasaDemocratic Republic of the Congo
| | - Thomas Peto
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | - Rupam Tripura
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | - Chanaki Amaratunga
- National Institute of Allergy and Infectious Diseases, National Institutes of HealthRockvilleUnited States
| | - Aung Myint Thu
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Shoklo Malaria Research UnitMae SotThailand
| | - Gilles Delmas
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Shoklo Malaria Research UnitMae SotThailand
| | - Jordi Landier
- Shoklo Malaria Research UnitMae SotThailand
- Aix-Marseille Université, INSERM, IRD, SESSTIM, Aix Marseille Institute of Public Health, ISSPAMMarseilleFrance
| | - Daniel M Parker
- Shoklo Malaria Research UnitMae SotThailand
- Susan and Henry Samueli College of Health Sciences, University of California, IrvineIrvineUnited States
| | | | - Dysoley Lek
- National Center for Parasitology, Entomology, and Malaria ControlPhnom PenhCambodia
| | - Seila Suon
- National Center for Parasitology, Entomology, and Malaria ControlPhnom PenhCambodia
| | - James Callery
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | | | | | - Sasithon Pukrittayakamee
- Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
- The Royal Society of ThailandBangkokThailand
| | - Aung Pyae Phyo
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Myanmar-Oxford Clinical Research UnitYangonMyanmar
| | - Frank Smithuis
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Myanmar-Oxford Clinical Research UnitYangonMyanmar
| | - Khin Lin
- Department of Medical ResearchPyin Oo LwinMyanmar
| | - Myo Thant
- Defence Services Medical Research CentreYangonMyanmar
| | | | | | | | | | | | | | - Neena Valecha
- National Institute of Malaria Research, Indian Council of Medical ResearchNew DelhiIndia
| | - Anupkumar R Anvikar
- National Institute of Malaria Research, Indian Council of Medical ResearchNew DelhiIndia
| | | | - Abul Faiz
- Malaria Research Group and Dev Care FoundationDhakaBangladesh
| | - Chanon Kunasol
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | | | - Mihir Kekre
- Wellcome Sanger InstituteHinxtonUnited Kingdom
| | - Mozam Ali
- Wellcome Sanger InstituteHinxtonUnited Kingdom
| | - Katie Love
- Wellcome Sanger InstituteHinxtonUnited Kingdom
| | | | - Anna E Jeffreys
- Wellcome Trust Centre for Human Genetics, University of OxfordOxfordUnited Kingdom
| | - Kate Rowlands
- Wellcome Trust Centre for Human Genetics, University of OxfordOxfordUnited Kingdom
| | - Christina S Hubbart
- Wellcome Trust Centre for Human Genetics, University of OxfordOxfordUnited Kingdom
| | - Mehul Dhorda
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
- Worldwide Antimalarial Resistance Network (WWARN), Asia Regional CentreBangkokThailand
| | - Ranitha Vongpromek
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
- Worldwide Antimalarial Resistance Network (WWARN), Asia Regional CentreBangkokThailand
| | - Namfon Kotanan
- Faculty of Tropical Medicine, Mahidol UniversityBangkokThailand
| | - Phrutsamon Wongnak
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | - Jacob Almagro Garcia
- MRC Centre for Genomics and Global Health, Big Data Institute, Oxford UniversityOxfordUnited Kingdom
| | - Richard D Pearson
- Wellcome Sanger InstituteHinxtonUnited Kingdom
- MRC Centre for Genomics and Global Health, Big Data Institute, Oxford UniversityOxfordUnited Kingdom
| | | | | | | | - T Nguyen
- Wellcome Sanger InstituteHinxtonUnited Kingdom
| | - Jim Stalker
- Wellcome Sanger InstituteHinxtonUnited Kingdom
| | - Ben Jeffery
- MRC Centre for Genomics and Global Health, Big Data Institute, Oxford UniversityOxfordUnited Kingdom
| | | | - Kimberly J Johnson
- Wellcome Sanger InstituteHinxtonUnited Kingdom
- MRC Centre for Genomics and Global Health, Big Data Institute, Oxford UniversityOxfordUnited Kingdom
| | | | - Xin Hui S Chan
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | | | | | - Victoria Simpson
- Wellcome Sanger InstituteHinxtonUnited Kingdom
- MRC Centre for Genomics and Global Health, Big Data Institute, Oxford UniversityOxfordUnited Kingdom
| | | | - Kirk Rockett
- Wellcome Sanger InstituteHinxtonUnited Kingdom
- Wellcome Trust Centre for Human Genetics, University of OxfordOxfordUnited Kingdom
| | - Nicholas P Day
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | - Arjen M Dondorp
- Centre for Tropical Medicine and Global Health, University of OxfordOxfordUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
| | - Dominic P Kwiatkowski
- Wellcome Sanger InstituteHinxtonUnited Kingdom
- MRC Centre for Genomics and Global Health, Big Data Institute, Oxford UniversityOxfordUnited Kingdom
| | - Olivo Miotto
- Wellcome Sanger InstituteHinxtonUnited Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit, Mahidol UniversityBangkokThailand
- MRC Centre for Genomics and Global Health, Big Data Institute, Oxford UniversityOxfordUnited Kingdom
| |
Collapse
|
15
|
Whitlock AOB, Juliano JJ, Mideo N. Immune selection suppresses the emergence of drug resistance in malaria parasites but facilitates its spread. PLoS Comput Biol 2021; 17:e1008577. [PMID: 34280179 PMCID: PMC8321109 DOI: 10.1371/journal.pcbi.1008577] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 07/29/2021] [Accepted: 06/04/2021] [Indexed: 12/23/2022] Open
Abstract
Although drug resistance in Plasmodium falciparum typically evolves in regions of low transmission, resistance spreads readily following introduction to regions with a heavier disease burden. This suggests that the origin and the spread of resistance are governed by different processes, and that high transmission intensity specifically impedes the origin. Factors associated with high transmission, such as highly immune hosts and competition within genetically diverse infections, are associated with suppression of resistant lineages within hosts. However, interactions between these factors have rarely been investigated and the specific relationship between adaptive immunity and selection for resistance has not been explored. Here, we developed a multiscale, agent-based model of Plasmodium parasites, hosts, and vectors to examine how host and parasite dynamics shape the evolution of resistance in populations with different transmission intensities. We found that selection for antigenic novelty (“immune selection”) suppressed the evolution of resistance in high transmission settings. We show that high levels of population immunity increased the strength of immune selection relative to selection for resistance. As a result, immune selection delayed the evolution of resistance in high transmission populations by allowing novel, sensitive lineages to remain in circulation at the expense of the spread of a resistant lineage. In contrast, in low transmission settings, we observed that resistant strains were able to sweep to high population prevalence without interference. Additionally, we found that the relationship between immune selection and resistance changed when resistance was widespread. Once resistance was common enough to be found on many antigenic backgrounds, immune selection stably maintained resistant parasites in the population by allowing them to proliferate, even in untreated hosts, when resistance was linked to a novel epitope. Our results suggest that immune selection plays a role in the global pattern of resistance evolution. Drug resistance in the malaria parasite, Plasmodium falciparum, presents an ongoing public health challenge, but aspects of its evolution are poorly understood. Although antimalarial resistance is common worldwide, it can typically be traced to just a handful of evolutionary origins. Counterintuitively, although Sub Saharan Africa bears 90% of the global malaria burden, resistance typically originates in regions where transmission intensity is low. In high transmission regions, infections are genetically diverse, and hosts have significant standing adaptive immunity, both of which are known to suppress the frequency of resistance within infections. However, interactions between immune-driven selection, transmission intensity, and resistance have not been investigated. Using a multiscale, agent-based model, we found that high transmission intensity slowed the evolution of resistance via its effect on host population immunity. High host immunity strengthened selection for antigenic novelty, interfering with selection for resistance and allowing sensitive lineages to suppress resistant lineages in untreated hosts. However, once resistance was common in the circulating parasite population, immune selection maintained it in the population at a high prevalence. Our findings provide a novel explanation for observations about the origin of resistance and suggest that adaptive immunity is a critical component of selection.
Collapse
Affiliation(s)
| | - Jonathan J. Juliano
- Division of Infectious Diseases, School of Medicine, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Nicole Mideo
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Canada
| |
Collapse
|
16
|
Kyei-Baafour E, Oppong M, Kusi KA, Frempong AF, Aculley B, Arthur FKN, Tiendrebeogo RW, Singh SK, Theisen M, Kweku M, Adu B, Hviid L, Ofori MF. Suitability of IgG responses to multiple Plasmodium falciparum antigens as markers of transmission intensity and pattern. PLoS One 2021; 16:e0249936. [PMID: 33886601 PMCID: PMC8062017 DOI: 10.1371/journal.pone.0249936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/27/2021] [Indexed: 12/05/2022] Open
Abstract
Detection of antibody reactivity to appropriate, specific parasite antigens may constitute a sensitive and cost-effective alternative to current tools to monitor malaria transmission across different endemicity settings. This study aimed to determine the suitability of IgG responses to a number of P. falciparum antigens as markers of transmission intensity and pattern. Antibody responses to multiple malaria antigens were determined in 905 participants aged 1–12 years from three districts with low (Keta), medium (Hohoe) and high (Krachi) transmission intensity in the Volta region of Ghana. Blood film microscopy slides and dry blood spots (DBS) were obtained for parasitaemia detection and antibody measurement, respectively. Sera were eluted from DBS and levels of IgG specific for 10 malaria antigens determined by a multiplex assay. Results were compared within and among the districts. Total IgG responses to MSPDBL1, MSPDBLLeucine, MSP2-FC27, RAMA, and PfRh2a and PfRh2b were higher in Krachi than in Hohoe and Keta. Seroprevalence of IgG specific for MSPDBLLeucine, RON4, and PfRh2b were also highest in Krachi. Responses to RALP-1, PfRh2a and PfRh2b were associated with patent but asymptomatic parasitaemia in Keta, while responses to MSPDBL1, MSPDBLLeucine, MSP2-FC27, RAMA, Rh2-2030, and PfRh2b were associated with parasite carriage in Hohoe, but not in Krachi. Using ROC analysis, only PfRh2b was found to predict patent, but asymptomatic, parasitaemia in Keta and Hohoe. Antibody breadth correlated positively with age (r = 0.29, p<0.0001) and parasitaemia (β = 3.91; CI = 1.53 to 6.29), and medium to high transmission (p<0.0001). Our findings suggest differences in malaria-specific antibody responses across the three transmission zones and that PfRh2b has potential as a marker of malaria transmission intensity and pattern. This could have implications for malaria control programs and vaccine trials.
Collapse
Affiliation(s)
- Eric Kyei-Baafour
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
- Department of Biochemistry and Biotechnology, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Mavis Oppong
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Hohoe, Ghana
| | - Kwadwo Asamoah Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Abena Fremaah Frempong
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Belinda Aculley
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Fareed K. N. Arthur
- Department of Biochemistry and Biotechnology, College of Science, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Regis Wendpayangde Tiendrebeogo
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, and at Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Susheel K. Singh
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, and at Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | - Michael Theisen
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, and at Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | - Margaret Kweku
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Hohoe, Ghana
| | - Bright Adu
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Lars Hviid
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, and at Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Michael Fokuo Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
- * E-mail:
| |
Collapse
|
17
|
Unwin HJT, Routledge I, Flaxman S, Rizoiu MA, Lai S, Cohen J, Weiss DJ, Mishra S, Bhatt S. Using Hawkes Processes to model imported and local malaria cases in near-elimination settings. PLoS Comput Biol 2021; 17:e1008830. [PMID: 33793564 PMCID: PMC8043404 DOI: 10.1371/journal.pcbi.1008830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 04/13/2021] [Accepted: 02/23/2021] [Indexed: 01/29/2023] Open
Abstract
Developing new methods for modelling infectious diseases outbreaks is important for monitoring transmission and developing policy. In this paper we propose using semi-mechanistic Hawkes Processes for modelling malaria transmission in near-elimination settings. Hawkes Processes are well founded mathematical methods that enable us to combine the benefits of both statistical and mechanistic models to recreate and forecast disease transmission beyond just malaria outbreak scenarios. These methods have been successfully used in numerous applications such as social media and earthquake modelling, but are not yet widespread in epidemiology. By using domain-specific knowledge, we can both recreate transmission curves for malaria in China and Eswatini and disentangle the proportion of cases which are imported from those that are community based.
Collapse
Affiliation(s)
- H. Juliette T. Unwin
- MRC Centre for Global Infectious Disease Analysis, Jameel Institute for Disease and Emergency Analytics, Imperial College, London, United Kingdom
| | - Isobel Routledge
- MRC Centre for Global Infectious Disease Analysis, Jameel Institute for Disease and Emergency Analytics, Imperial College, London, United Kingdom
- Department of Medicine, University of California, San Francisco, California, United States of America
| | - Seth Flaxman
- Department of Mathematics, Imperial College, London, United Kingdom
| | | | - Shengjie Lai
- WorldPop, School of Geography and Environmental Science, University of Southampton, Southampton, United Kingdom
| | - Justin Cohen
- Clinton Health Access Initiative, Boston, Massachusetts, United States of America
| | - Daniel J. Weiss
- Malaria Atlas Project, Big Data Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Telethon Kids Institute, Perth Children’s Hospital, Nedlands, Western Australia, Australia
- Curtin University, Bentley, Western Australia, Australia
| | - Swapnil Mishra
- MRC Centre for Global Infectious Disease Analysis, Jameel Institute for Disease and Emergency Analytics, Imperial College, London, United Kingdom
| | - Samir Bhatt
- MRC Centre for Global Infectious Disease Analysis, Jameel Institute for Disease and Emergency Analytics, Imperial College, London, United Kingdom
| |
Collapse
|
18
|
Mitchell RM, Zhou Z, Sheth M, Sergent S, Frace M, Nayak V, Hu B, Gimnig J, Ter Kuile F, Lindblade K, Slutsker L, Hamel MJ, Desai M, Otieno K, Kariuki S, Vigfusson Y, Shi YP. Development of a new barcode-based, multiplex-PCR, next-generation-sequencing assay and data processing and analytical pipeline for multiplicity of infection detection of Plasmodium falciparum. Malar J 2021; 20:92. [PMID: 33593329 PMCID: PMC7885407 DOI: 10.1186/s12936-021-03624-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 02/04/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Simultaneous infection with multiple malaria parasite strains is common in high transmission areas. Quantifying the number of strains per host, or the multiplicity of infection (MOI), provides additional parasite indices for assessing transmission levels but it is challenging to measure accurately with current tools. This paper presents new laboratory and analytical methods for estimating the MOI of Plasmodium falciparum. METHODS Based on 24 single nucleotide polymorphisms (SNPs) previously identified as stable, unlinked targets across 12 of the 14 chromosomes within P. falciparum genome, three multiplex PCRs of short target regions and subsequent next generation sequencing (NGS) of the amplicons were developed. A bioinformatics pipeline including B4Screening pathway removed spurious amplicons to ensure consistent frequency calls at each SNP location, compiled amplicons by SNP site diversity, and performed algorithmic haplotype and strain reconstruction. The pipeline was validated by 108 samples generated from cultured-laboratory strain mixtures in different proportions and concentrations, with and without pre-amplification, and using whole blood and dried blood spots (DBS). The pipeline was applied to 273 smear-positive samples from surveys conducted in western Kenya, then providing results into StrainRecon Thresholding for Infection Multiplicity (STIM), a novel MOI estimator. RESULTS The 24 barcode SNPs were successfully identified uniformly across the 12 chromosomes of P. falciparum in a sample using the pipeline. Pre-amplification and parasite concentration, while non-linearly associated with SNP read depth, did not influence the SNP frequency calls. Based on consistent SNP frequency calls at targeted locations, the algorithmic strain reconstruction for each laboratory-mixed sample had 98.5% accuracy in dominant strains. STIM detected up to 5 strains in field samples from western Kenya and showed declining MOI over time (q < 0.02), from 4.32 strains per infected person in 1996 to 4.01, 3.56 and 3.35 in 2001, 2007 and 2012, and a reduction in the proportion of samples with 5 strains from 57% in 1996 to 18% in 2012. CONCLUSION The combined approach of new multiplex PCRs and NGS, the unique bioinformatics pipeline and STIM could identify 24 barcode SNPs of P. falciparum correctly and consistently. The methodology could be applied to field samples to reliably measure temporal changes in MOI.
Collapse
Affiliation(s)
- Rebecca M Mitchell
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
- Department of Computer Science, Emory University, Atlanta, USA
- School of Nursing, Emory University, Atlanta, USA
| | - Zhiyong Zhou
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Mili Sheth
- Biotechnology Core Facility Branch, Division of Scientific Resources, CDC, Atlanta, USA
| | - Sheila Sergent
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Michael Frace
- Biotechnology Core Facility Branch, Division of Scientific Resources, CDC, Atlanta, USA
| | - Vishal Nayak
- Office of Infectious Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC, Atlanta, USA
| | - Bin Hu
- Office of Infectious Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC, Atlanta, USA
| | - John Gimnig
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | | | - Kim Lindblade
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Laurence Slutsker
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Mary J Hamel
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Meghna Desai
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA
| | - Kephas Otieno
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Simon Kariuki
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Ymir Vigfusson
- Department of Computer Science, Emory University, Atlanta, USA.
| | - Ya Ping Shi
- Division of Parasitic Diseases, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, USA.
| |
Collapse
|
19
|
Dambach P, Traoré I, Sawadogo H, Zabré P, Shukla S, Sauerborn R, Becker N, Phalkey R. Community acceptance of environmental larviciding against malaria with Bacillus thuringiensis israelensis in rural Burkina Faso - A knowledge, attitudes and practices study. Glob Health Action 2021; 14:1988279. [PMID: 34927578 PMCID: PMC8725727 DOI: 10.1080/16549716.2021.1988279] [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] [Indexed: 11/05/2022] Open
Abstract
Background Malaria control is based on early treatment of cases and on vector control. The current measures for malaria vector control in Africa are mainly based on long-lasting insecticidal nets (LLINs) and to a much smaller extent on indoor residual spraying (IRS). While bed net use is widely distributed and its role is intensively researched, Bti-based larviciding is a relatively novel tool in Africa. In this study, we analyze the perception and acceptability of Bti-based larval source management under different larviciding scenarios that were performed in a health district in Burkina Faso. Objective To research people’s perception and acceptance regarding biological larviciding interventions against malaria in their communities. Methods A cross-sectional study was undertaken using a total of 634 administered questionnaires. Data were collected in a total of 36 rural villages and in seven town quarters of the semi-urban town of Nouna. Results Respondents had basic to good knowledge regarding malaria transmission and how to protect oneself against it. More than 90% reported sleeping under a bed net, while other measures such as mosquito coils and insecticides were only used by a minority. The majority of community members reported high perceived reductions in mosquito abundance and the number of malaria episodes. There was a high willingness to contribute financially to larviciding interventions among interviewees. Conclusions This study showed that biological larviciding interventions are welcomed by the population that they are regarded as an effective and safe means to reduce mosquito abundance and malaria transmission. A routine implementation would, despite low intervention costs, require community ownership and contribution.
Collapse
Affiliation(s)
- Peter Dambach
- Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany
| | - Issouf Traoré
- Centre De Recherche En Santé De Nouna, Nouna, Burkina Faso.,Institut De Formations Initiale Et Continue, Université Thomas Sankara, Ouagadougou, Burkina Faso
| | | | - Pascal Zabré
- Centre De Recherche En Santé De Nouna, Nouna, Burkina Faso
| | - Sharvari Shukla
- Symbiosis Statistical Institute, Symbiosis International (Deemed University)
| | - Rainer Sauerborn
- Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany
| | - Norbert Becker
- German Mosquito Control Association (KABS), Speyer, Germany.,Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Revati Phalkey
- Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany.,Epidemiology and Public Health Division, University of Nottingham, Nottingham, UK.,Climate Change and Health Group, Public Health England, Chilton, UK
| |
Collapse
|
20
|
A New Test of a Theory about Old Mosquitoes. Trends Parasitol 2020; 37:185-194. [PMID: 33250441 DOI: 10.1016/j.pt.2020.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 10/26/2020] [Accepted: 10/26/2020] [Indexed: 11/24/2022]
Abstract
In vector control, it is widely accepted that killing adult mosquitoes would sharply reduce the proportion of old mosquitoes and cause the greatest changes to malaria transmission. The principle is based on a mathematical model of the sporozoite rate (the proportion of infective mosquitoes) that emphasized changes in mosquito age. Killing adult mosquitoes also reduces mosquito population densities, which are directly proportional to human biting rates (the number of bites, per person, per day). Eect sizes of vector control can be compared using sporozoite rates and human biting rates, which are commonly measured. We argue that human biting rates convey more use- ful information for planning, monitoring and evaluating vector control, and operational research should focus on understanding mosquito ecology.
Collapse
|
21
|
Adeniji E, Asante KP, Boahen O, Compaoré G, Coulibaly B, Kaali S, Kabore Y, Lamy M, Lusingu J, Malabeja A, Mens P, Orsini M, Otieno L, Otieno W, Owusu-Agyei S, Oyieko J, Pirçon JY, Praet N, Roman F, Sie A, Sing’oei V, Sirima SB, Sylla K, Tine R, Tiono AB, Tivura M, Usuf E, Wéry S. Estimating Annual Fluctuations in Malaria Transmission Intensity and in the Use of Malaria Control Interventions in Five Sub-Saharan African Countries. Am J Trop Med Hyg 2020; 103:1883-1892. [PMID: 32959764 PMCID: PMC7646796 DOI: 10.4269/ajtmh.19-0795] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 08/07/2020] [Indexed: 11/08/2022] Open
Abstract
RTS,S/AS01E malaria vaccine safety, effectiveness, and impact will be assessed in pre- and post-vaccine introduction studies, comparing the occurrence of malaria cases and adverse events in vaccinated versus unvaccinated children. Because those comparisons may be confounded by potential year-to-year fluctuations in malaria transmission intensity and malaria control intervention usage, the latter should be carefully monitored to adequately adjust the analyses. This observational cross-sectional study is assessing Plasmodium falciparum parasite prevalence (PfPR) and malaria control intervention usage over nine annual surveys performed at peak parasite transmission. Plasmodium falciparum parasite prevalence was measured by microscopy and nucleic acid amplification test (quantitative PCR) in parallel in all participants, and defined as the proportion of infected participants among participants tested. Results of surveys 1 (S1) and 2 (S2), conducted in five sub-Saharan African countries, including some participating in the Malaria Vaccine Implementation Programme (MVIP), are reported herein; 4,208 and 4,199 children were, respectively, included in the analyses. Plasmodium falciparum parasite prevalence estimated using microscopy varied between study sites in both surveys, with the lowest prevalence in Senegalese sites and the highest in Burkina Faso. In sites located in the MVIP areas (Kintampo and Kombewa), PfPR in children aged 6 months to 4 years ranged from 24.8% to 27.3%, depending on the study site and the survey. Overall, 89.5% and 86.4% of children used a bednet in S1 and S2, of whom 68.7% and 77.9% used impregnated bednets. No major difference was observed between the two surveys in terms of PfPR or use of malaria control interventions.
Collapse
Affiliation(s)
- RTS,S Epidemiology EPI-MAL-005 Study Group The RTS,S Epidemiology EPI-MAL-005 study group is composed of (per alphabetical order):
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou, Burkina Faso
- Aixial c/o GSK, Wavre, Belgium
- National Institute for Medical Research (NIMR), Korogwe, Tanzania
- University of Copenhagen, Copenhagen, Denmark
- Parasitology Unit, Department of Medical Microbiology, Academic Medical Center, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
- 4Clinics c/o GSK, Wavre, Belgium
- KEMRI - Walter Reed Project, US Army Medical Research Directorate-Kenya, Kombewa, Kenya
- GSK, Wavre, Belgium
- Département de Parasitologie, Centre de Recherche de Keur Socé, Faculté de Médecine, Université Cheikh Anta Diop, Dakar, Senegal
- Medical Research Council Unit, The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Elisha Adeniji
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | - Kwaku Poku Asante
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | - Owusu Boahen
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | | | | | - Seyram Kaali
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | - Youssouf Kabore
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou, Burkina Faso
| | | | - John Lusingu
- National Institute for Medical Research (NIMR), Korogwe, Tanzania
- University of Copenhagen, Copenhagen, Denmark
| | | | - Petra Mens
- Parasitology Unit, Department of Medical Microbiology, Academic Medical Center, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Lucas Otieno
- KEMRI - Walter Reed Project, US Army Medical Research Directorate-Kenya, Kombewa, Kenya
| | - Walter Otieno
- KEMRI - Walter Reed Project, US Army Medical Research Directorate-Kenya, Kombewa, Kenya
| | - Seth Owusu-Agyei
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | - Janet Oyieko
- KEMRI - Walter Reed Project, US Army Medical Research Directorate-Kenya, Kombewa, Kenya
| | | | | | | | - Ali Sie
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | - Valentine Sing’oei
- KEMRI - Walter Reed Project, US Army Medical Research Directorate-Kenya, Kombewa, Kenya
| | - Sodiomon B. Sirima
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou, Burkina Faso
| | - Khadime Sylla
- Département de Parasitologie, Centre de Recherche de Keur Socé, Faculté de Médecine, Université Cheikh Anta Diop, Dakar, Senegal
| | - Roger Tine
- Département de Parasitologie, Centre de Recherche de Keur Socé, Faculté de Médecine, Université Cheikh Anta Diop, Dakar, Senegal
| | - Alfred B. Tiono
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou, Burkina Faso
| | - Mathilda Tivura
- Kintampo Health Research Centre, Ghana Health Service, Kintampo, Ghana
| | - Effua Usuf
- Medical Research Council Unit, The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | | |
Collapse
|
22
|
Adugna T, Getu E, Yewhalaw D. Species diversity and distribution of Anopheles mosquitoes in Bure district, Northwestern Ethiopia. Heliyon 2020; 6:e05063. [PMID: 33102831 PMCID: PMC7569303 DOI: 10.1016/j.heliyon.2020.e05063] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 05/14/2020] [Accepted: 09/22/2020] [Indexed: 11/18/2022] Open
Abstract
Malaria is one the leading health problem of the Ethiopia. Previously, areas above 2,000 m elevation were considered as malaria free areas. However, the major malaria epidemics were seen in areas at an altitude up to 3,000 m above sea level. These epidemics were due to climate and land-use changes (ecological changes) and still malaria is a growing health problem in highland parts of Ethiopia. This study aimed to investigate the species diversity, abundance and distribution of Anopheles mosquitoes in highland fringe of Bure district, Northwestern Ethiopia. It was done in the three different agroecological villages, Bukta (Irrigated), Workimdr (non-irrigated with few dry season breeding habitats) and Shnebekuma (non-irrigated with many dry season breeding habitats). Anopheles mosquitoes were collected by the Centers for Disease Control and Prevention Light Traps Catches, Pyrethrum Spray Catches, and Artificial Pit Shelters (APSs) from twenty-seven houses, thirty houses, and six APSs, respectively. Anopheles mosquitoes were identified morphologically to species using standard keys. Furthermore, molecular identification of Anopheles gambiae s.l was carried out using species-specific Polymerase Chain Reaction. Independent T-Test and One-way- ANOVA were employed to compare the mean mosquito's density between villages and species, indoor and outdoor host seeking mosquitoes. Descriptive statistic was used to calculate the proportion of each Anopheles species. Nine Anopheles mosquito species were identified in the study area which includes: Anopheles demeilloni, An. arabiensis, An. funestus group, An. coustani, An. squamosus, An. cinereus, An. pharoensis, An. rupicolus, and An. natalensis. Of the 4,703 Anopheles mosquitoes collected, An. demeilloni was the most prominent (50.7%, n = 2383) whereas An. rupicolus (0.03%, n = 3), and An. natalensis (0.02%, n = 1) were the least abundant. Higher mean density of Anopheles mosquitoes was collected from the non-irrigated village (2.395 ± 0.100) than irrigated (1.351 ± 0.109) (p = 0.001). In conclusion, three of the most important malaria vectors (An. arabiensis, An. funestus group and An. pharoensis) of Ethiopia were recorded in the study sites, especially the first two was found thought-out the year. Most of the Anopheles mosquitoes were collected from non-irrigated villages. Thus, breeding habitat management must be practiced throughout the year together with long-lasting insecticide-treated nets and insecticide residual sprays.
Collapse
Affiliation(s)
- Tilahun Adugna
- Debre Tabor University, P.O. Box: 272, Debre Tabor, Ethiopia
| | - Emana Getu
- Addis Ababa University, P.O. Box: 2003, Addis Ababa, Ethiopia
| | | |
Collapse
|
23
|
Mordecai EA, Ryan SJ, Caldwell JM, Shah MM, LaBeaud AD. Climate change could shift disease burden from malaria to arboviruses in Africa. Lancet Planet Health 2020; 4:e416-e423. [PMID: 32918887 PMCID: PMC7490804 DOI: 10.1016/s2542-5196(20)30178-9] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 05/28/2023]
Abstract
Malaria is a long-standing public health problem in sub-Saharan Africa, whereas arthropod-borne viruses (arboviruses) such as dengue and chikungunya cause an under-recognised burden of disease. Many human and environmental drivers affect the dynamics of vector-borne diseases. In this Personal View, we argue that the direct effects of warming temperatures are likely to promote greater environmental suitability for dengue and other arbovirus transmission by Aedes aegypti and reduce suitability for malaria transmission by Anopheles gambiae. Environmentally driven changes in disease dynamics will be complex and multifaceted, but given that current public efforts are targeted to malaria control, we highlight Ae aegypti and dengue, chikungunya, and other arboviruses as potential emerging public health threats in sub-Saharan Africa.
Collapse
Affiliation(s)
- Erin A. Mordecai
- Biology Department, Stanford University, 371 Serra Mall, Stanford, CA, United States
| | - Sadie J. Ryan
- Department of Geography, University of Florida, Gainesville, FL, United States; Emerging Pathogens Institute, University of Florida, Gainesville, FL, United States; School of Life Sciences, College of Agriculture, Engineering, and Science, University of KwaZulu Natal, KwaZulu Natal, South Africa
| | - Jamie M. Caldwell
- Biology Department, Stanford University, 371 Serra Mall, Stanford, CA, United States
| | - Melisa M. Shah
- Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | - A. Desiree LaBeaud
- Department of Pediatrics, Division of Infectious Disease, School of Medicine, Stanford University, Stanford, CA, United States
| |
Collapse
|
24
|
Guerra CA, Fuseini G, Donfack OT, Smith JM, Ondo Mifumu TA, Akadiri G, Eyang DEM, Eburi CO, Motobe Vaz L, Micha VM, Okenve LA, Janes CR, Andeme RM, Rivas MR, Phiri WP, Slotman MA, Smith DL, García GA. Malaria outbreak in Riaba district, Bioko Island: lessons learned. Malar J 2020; 19:277. [PMID: 32746919 PMCID: PMC7398070 DOI: 10.1186/s12936-020-03347-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/25/2020] [Indexed: 11/18/2022] Open
Abstract
At the beginning of 2019, a sudden surge of malaria cases was observed in the district of Riaba, Bioko Island. Between January and April, confirmed malaria cases increased 3.8-fold compared to the same period in 2018. Concurrently, anopheline human biting rate (HBR) increased 2.1-fold. During the outbreak, 82.2% of the district population was tested for malaria with a rapid diagnostic test; 37.2% of those tested had a detectable infection and were treated according to national guidelines. Vector control interventions, including indoor residual spraying and larval source management were scaled-up. After the interventions, the number of confirmed cases decreased by 70% and the overall parasite prevalence in the communities by 43.8%. Observed prevalence in a follow up malaria indicator survey, however, was significantly higher than elsewhere on the island, and higher than in previous years. There was no significant reduction in HBR, which remained high for the rest of the year. The surge was attributed to various factors, chiefly increased rainfall and a large number of anthropogenic anopheline breeding sites created by construction works. This case study highlights the need for sustained vector control interventions and multi-sector participation, particularly in malaria control and elimination settings with persistently high local malaria receptivity.
Collapse
Affiliation(s)
- Carlos A Guerra
- Medical Care Development International, 8401 Colesville Road, Suite 425, Silver Spring, MD, 20910, USA
| | - Godwin Fuseini
- MedicalCare Development International, Av. Parques de Africa, Malabo, Equatorial Guinea
| | | | - Jordan M Smith
- MedicalCare Development International, Av. Parques de Africa, Malabo, Equatorial Guinea
| | - Teresa Ayingono Ondo Mifumu
- MedicalCare Development International, Av. Parques de Africa, Malabo, Equatorial Guinea.,National Malaria Control Programme, Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Gninoussa Akadiri
- MedicalCare Development International, Av. Parques de Africa, Malabo, Equatorial Guinea
| | - Delicias Esono Mba Eyang
- MedicalCare Development International, Av. Parques de Africa, Malabo, Equatorial Guinea.,National Malaria Control Programme, Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Consuelo Oki Eburi
- MedicalCare Development International, Av. Parques de Africa, Malabo, Equatorial Guinea.,National Malaria Control Programme, Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Liberato Motobe Vaz
- MedicalCare Development International, Av. Parques de Africa, Malabo, Equatorial Guinea
| | - Victor Mba Micha
- MedicalCare Development International, Av. Parques de Africa, Malabo, Equatorial Guinea
| | - Leonor Ada Okenve
- MedicalCare Development International, Av. Parques de Africa, Malabo, Equatorial Guinea.,National Malaria Control Programme, Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Christopher R Janes
- Department of Entomology, Texas A&M University, TAMU 2475, College Station, TX, 77843, USA
| | - Ramona Mba Andeme
- National Malaria Control Programme, Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Matilde Riloha Rivas
- National Malaria Control Programme, Ministry of Health and Social Welfare, Malabo, Equatorial Guinea
| | - Wonder P Phiri
- MedicalCare Development International, Av. Parques de Africa, Malabo, Equatorial Guinea
| | - Michel A Slotman
- Department of Entomology, Texas A&M University, TAMU 2475, College Station, TX, 77843, USA
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, 2301 Fifth Avenue, Seattle, WA, 98121, USA
| | - Guillermo A García
- Medical Care Development International, 8401 Colesville Road, Suite 425, Silver Spring, MD, 20910, USA.
| |
Collapse
|
25
|
Hoi AG, Gilbert B, Mideo N. Deconstructing the Impact of Malaria Vector Diversity on Disease Risk. Am Nat 2020; 196:E61-E70. [PMID: 32813999 DOI: 10.1086/710005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractRecent years have seen significant progress in understanding the impact of host community assemblage on disease risk, yet diversity in disease vectors has rarely been investigated. Using published malaria and mosquito surveys from Kenya, we analyzed the relationship between malaria prevalence and multiple axes of mosquito diversity: abundance, species richness, and composition. We found a net amplification of malaria prevalence by vector species richness, a result of a strong direct positive association between richness and prevalence alongside a weak indirect negative association between the two, mediated through mosquito community composition. One plausible explanation of these patterns is species niche complementarity, whereby less competent vector species contribute to disease transmission by filling spatial or temporal gaps in transmission left by dominant vectors. A greater understanding of vector community assemblage and function, as well as any interactions between host and vector biodiversity, could offer insights to both fundamental and applied ecology.
Collapse
|
26
|
Degefa T, Yewhalaw D, Zhou G, Atieli H, Githeko AK, Yan G. Evaluation of human-baited double net trap and human-odour-baited CDC light trap for outdoor host-seeking malaria vector surveillance in Kenya and Ethiopia. Malar J 2020; 19:174. [PMID: 32381009 PMCID: PMC7206766 DOI: 10.1186/s12936-020-03244-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/23/2020] [Indexed: 11/19/2022] Open
Abstract
Background Surveillance of outdoor host-seeking malaria vectors is crucial to monitor changes in vector biting behaviour and evaluate the impact of vector control interventions. Human landing catch (HLC) has been considered the most reliable and gold standard surveillance method to estimate human-biting rates. However, it is labour-intensive, and its use is facing an increasing ethical concern due to potential risk of exposure to infectious mosquito bites. Thus, alternative methods are required. This study was conducted to evaluate the performance of human-odour-baited CDC light trap (HBLT) and human-baited double net trap (HDNT) for outdoor host-seeking malaria vector surveillance in Kenya and Ethiopia. Methods The sampling efficiency of HBLT and HDNT was compared with CDC light trap and HLC using Latin Square Design in Ahero and Iguhu sites, western Kenya and Bulbul site, southwestern Ethiopia between November 2015 and December 2018. The differences in Anopheles mosquito density among the trapping methods were compared using generalized linear model. Results Overall, 16,963 female Anopheles mosquitoes comprising Anopheles gambiae sensu lato (s.l.), Anopheles funestus s.l., Anopheles pharoensis, Anopheles coustani and Anopheles squamosus were collected. PCR results (n = 552) showed that Anopheles arabiensis was the only member of An. gambiae s.l. in Ahero and Bulbul, while 15.7% An. arabiensis and 84.3% An. gambiae sensu stricto (s.s.) constituted An. gambiae s.l. in Iguhu. In Ahero, HBLT captured 2.23 times as many An. arabiensis and 2.11 times as many An. funestus as CDC light trap. In the same site, HDNT yielded 3.43 times more An. arabiensis and 3.24 times more An. funestus than HBLT. In Iguhu, the density of Anopheles mosquitoes did not vary between the traps (p > 0.05). In Bulbul, HBLT caught 2.19 times as many An. arabiensis as CDC light trap, while HDNT caught 6.53 times as many An. arabiensis as CDC light trap. The mean density of An. arabiensis did not vary between HDNT and HLC (p = 0.098), whereas the HLC yielded significantly higher density of An. arabiensis compared to HBLT and CDC light trap. There was a significant density-independent positive correlation between HDNT and HLC (r = 0.69). Conclusion This study revealed that both HBLT and HDNT caught higher density of malaria vectors than conventional CDC light trap. Moreover, HDNT yielded a similar vector density as HLC, suggesting that it could be an alternative tool to HLC for outdoor host-seeking malaria vector surveillance.
Collapse
Affiliation(s)
- Teshome Degefa
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia. .,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.,Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Guofa Zhou
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| | - Harrysone Atieli
- School of Public Health and Community Development, Maseno University, Kisumu, Kenya
| | - Andrew K Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Guiyun Yan
- Program in Public Health, College of Health Sciences, University of California at Irvine, Irvine, CA, 92697, USA
| |
Collapse
|
27
|
Monthly Entomological Inoculation Rate Data for Studying the Seasonality of Malaria Transmission in Africa. DATA 2020. [DOI: 10.3390/data5020031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A comprehensive literature review was conducted to create a new database of 197 field surveys of monthly malaria Entomological Inoculation Rates (EIR), a metric of malaria transmission intensity. All field studies provide data at a monthly temporal resolution and have a duration of at least one year in order to study the seasonality of the disease. For inclusion, data collection methodologies adhered to a specific standard and the location and timing of the measurements were documented. Auxiliary information on the population and hydrological setting were also included. The database includes measurements that cover West and Central Africa and the period from 1945 to 2011, and hence facilitates analysis of interannual transmission variability over broad regions.
Collapse
|
28
|
Singh KS, Leu JIJ, Barnoud T, Vonteddu P, Gnanapradeepan K, Lin C, Liu Q, Barton JC, Kossenkov AV, George DL, Murphy ME, Dotiwala F. African-centric TP53 variant increases iron accumulation and bacterial pathogenesis but improves response to malaria toxin. Nat Commun 2020; 11:473. [PMID: 31980600 PMCID: PMC6981190 DOI: 10.1038/s41467-019-14151-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 12/17/2019] [Indexed: 11/09/2022] Open
Abstract
A variant at amino acid 47 in human TP53 exists predominantly in individuals of African descent. P47S human and mouse cells show increased cancer risk due to defective ferroptosis. Here, we show that this ferroptotic defect causes iron accumulation in P47S macrophages. This high iron content alters macrophage cytokine profiles, leads to higher arginase level and activity, and decreased nitric oxide synthase activity. This leads to more productive intracellular bacterial infections but is protective against malarial toxin hemozoin. Proteomics of macrophages reveal decreased liver X receptor (LXR) activation, inflammation and antibacterial defense in P47S macrophages. Both iron chelators and LXR agonists improve the response of P47S mice to bacterial infection. African Americans with elevated saturated transferrin and serum ferritin show higher prevalence of the P47S variant (OR = 1.68 (95%CI 1.07–2.65) p = 0.023), suggestive of its role in iron accumulation in humans. This altered macrophage phenotype may confer an advantage in malaria-endemic sub-Saharan Africa. A polymorphism in human TP53 (P47S) that predominantly exists in individuals of African descent affects ferroptosis. Here, the authors show that this results in iron accumulation in macrophages leading to more productive infection by intracellular bacteria but improved anti-inflammatory response to the malarial toxin hemozoin.
Collapse
Affiliation(s)
- Kumar Sachin Singh
- Vaccine and Immunotherapy Center, The Wistar Institute, Philadelphia, PA, 19104, USA
| | - Julia I-Ju Leu
- Department of Genetics, The Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Thibaut Barnoud
- Program in Molecular and Cellular Oncogenesis, The Wistar Institute, Philadelphia, PA, 19104, USA
| | - Prashanthi Vonteddu
- Vaccine and Immunotherapy Center, The Wistar Institute, Philadelphia, PA, 19104, USA
| | - Keerthana Gnanapradeepan
- Program in Molecular and Cellular Oncogenesis, The Wistar Institute, Philadelphia, PA, 19104, USA.,Graduate Group in Biochemistry and Molecular Biophysics, The Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Cindy Lin
- Program in Immunology, Microenvironment and Metastasis, The Wistar Institute, Philadelphia, PA, 19104, USA
| | - Qin Liu
- Program in Molecular and Cellular Oncogenesis, The Wistar Institute, Philadelphia, PA, 19104, USA
| | - James C Barton
- Southern Iron Disorders Center, Birmingham AL 35209 USA and Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Andrew V Kossenkov
- Bioinformatics Facility, The Wistar Institute, Philadelphia, PA, 19104, USA
| | - Donna L George
- Department of Genetics, The Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Maureen E Murphy
- Program in Molecular and Cellular Oncogenesis, The Wistar Institute, Philadelphia, PA, 19104, USA.
| | - Farokh Dotiwala
- Vaccine and Immunotherapy Center, The Wistar Institute, Philadelphia, PA, 19104, USA.
| |
Collapse
|
29
|
Huestis DL, Dao A, Diallo M, Sanogo ZL, Samake D, Yaro AS, Ousman Y, Linton YM, Krishna A, Veru L, Krajacich BJ, Faiman R, Florio J, Chapman JW, Reynolds DR, Weetman D, Mitchell R, Donnelly MJ, Talamas E, Chamorro L, Strobach E, Lehmann T. Windborne long-distance migration of malaria mosquitoes in the Sahel. Nature 2019; 574:404-408. [PMID: 31578527 PMCID: PMC11095661 DOI: 10.1038/s41586-019-1622-4] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 09/06/2019] [Indexed: 11/09/2022]
Abstract
Over the past two decades efforts to control malaria have halved the number of cases globally, yet burdens remain high in much of Africa and the elimination of malaria has not been achieved even in areas where extreme reductions have been sustained, such as South Africa1,2. Studies seeking to understand the paradoxical persistence of malaria in areas in which surface water is absent for 3-8 months of the year have suggested that some species of Anopheles mosquito use long-distance migration3. Here we confirm this hypothesis through aerial sampling of mosquitoes at 40-290 m above ground level and provide-to our knowledge-the first evidence of windborne migration of African malaria vectors, and consequently of the pathogens that they transmit. Ten species, including the primary malaria vector Anopheles coluzzii, were identified among 235 anopheline mosquitoes that were captured during 617 nocturnal aerial collections in the Sahel of Mali. Notably, females accounted for more than 80% of all of the mosquitoes that we collected. Of these, 90% had taken a blood meal before their migration, which implies that pathogens are probably transported over long distances by migrating females. The likelihood of capturing Anopheles species increased with altitude (the height of the sampling panel above ground level) and during the wet seasons, but variation between years and localities was minimal. Simulated trajectories of mosquito flights indicated that there would be mean nightly displacements of up to 300 km for 9-h flight durations. Annually, the estimated numbers of mosquitoes at altitude that cross a 100-km line perpendicular to the prevailing wind direction included 81,000 Anopheles gambiae sensu stricto, 6 million A. coluzzii and 44 million Anopheles squamosus. These results provide compelling evidence that millions of malaria vectors that have previously fed on blood frequently migrate over hundreds of kilometres, and thus almost certainly spread malaria over these distances. The successful elimination of malaria may therefore depend on whether the sources of migrant vectors can be identified and controlled.
Collapse
Affiliation(s)
- Diana L Huestis
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Adama Dao
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
| | - Moussa Diallo
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
| | - Zana L Sanogo
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
| | - Djibril Samake
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
| | - Alpha S Yaro
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
- Faculte des Sciences et Techniques, Universite des Sciences des Techniques et des Technologies de Bamako (FSTUSTTB), Bamako, Mali
| | - Yossi Ousman
- Malaria Research and Training Center (MRTC), Faculty of Medicine, Pharmacy and Odonto-stomatology, University of Bamako, Bamako, Mali
| | - Yvonne-Marie Linton
- Walter Reed Biosystematics Unit, Smithsonian Institution Museum Support Center, Suitland, MD, USA
- Department of Entomology, Smithsonian Institution, National Museum of Natural History, Washington, DC, USA
| | - Asha Krishna
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Laura Veru
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | | | - Roy Faiman
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Jenna Florio
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA
| | - Jason W Chapman
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
- Environment and Sustainability Institute, University of Exeter, Penryn, UK
| | - Don R Reynolds
- Natural Resources Institute, University of Greenwich, Chatham, UK
- Rothamsted Research, Harpenden, UK
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Reed Mitchell
- Walter Reed Biosystematics Unit, Smithsonian Institution Museum Support Center, Suitland, MD, USA
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Elijah Talamas
- Systematic Entomology Laboratory - ARS, USDA, Smithsonian Institution National Museum of Natural History, Washington, DC, USA
- Florida Department of Agriculture and Consumer Services, Department of Plant Industry, Gainesville, FL, USA
| | - Lourdes Chamorro
- Department of Entomology, Smithsonian Institution, National Museum of Natural History, Washington, DC, USA
- Systematic Entomology Laboratory - ARS, USDA, Smithsonian Institution National Museum of Natural History, Washington, DC, USA
| | - Ehud Strobach
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
- Global Modeling and Assimilation Office, NASA GSFC, Greenbelt, MD, USA
| | - Tovi Lehmann
- Laboratory of Malaria and Vector Research, NIAID, NIH, Rockville, MD, USA.
| |
Collapse
|
30
|
Mordecai EA, Caldwell JM, Grossman MK, Lippi CA, Johnson LR, Neira M, Rohr JR, Ryan SJ, Savage V, Shocket MS, Sippy R, Stewart Ibarra AM, Thomas MB, Villena O. Thermal biology of mosquito-borne disease. Ecol Lett 2019; 22:1690-1708. [PMID: 31286630 PMCID: PMC6744319 DOI: 10.1111/ele.13335] [Citation(s) in RCA: 268] [Impact Index Per Article: 53.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/22/2019] [Accepted: 06/06/2019] [Indexed: 12/11/2022]
Abstract
Mosquito-borne diseases cause a major burden of disease worldwide. The vital rates of these ectothermic vectors and parasites respond strongly and nonlinearly to temperature and therefore to climate change. Here, we review how trait-based approaches can synthesise and mechanistically predict the temperature dependence of transmission across vectors, pathogens, and environments. We present 11 pathogens transmitted by 15 different mosquito species - including globally important diseases like malaria, dengue, and Zika - synthesised from previously published studies. Transmission varied strongly and unimodally with temperature, peaking at 23-29ºC and declining to zero below 9-23ºC and above 32-38ºC. Different traits restricted transmission at low versus high temperatures, and temperature effects on transmission varied by both mosquito and parasite species. Temperate pathogens exhibit broader thermal ranges and cooler thermal minima and optima than tropical pathogens. Among tropical pathogens, malaria and Ross River virus had lower thermal optima (25-26ºC) while dengue and Zika viruses had the highest (29ºC) thermal optima. We expect warming to increase transmission below thermal optima but decrease transmission above optima. Key directions for future work include linking mechanistic models to field transmission, combining temperature effects with control measures, incorporating trait variation and temperature variation, and investigating climate adaptation and migration.
Collapse
Affiliation(s)
- Erin A. Mordecai
- Department of BiologyStanford University371 Serra MallStanfordCAUSA
| | | | - Marissa K. Grossman
- Department of Entomology and Center for Infectious Disease DynamicsPenn State UniversityUniversity ParkPA16802USA
| | - Catherine A. Lippi
- Department of Geography and Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
| | - Leah R. Johnson
- Department of StatisticsVirginia Polytechnic and State University250 Drillfield DriveBlacksburgVAUSA
| | - Marco Neira
- Center for Research on Health in Latin America (CISeAL)Pontificia Universidad Católica del EcuadorQuitoEcuador
| | - Jason R. Rohr
- Department of Biological SciencesEck Institute of Global HealthEnvironmental Change InitiativeUniversity of Notre Dame, Notre DameINUSA
| | - Sadie J. Ryan
- Department of Geography and Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
- School of Life SciencesUniversity of KwaZulu‐NatalDurbanSouth Africa
| | - Van Savage
- Department of Ecology and Evolutionary Biology and Department of BiomathematicsUniversity of California Los AngelesLos AngelesCA90095USA
- Santa Fe Institute1399 Hyde Park RdSanta FeNM87501USA
| | - Marta S. Shocket
- Department of BiologyStanford University371 Serra MallStanfordCAUSA
| | - Rachel Sippy
- Department of Geography and Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
- Institute for Global Health and Translational SciencesSUNY Upstate Medical UniversitySyracuseNY13210USA
| | - Anna M. Stewart Ibarra
- Institute for Global Health and Translational SciencesSUNY Upstate Medical UniversitySyracuseNY13210USA
| | - Matthew B. Thomas
- Department of Entomology and Center for Infectious Disease DynamicsPenn State UniversityUniversity ParkPA16802USA
| | - Oswaldo Villena
- Department of StatisticsVirginia Polytechnic and State University250 Drillfield DriveBlacksburgVAUSA
| |
Collapse
|
31
|
Guerra CA, Kang SY, Citron DT, Hergott DEB, Perry M, Smith J, Phiri WP, Osá Nfumu JO, Mba Eyono JN, Battle KE, Gibson HS, García GA, Smith DL. Human mobility patterns and malaria importation on Bioko Island. Nat Commun 2019; 10:2332. [PMID: 31133635 PMCID: PMC6536527 DOI: 10.1038/s41467-019-10339-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 05/02/2019] [Indexed: 01/09/2023] Open
Abstract
Malaria burden on Bioko Island has decreased significantly over the past 15 years. The impact of interventions on malaria prevalence, however, has recently stalled. Here, we use data from island-wide, annual malaria indicator surveys to investigate human movement patterns and their relationship to Plasmodium falciparum prevalence. Using geostatistical and mathematical modelling, we find that off-island travel is more prevalent in and around the capital, Malabo. The odds of malaria infection among off-island travelers are significantly higher than the rest of the population. We estimate that malaria importation rates are high enough to explain malaria prevalence in much of Malabo and its surroundings, and that local transmission is highest along the West Coast of the island. Despite uncertainty, these estimates of residual transmission and importation serve as a basis for evaluating progress towards elimination and for efficiently allocating resources as Bioko makes the transition from control to elimination.
Collapse
Affiliation(s)
- Carlos A Guerra
- Medical Care Development International, 8401 Colesville Road, Suite 425, Silver Spring, MD, 20910, USA.
| | - Su Yun Kang
- Malaria Atlas Project, Big Data Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FY, UK
| | - Daniel T Citron
- Institute for Health Metrics and Evaluation, University of Washington, 2301 Fifth Ave., Suite 600, Seattle, WA, 98121, USA
| | - Dianna E B Hergott
- University of Washington, Department of Epidemiology, 1959 NE Pacific Street, Health Sciences Bldg, F-262, Box 357236, Seattle, WA, 98195, USA
| | - Megan Perry
- Medical Care Development International, 8401 Colesville Road, Suite 425, Silver Spring, MD, 20910, USA
| | - Jordan Smith
- Medical Care Development International, Avenida Parques de Africa S/N, Malabo, Equatorial Guinea
| | - Wonder P Phiri
- Medical Care Development International, Avenida Parques de Africa S/N, Malabo, Equatorial Guinea
| | - José O Osá Nfumu
- Medical Care Development International, Avenida Parques de Africa S/N, Malabo, Equatorial Guinea
| | - Jeremías N Mba Eyono
- Medical Care Development International, Avenida Parques de Africa S/N, Malabo, Equatorial Guinea
| | - Katherine E Battle
- Malaria Atlas Project, Big Data Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FY, UK
| | - Harry S Gibson
- Malaria Atlas Project, Big Data Institute, Nuffield Department of Medicine, University of Oxford, Roosevelt Drive, Oxford, OX3 7FY, UK
| | - Guillermo A García
- Medical Care Development International, 8401 Colesville Road, Suite 425, Silver Spring, MD, 20910, USA
| | - David L Smith
- Institute for Health Metrics and Evaluation, University of Washington, 2301 Fifth Ave., Suite 600, Seattle, WA, 98121, USA
| |
Collapse
|
32
|
Case Definitions of Clinical Malaria in Children from Three Health Districts in the North Region of Cameroon. BIOMED RESEARCH INTERNATIONAL 2019; 2019:9709013. [PMID: 31139663 PMCID: PMC6500661 DOI: 10.1155/2019/9709013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 02/26/2019] [Accepted: 03/20/2019] [Indexed: 12/05/2022]
Abstract
Malaria endemicity in Cameroon greatly varies according to ecological environment. In such conditions, parasitaemia, which is associated with fever, may not always suffice to define an episode of clinical malaria. The evaluation of malaria control intervention strategies mostly consists of identifying cases of clinical malaria and is crucial to promote better diagnosis for accurate measurement of the impact of the intervention. We sought out to define and quantify clinical malaria cases in children from three health districts in the Northern region of Cameroon. A cohort study of 6,195 children aged between 6 and 120 months was carried out during the raining season (July to October) between 2013 and 2014. Differential diagnosis of clinical malaria was performed using the parasite density and axillary temperature. At recruitment, patients with malaria-related symptoms (fever [axillary temperature ≥ 37.5°C], chills, severe malaise, headache, or vomiting) and a malaria positive blood smear were classified under clinical malaria group. The malaria attributable fraction was calculated using logistic regression models. Plasmodium falciparum was responsible for over 91% of infections. Children from Pitoa health district had the highest number of asymptomatic infections (45.60%) compared to those from Garoua and Mayo Oulo. The most suitable cut-off for the association between parasite densities and fever was found among children less than 24 months. Overall, parasite densities that ranged above 3,200 parasites per μl of blood could be used to define the malaria attributable fever cases. In groups of children aged between 24 and 59 months and 60 and 94 months, the optimum cut-off parasite density was 6,400 parasites per μl of blood, while children aged between 95 and 120 months had a cut-off of 800 parasites per μl of blood. In the same ecoepidemiological zone, clinical malaria case definitions are influenced by age and location (health district) and this could be considered when evaluating malaria intervention strategies in endemic areas.
Collapse
|
33
|
Burkot TR, Bugoro H, Apairamo A, Cooper RD, Echeverry DF, Odabasi D, Beebe NW, Makuru V, Xiao H, Davidson JR, Deason NA, Reuben H, Kazura JW, Collins FH, Lobo NF, Russell TL. Spatial-temporal heterogeneity in malaria receptivity is best estimated by vector biting rates in areas nearing elimination. Parasit Vectors 2018; 11:606. [PMID: 30482239 PMCID: PMC6260740 DOI: 10.1186/s13071-018-3201-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 11/14/2018] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Decisions on when vector control can be withdrawn after malaria is eliminated depend on the receptivity or potential of an area to support vector populations. To guide malaria control and elimination programmes, the potential of biting rates, sporozoite rates, entomological inoculation rates and parity rates to estimate malaria receptivity and transmission were compared within and among geographically localised villages of active transmission in the Western Province of the Solomon Islands. RESULTS Malaria transmission and transmission potential was heterogeneous in both time and space both among and within villages as defined by anopheline species composition and biting densities. Biting rates during the peak biting period (from 18:00 to 00:00 h) of the primary vector, Anopheles farauti, ranged from less than 0.3 bites per person per half night in low receptivity villages to 26 bites per person in highly receptive villages. Within villages, sites with high anopheline biting rates were significantly clustered. Sporozoite rates provided evidence for continued transmission of Plasmodium falciparum, P. vivax and P. ovale by An. farauti and for incriminating An. hinesorum, as a minor vector, but were unreliable as indicators of transmission intensity. CONCLUSIONS In the low transmission area studied, sporozoite, entomological inoculation and parity rates could not be measured with the precision required to provide guidance to malaria programmes. Receptivity and potential transmission risk may be most reliably estimated by the vector biting rate. These results support the meaningful design of operational research programmes to ensure that resources are focused on providing information that can be utilised by malaria control programmes to best understand both transmission, transmission risk and receptivity across different areas.
Collapse
Affiliation(s)
- Thomas R. Burkot
- James Cook University, Australian Institute of Tropical Health and Medicine, Cairns, QLD 4870 Australia
| | - Hugo Bugoro
- National Vector Borne Disease Control Programme, Ministry of Health and Medical Services, Honiara, Solomon Islands
- Research Department, Solomon Islands National University, Honiara, Solomon Islands
| | - Allan Apairamo
- National Vector Borne Disease Control Programme, Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Robert D. Cooper
- Australian Army Malaria Institute, Gallipoli Barracks, Enoggera, 4052 Australia
| | - Diego F. Echeverry
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Danyal Odabasi
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Nigel W. Beebe
- University of Queensland, School of Biological Sciences, QLD, St. Lucia, 4068 Australia
- CSIRO, Dutton Park, Brisbane, QLD 4102 Australia
| | - Victoria Makuru
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Honglin Xiao
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Jenna R. Davidson
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Nicholas A. Deason
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Hedrick Reuben
- Western Province Malaria Control, Gizo, Western Province Solomon Islands
| | - James W. Kazura
- Center for Global Health & Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106–4983 USA
| | - Frank H. Collins
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Neil F. Lobo
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556 USA
| | - Tanya L. Russell
- James Cook University, Australian Institute of Tropical Health and Medicine, Cairns, QLD 4870 Australia
| |
Collapse
|
34
|
Routledge I, Chevéz JER, Cucunubá ZM, Rodriguez MG, Guinovart C, Gustafson KB, Schneider K, Walker PGT, Ghani AC, Bhatt S. Estimating spatiotemporally varying malaria reproduction numbers in a near elimination setting. Nat Commun 2018; 9:2476. [PMID: 29946060 PMCID: PMC6018772 DOI: 10.1038/s41467-018-04577-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 05/02/2018] [Indexed: 01/08/2023] Open
Abstract
In 2016 the World Health Organization identified 21 countries that could eliminate malaria by 2020. Monitoring progress towards this goal requires tracking ongoing transmission. Here we develop methods that estimate individual reproduction numbers and their variation through time and space. Individual reproduction numbers, Rc, describe the state of transmission at a point in time and differ from mean reproduction numbers, which are averages of the number of people infected by a typical case. We assess elimination progress in El Salvador using data for confirmed cases of malaria from 2010 to 2016. Our results demonstrate that whilst the average number of secondary malaria cases was below one (0.61, 95% CI 0.55–0.65), individual reproduction numbers often exceeded one. We estimate a decline in Rc between 2010 and 2016. However we also show that if importation is maintained at the same rate, the country may not achieve malaria elimination by 2020. Twenty one countries have been identified for malaria elimination by 2020 and their progress needs to be constantly evaluated. Here, the authors present a method that estimates individual reproduction numbers and their variation through time and space and use it to monitor elimination success in El Salvador between 2010 and 2016.
Collapse
Affiliation(s)
- Isobel Routledge
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK.
| | | | - Zulma M Cucunubá
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK
| | | | | | | | | | - Patrick G T Walker
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK
| | - Azra C Ghani
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK
| | - Samir Bhatt
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, UK
| |
Collapse
|
35
|
A qualitative study of community perception and acceptance of biological larviciding for malaria mosquito control in rural Burkina Faso. BMC Public Health 2018; 18:399. [PMID: 29566754 PMCID: PMC5865284 DOI: 10.1186/s12889-018-5299-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 03/12/2018] [Indexed: 12/02/2022] Open
Abstract
Background Vector and malaria parasite’s rising resistance against pyrethroid-impregnated bed nets and antimalarial drugs highlight the need for additional control measures. Larviciding against malaria vectors is experiencing a renaissance with the availability of environmentally friendly and target species-specific larvicides. In this study, we analyse the perception and acceptability of spraying surface water collections with the biological larvicide Bacillus thuringiensis israelensis in a single health district in Burkina Faso. Methods A total of 12 focus group discussions and 12 key informant interviews were performed in 10 rural villages provided with coverage of various larvicide treatments (all breeding sites treated, the most productive breeding sites treated, and untreated control). Results Respondents’ knowledge about the major risk factors for malaria transmission was generally good. Most interviewees stated they performed personal protective measures against vector mosquitoes including the use of bed nets and sometimes mosquito coils and traditional repellents. The acceptance of larviciding in and around the villages was high and the majority of respondents reported a relief in mosquito nuisance and malarial episodes. There was high interest in the project and demand for future continuation. Conclusion This study showed that larviciding interventions received positive resonance from the population. People showed a willingness to be involved and financially support the program. The positive environment with high acceptance for larviciding programs would facilitate routine implementation. An essential factor for the future success of such programs would be inclusion in regional or national malaria control guidelines. Electronic supplementary material The online version of this article (10.1186/s12889-018-5299-7) contains supplementary material, which is available to authorized users.
Collapse
|
36
|
Tassi Yunga S, Kayatani AK, Fogako J, Leke RJI, Leke RGF, Taylor DW. Timing of the human prenatal antibody response to Plasmodium falciparum antigens. PLoS One 2017; 12:e0184571. [PMID: 28950009 PMCID: PMC5614534 DOI: 10.1371/journal.pone.0184571] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 08/25/2017] [Indexed: 12/27/2022] Open
Abstract
Plasmodium falciparum (Pf)-specific T- and B-cell responses may be present at birth; however, when during fetal development antibodies are produced is unknown. Accordingly, cord blood samples from 232 preterm (20–37 weeks of gestation) and 450 term (≥37 weeks) babies were screened for IgM to Pf blood-stage antigens MSP1, MSP2, AMA1, EBA175 and RESA. Overall, 25% [95% CI = 22–28%] of the 682 newborns were positive for IgM to ≥1 Pf antigens with the earliest response occurring at 22 weeks. Interestingly, the odds of being positive for cord blood Pf IgM decreased with gestational age (adjusted OR [95% CI] at 20–31 weeks = 2.55 [1.14–5.85] and at 32–36 weeks = 1.97 [0.92–4.29], with ≥37 weeks as reference); however, preterm and term newborns had similar levels of Pf IgM and recognized a comparable breadth of antigens. Having cord blood Pf IgM was associated with placental malaria (adjusted OR [95% CI] = 2.37 [1.25–4.54]). To determine if in utero exposure occurred via transplacental transfer of Pf-IgG immune complexes (IC), IC containing MSP1 and MSP2 were measured in plasma of 242 mother-newborn pairs. Among newborns of IC-positive mothers (77/242), the proportion of cord samples with Pf IC increased with gestational age but was not associated with Pf IgM, suggesting that fetal B cells early in gestation had not been primed by IC. Finally, when cord mononuclear cells from 64 term newborns were cultured in vitro, only 11% (7/64) of supernatants had Pf IgM; whereas, 95% (61/64) contained secreted Pf IgG. These data suggest fetal B cells are capable of making Pf-specific IgM from early in the second trimester and undergo isotype switching to IgG towards term.
Collapse
Affiliation(s)
- Samuel Tassi Yunga
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Alexander K. Kayatani
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Josephine Fogako
- The Biotechnology Center, University of Yaoundé 1, Yaoundé, Cameroon
| | - Robert J. I. Leke
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon
| | - Rose G. F. Leke
- The Biotechnology Center, University of Yaoundé 1, Yaoundé, Cameroon
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon
| | - Diane W. Taylor
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- * E-mail:
| |
Collapse
|
37
|
McCann RS, van den Berg H, Diggle PJ, van Vugt M, Terlouw DJ, Phiri KS, Di Pasquale A, Maire N, Gowelo S, Mburu MM, Kabaghe AN, Mzilahowa T, Chipeta MG, Takken W. Assessment of the effect of larval source management and house improvement on malaria transmission when added to standard malaria control strategies in southern Malawi: study protocol for a cluster-randomised controlled trial. BMC Infect Dis 2017; 17:639. [PMID: 28938876 PMCID: PMC5610449 DOI: 10.1186/s12879-017-2749-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 09/19/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Due to outdoor and residual transmission and insecticide resistance, long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) will be insufficient as stand-alone malaria vector control interventions in many settings as programmes shift toward malaria elimination. Combining additional vector control interventions as part of an integrated strategy would potentially overcome these challenges. Larval source management (LSM) and structural house improvements (HI) are appealing as additional components of an integrated vector management plan because of their long histories of use, evidence on effectiveness in appropriate settings, and unique modes of action compared to LLINs and IRS. Implementation of LSM and HI through a community-based approach could provide a path for rolling-out these interventions sustainably and on a large scale. METHODS/DESIGN We will implement community-based LSM and HI, as additional interventions to the current national malaria control strategies, using a randomised block, 2 × 2 factorial, cluster-randomised design in rural, southern Malawi. These interventions will be continued for two years. The trial catchment area covers about 25,000 people living in 65 villages. Community participation is encouraged by training community volunteers as health animators, and supporting the organisation of village-level committees in collaboration with The Hunger Project, a non-governmental organisation. Household-level cross-sectional surveys, including parasitological and entomological sampling, will be conducted on a rolling, 2-monthly schedule to measure outcomes over two years (2016 to 2018). Coverage of LSM and HI will also be assessed throughout the trial area. DISCUSSION Combining LSM and/or HI together with the interventions currently implemented by the Malawi National Malaria Control Programme is anticipated to reduce malaria transmission below the level reached by current interventions alone. Implementation of LSM and HI through a community-based approach provides an opportunity for optimum adaptation to the local ecological and social setting, and enhances the potential for sustainability. TRIAL REGISTRATION Registered with The Pan African Clinical Trials Registry on 3 March 2016, trial number PACTR201604001501493.
Collapse
Affiliation(s)
- Robert S McCann
- Wageningen University and Research, Wageningen, The Netherlands. .,College of Medicine, University of Malawi, Blantyre, Malawi. .,Laboratory of Entomology, Wageningen University and Research, PO Box 16, 6700, AA, Wageningen, The Netherlands.
| | | | | | - Michèle van Vugt
- Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Dianne J Terlouw
- Liverpool School of Tropical Medicine, Liverpool, UK.,Malawi-Liverpool Wellcome Trust, Blantyre, Malawi
| | - Kamija S Phiri
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Aurelio Di Pasquale
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Nicolas Maire
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Steven Gowelo
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Monicah M Mburu
- Wageningen University and Research, Wageningen, The Netherlands.,College of Medicine, University of Malawi, Blantyre, Malawi
| | - Alinune N Kabaghe
- College of Medicine, University of Malawi, Blantyre, Malawi.,Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Michael G Chipeta
- College of Medicine, University of Malawi, Blantyre, Malawi.,Lancaster University, Lancaster, UK.,Malawi-Liverpool Wellcome Trust, Blantyre, Malawi
| | - Willem Takken
- Wageningen University and Research, Wageningen, The Netherlands
| |
Collapse
|
38
|
Ya-Umphan P, Cerqueira D, Parker DM, Cottrell G, Poinsignon A, Remoue F, Brengues C, Chareonviriyaphap T, Nosten F, Corbel V. Use of an Anopheles Salivary Biomarker to Assess Malaria Transmission Risk Along the Thailand-Myanmar Border. J Infect Dis 2017; 215:396-404. [PMID: 27932615 PMCID: PMC5853934 DOI: 10.1093/infdis/jiw543] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/15/2016] [Indexed: 11/13/2022] Open
Abstract
Background The modalities of malaria transmission along the Thailand-Myanmar border are poorly understood. Here we address the relevance of using a specific Anopheles salivary biomarker to measure the risk among humans of exposure to Anopheles bites. Methods Serologic surveys were conducted from May 2013 to December 2014 in 4 sentinel villages. More than 9400 blood specimens were collected in filter papers from all inhabitants at baseline and then every 3 months thereafter, for up to 18 months, for analysis by enzyme-linked immunosorbent assay. The relationship between the intensity of the human antibody response and entomological indicators of transmission (human biting rates and entomological inoculation rates [EIRs]) was studied using a multivariate 3-level mixed model analysis. Heat maps for human immunoglobulin G (IgG) responses for each village and survey time point were created using QGIS 2.4. Results The levels of IgG response among participants varied significantly according to village, season, and age (P<.001) and were positively associated with the abundance of total Anopheles species and primary malaria vectors and the EIR (P<.001). Spatial clusters of high-IgG responders were identified across space and time within study villages. Conclusions The gSG6-P1 biomarker has great potential to address the risk of transmission along the Thailand-Myanmar border and represents a promising tool to guide malaria interventions.
Collapse
Affiliation(s)
- Phubeth Ya-Umphan
- Institut de Recherche pour le Développement, Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Montpellier, and
- Department of Entomology, Faculty of Agriculture, and
| | - Dominique Cerqueira
- Department of Entomology, Faculty of Agriculture, and
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; and
| | - Daniel M Parker
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; and
| | - Gilles Cottrell
- Institut de Recherche pour le Développement, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Anne Poinsignon
- Institut de Recherche pour le Développement, Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Montpellier, and
| | - Franck Remoue
- Institut de Recherche pour le Développement, Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Montpellier, and
| | - Cecile Brengues
- Institut de Recherche pour le Développement, Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Montpellier, and
| | - Theeraphap Chareonviriyaphap
- Department of Entomology, Faculty of Agriculture, and
- Center for Advanced Studies for Agriculture and Food, Kasetsart University Institute for Advanced Studies, Kasetsart University, Bangkok, and
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand; and
- Nuffield Department of Medicine, Centre for Tropical Medicine, University of Oxford, United Kingdom
| | - Vincent Corbel
- Institut de Recherche pour le Développement, Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, Montpellier, and
- Institut de Recherche pour le Développement, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| |
Collapse
|
39
|
Vezenegho SB, Adde A, Pommier de Santi V, Issaly J, Carinci R, Gaborit P, Dusfour I, Girod R, Briolant S. High malaria transmission in a forested malaria focus in French Guiana: How can exophagic Anopheles darlingi thwart vector control and prevention measures? Mem Inst Oswaldo Cruz 2017; 111:561-9. [PMID: 27653361 PMCID: PMC5027866 DOI: 10.1590/0074-02760160150] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Accepted: 07/12/2016] [Indexed: 12/01/2022] Open
Abstract
In French Guiana, malaria vector control and prevention relies on indoor residual
spraying and distribution of long lasting insecticidal nets. These measures are based
on solid epidemiological evidence but reveal a poor understanding of the vector. The
current study investigated the behaviour of both vectors and humans in relation to
the ongoing prevention strategies. In 2012 and 2013, Anopheles
mosquitoes were sampled outdoors at different seasons and in various time slots. The
collected mosquitoes were identified and screened for Plasmodium
infection. Data on human behaviour and malaria episodes were obtained from an
interview. A total of 3,135 Anopheles mosquitoes were collected, of
which Anopheles darlingi was the predominant species (96.2%). For
the December 2012-February 2013 period, the Plasmodium vivax
infection rate for An. darlingi was 7.8%, and the entomological
inoculation rate was 35.7 infective bites per person per three-month span. In spite
of high bednet usage (95.7%) in 2012 and 2013, 52.2% and 37.0% of the participants,
respectively, had at least one malaria episode. An. darlingi
displayed heterogeneous biting behaviour that peaked between 20:30 and 22:30;
however, 27.6% of the inhabitants were not yet protected by bednets by 21:30. The use
of additional individual and collective protective measures is required to limit
exposure to infective mosquito bites and reduce vector densities.
Collapse
Affiliation(s)
- Samuel B Vezenegho
- Institut Pasteur de la Guyane, Unité d'Entomologie Médicale, Cayenne, Guyane, France
| | - Antoine Adde
- Institut Pasteur de la Guyane, Unité d'Entomologie Médicale, Cayenne, Guyane, France
| | - Vincent Pommier de Santi
- Centre d'Epidémiologie et de Santé Publique des Armées, Marseille, France.,Direction Interarmées du Service de Santé en Guyane, Cayenne, Guyane, France
| | - Jean Issaly
- Institut Pasteur de la Guyane, Unité d'Entomologie Médicale, Cayenne, Guyane, France
| | - Romuald Carinci
- Institut Pasteur de la Guyane, Unité d'Entomologie Médicale, Cayenne, Guyane, France
| | - Pascal Gaborit
- Institut Pasteur de la Guyane, Unité d'Entomologie Médicale, Cayenne, Guyane, France
| | - Isabelle Dusfour
- Institut Pasteur de la Guyane, Unité d'Entomologie Médicale, Cayenne, Guyane, France
| | - Romain Girod
- Institut Pasteur de la Guyane, Unité d'Entomologie Médicale, Cayenne, Guyane, France
| | - Sébastien Briolant
- Institut Pasteur de la Guyane, Unité d'Entomologie Médicale, Cayenne, Guyane, France.,Direction Interarmées du Service de Santé en Guyane, Cayenne, Guyane, France.,Institut de Recherche Biomédicale des Armées, Département des Maladies Infectieuses, Unité de Parasitologie et d'Entomologie, Brétigny sur Orge, France.,Aix Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Marseille, France
| |
Collapse
|
40
|
Baffour-Awuah S, Annan AA, Maiga-Ascofare O, Dieudonné SD, Adjei-Kusi P, Owusu-Dabo E, Obiri-Danso K. Insecticide resistance in malaria vectors in Kumasi, Ghana. Parasit Vectors 2016; 9:633. [PMID: 27927238 PMCID: PMC5142350 DOI: 10.1186/s13071-016-1923-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 12/01/2016] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND There have been recent reports of surge in resistance to insecticides in pocketed areas in Ghana necessitating the need for information about local vector populations and their resistance to the insecticides approved by the World Health Organization (WHO). We therefore studied a population of malaria vectors from Kumasi in the Ashanti Region of Ghana and their resistance to currently used insecticides. We conducted susceptibility tests to the four major classes of insecticides by collecting larvae of anopheline mosquitoes from several communities in the region. Surviving adults from these larvae were then subjected to the WHO-approved susceptibility tests and characterization of knockdown resistance and acetylcholinesterase mutant genes. RESULTS Out of 619 Anopheles specimens sampled, 537 (87%) were identified as Anopheles gambiae (sensu stricto), which was also the species with the lowest knockdown resistance mutant gene, 61% (P = 0.017). Knockdown resistance mutant gene was as high as 91% in An. coluzzii. Mosquitoes collected showed susceptibility ranging from 98-100% to organophosphates, 38-56% to carbamates and 15-47% and 38-46% to pyrethroids and organochlorides, respectively. The knockdown resistance mutation frequency of Anopheles gambiae (sensu lato) mosquitoes that were exposed to both pyrethroids and organochlorides was 404 (65%). Acetylcholinesterase mutant gene was not found in this population of vectors. CONCLUSION Our study shows that pyrethroids have the highest level of resistance in the population of mosquito vectors studied probably due to their frequent use, especially in impregnation of insecticide-treated nets and in insecticides used to control pests on irrigated vegetable farms. We recommend studies to monitor trends in the use of all insecticides and of pyrethroids in particular.
Collapse
Affiliation(s)
- Sandra Baffour-Awuah
- Kumasi Centre for Collaborative Research (KCCR), College of Health Sciences, Kumasi, Ghana
- Department of Theoretical and Applied Biology, College of Science, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Augustina A. Annan
- Kumasi Centre for Collaborative Research (KCCR), College of Health Sciences, Kumasi, Ghana
- Department of Theoretical and Applied Biology, College of Science, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| | - Oumou Maiga-Ascofare
- Kumasi Centre for Collaborative Research (KCCR), College of Health Sciences, Kumasi, Ghana
- Bernhard-Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | | | - Priscilla Adjei-Kusi
- Kumasi Centre for Collaborative Research (KCCR), College of Health Sciences, Kumasi, Ghana
| | - Ellis Owusu-Dabo
- Kumasi Centre for Collaborative Research (KCCR), College of Health Sciences, Kumasi, Ghana
- School of Public Health, College of Health Sciences, KNUST, Kumasi, Ghana
| | - Kwasi Obiri-Danso
- Department of Theoretical and Applied Biology, College of Science, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana
| |
Collapse
|
41
|
Fontana MF, Baccarella A, Craft JF, Boyle MJ, McIntyre TI, Wood MD, Thorn KS, Anidi C, Bayat A, Chung MR, Hamburger R, Kim CY, Pearman E, Pham J, Tang JJ, Boon L, Kamya MR, Dorsey G, Feeney ME, Kim CC. A Novel Model of Asymptomatic Plasmodium Parasitemia That Recapitulates Elements of the Human Immune Response to Chronic Infection. PLoS One 2016; 11:e0162132. [PMID: 27583554 PMCID: PMC5008831 DOI: 10.1371/journal.pone.0162132] [Citation(s) in RCA: 12] [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: 06/16/2016] [Accepted: 08/17/2016] [Indexed: 11/18/2022] Open
Abstract
In humans, immunity to Plasmodium sp. generally takes the form of protection from symptomatic malaria (i.e., 'clinical immunity') rather than infection ('sterilizing immunity'). In contrast, mice infected with Plasmodium develop sterilizing immunity, hindering progress in understanding the mechanistic basis of clinical immunity. Here we present a novel model in which mice persistently infected with P. chabaudi exhibit limited clinical symptoms despite sustaining patent parasite burdens for many months. Characterization of immune responses in persistently infected mice revealed development of CD4+ T cell exhaustion, increased production of IL-10, and expansion of B cells with an atypical surface phenotype. Additionally, persistently infected mice displayed a dramatic increase in circulating nonclassical monocytes, a phenomenon that we also observed in humans with both chronic Plasmodium exposure and asymptomatic infection. Following pharmacological clearance of infection, previously persistently infected mice could not control a secondary challenge, indicating that persistent infection disrupts the sterilizing immunity that typically develops in mouse models of acute infection. This study establishes an animal model of asymptomatic, persistent Plasmodium infection that recapitulates several central aspects of the immune response in chronically exposed humans. As such, it provides a novel tool for dissection of immune responses that may prevent development of sterilizing immunity and limit pathology during infection.
Collapse
Affiliation(s)
- Mary F. Fontana
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Alyssa Baccarella
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Joshua F. Craft
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Michelle J. Boyle
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
- The Burnet Institute, Center for Biomedical Research, Melbourne, Australia
| | - Tara I. McIntyre
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Matthew D. Wood
- Department of Pathology, Division of Neuropathology, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Kurt S. Thorn
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, 94158, United States of America
| | - Chioma Anidi
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Aqieda Bayat
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Me Ree Chung
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Rebecca Hamburger
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Chris Y. Kim
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Emily Pearman
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Jennifer Pham
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Jia J. Tang
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Louis Boon
- EPIRUS Biopharmaceuticals, Utrecht, Netherlands BV
| | - Moses R. Kamya
- School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
| | - Grant Dorsey
- Division of Infectious Diseases, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Margaret E. Feeney
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
- Division of Pediatric Infectious Diseases and Global Health, Department of Pediatrics, University of California San Francisco, San Francisco, California, 94143, United States of America
| | - Charles C. Kim
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, 94143, United States of America
- * E-mail:
| |
Collapse
|
42
|
Reiner RC, Guerra C, Donnelly MJ, Bousema T, Drakeley C, Smith DL. Estimating malaria transmission from humans to mosquitoes in a noisy landscape. J R Soc Interface 2016; 12:20150478. [PMID: 26400195 PMCID: PMC4614487 DOI: 10.1098/rsif.2015.0478] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A basic quantitative understanding of malaria transmission requires measuring the probability a mosquito becomes infected after feeding on a human. Parasite prevalence in mosquitoes is highly age-dependent, and the unknown age-structure of fluctuating mosquito populations impedes estimation. Here, we simulate mosquito infection dynamics, where mosquito recruitment is modelled seasonally with fractional Brownian noise, and we develop methods for estimating mosquito infection rates. We find that noise introduces bias, but the magnitude of the bias depends on the ‘colour' of the noise. Some of these problems can be overcome by increasing the sampling frequency, but estimates of transmission rates (and estimated reductions in transmission) are most accurate and precise if they combine parity, oocyst rates and sporozoite rates. These studies provide a basis for evaluating the adequacy of various entomological sampling procedures for measuring malaria parasite transmission from humans to mosquitoes and for evaluating the direct transmission-blocking effects of a vaccine.
Collapse
Affiliation(s)
- Robert C Reiner
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA Department of Entomology, University of California, Davis, CA, USA Department of Epidemiology and Biostatistics, Indiana University, Bloomington, IN, USA
| | - Carlos Guerra
- Center for Disease Dynamics, Economics and Policy, Washington, DC, USA
| | - Martin J Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK Malaria Programme, Wellcome Trust Sanger Institute, Cambridge, UK
| | - Teun Bousema
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - David L Smith
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA Sanaria Institute for Global Health and Tropical Medicine, Rockville, MD, USA Department of Zoology, University of Oxford, Oxford, UK Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA
| |
Collapse
|
43
|
Dambach P, Schleicher M, Stahl HC, Traoré I, Becker N, Kaiser A, Sié A, Sauerborn R. Routine implementation costs of larviciding with Bacillus thuringiensis israelensis against malaria vectors in a district in rural Burkina Faso. Malar J 2016; 15:380. [PMID: 27449023 PMCID: PMC4957841 DOI: 10.1186/s12936-016-1438-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/12/2016] [Indexed: 11/25/2022] Open
Abstract
Background The key tools in malaria control are early diagnosis and treatment of cases as well as vector control. Current strategies for malaria vector control in sub-Saharan Africa are largely based on long-lasting insecticide-treated nets (LLINs) and to a much smaller extent on indoor residual spraying (IRS). An additional tool in the fight against malaria vectors, larval source management (LSM), has not been used in sub-Saharan Africa on a wider scale since the abandonment of environmental spraying of DDT. Increasing concerns about limitations of LLINs and IRS and encouraging results from large larvicide-based LSM trials make a strong case for using biological larviciding as a complementary tool to existing control measures. Arguments that are often quoted against such a combined approach are the alleged high implementation costs of LSM. This study makes the first step to test this argument. The implementation costs of larval source management based on Bacillus thuringiensis israelensis (Bti) (strain AM65-52) spraying under different implementation scenarios were analysed in a rural health district in Burkina Faso. Methods The analysis draws on detailed cost data gathered during a large-scale LSM intervention between 2013 and 2015. All 127 villages in the study setup were assigned to two treatment arms and one control group. Treatment either implied exhaustive spraying of all available water collections or targeted spraying of the 50 % most productive larval sources via remote-sensing derived and entomologically validated risk maps. Based on the cost reports from both intervention arms, the per capita programme costs were calculated under the assumption of covering the whole district with either intervention scenario. Cost calculations have been generalized by providing an adaptable cost formula. In addition, this study assesses the sensitivity of per capita programme costs with respect to changes in the underlying cost components. Results The average annual per capita costs of exhaustive larviciding with Bti during the main malaria transmission period (June–October) in the Nouna health district were calculated to be US$ 1.05. When targeted spraying of the 50 % most productive larval sources is used instead, average annual per capita costs decrease by 27 % to US$ 0.77. Additionally, a high sensitivity of per capita programme costs against changes in total surface of potential larval sources and the number of spraying repetitions was found. Discussion The per capita costs for larval source management interventions with Bti are roughly a third of the annual per capita expenditures for anti-malarial drugs and those for LLINs in Burkina Faso which are US$ 3.80 and 3.00, respectively. The average LSM costs compare to those of IRS and LLINs for sub-Saharan Africa. The authors argue that in such a setting LSM based on Bti spraying is within the range of affordable anti-malarial strategies and, consequently, should deserve more attention in practice. Future research includes a cost-benefit calculation, based on entomological and epidemiological data collected during the research project. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1438-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Peter Dambach
- Institute of Public Health, University of Heidelberg, Heidelberg, Germany.
| | | | | | - Issouf Traoré
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | - Norbert Becker
- German Mosquito Control Association (KABS), Speyer, Germany.,Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Achim Kaiser
- German Mosquito Control Association (KABS), Speyer, Germany
| | - Ali Sié
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | - Rainer Sauerborn
- Institute of Public Health, University of Heidelberg, Heidelberg, Germany
| |
Collapse
|
44
|
Al-Eryani SMA, Kelly-Hope L, Harbach RE, Briscoe AG, Barnish G, Azazy A, McCall PJ. Entomological aspects and the role of human behaviour in malaria transmission in a highland region of the Republic of Yemen. Malar J 2016; 15:130. [PMID: 26932794 PMCID: PMC4774125 DOI: 10.1186/s12936-016-1179-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 02/17/2016] [Indexed: 11/25/2022] Open
Abstract
Background The Republic of Yemen has the highest incidence of malaria in the Arabian Peninsula, yet little is known of its vectors or transmission dynamics. Methods A 24-month study of the vectors and related epidemiological aspects of malaria transmission was conducted in two villages in the Taiz region in 2004–2005. Results Cross-sectional blood film surveys recorded an overall malaria infection rate of 15.3 % (250/1638), with highest rates exceeding 30 % in one village in May and December 2005. With one exception, Plasmodium malariae, all infections were P.falciparum. Seven Anopheles species were identified among 3407 anophelines collected indoors using light traps (LT) and pyrethrum knockdown catches (PKD): Anopheles arabiensis (86.9 %), An. sergentii (9 %), An. azaniae, An. dthali, An. pretoriensis, An. coustani and An. algeriensis. Sequences for the standard barcode region of the mitochondrial COI gene confirmed the presence of two morphological forms of An. azaniae, the typical form and a previously unrecognized form not immediately identifiable as An. azaniae. ELISA detected Plasmodium sporozoites in 0.9 % of 2921 An. arabiensis (23 P. falciparum, two P. vivax) confirming this species as the primary malaria vector in Yemen. Plasmodium falciparum sporozoites were detected in An. sergentii (2/295) and a single female of An. algeriensis, incriminating both species as malaria vectors for the first time in Yemen. A vector in both wet and dry seasons, An. arabiensis was predominantly anthropophilic (human blood index = 0.86) with an entomological inoculation rate of 1.58 infective bites/person/year. Anopheles sergentii fed on cattle (67.3 %) and humans (48.3; 20.7 % mixed both species), but only 14.7 % were found in PKDs, indicating predominantly exophilic behaviour. A GIS analysis of geographic and socio-economic parameters revealed that An. arabiensis were significantly higher (P < 0.001) in houses with televisions, most likely due to the popular evening habit of viewing television collectively in houses with open doors and windows. Conclusions The predominantly indoor human biting vectors recorded in this study could be targeted effectively with LLINs, indoor residual spraying and/or insecticide-treated window/door curtains reinforced by education to instil a perception that effective and affordable malaria prevention is achievable. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1179-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Samira M A Al-Eryani
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK. .,Department of Medical Parasitology, Faculty of Medicine and Health Sciences, University of Yemen, Sana'a, Yemen.
| | - Louise Kelly-Hope
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK.
| | - Ralph E Harbach
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, UK.
| | - Andrew G Briscoe
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, UK.
| | - Guy Barnish
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK.
| | - Ahmed Azazy
- Department of Medical Parasitology, Faculty of Medicine and Health Sciences, University of Yemen, Sana'a, Yemen.
| | - Philip J McCall
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK.
| |
Collapse
|
45
|
Yman V, White MT, Rono J, Arcà B, Osier FH, Troye-Blomberg M, Boström S, Ronca R, Rooth I, Färnert A. Antibody acquisition models: A new tool for serological surveillance of malaria transmission intensity. Sci Rep 2016; 6:19472. [PMID: 26846726 PMCID: PMC4984902 DOI: 10.1038/srep19472] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 12/09/2015] [Indexed: 11/13/2022] Open
Abstract
Serology has become an increasingly important tool for the surveillance of a wide range of infectious diseases. It has been particularly useful to monitor malaria transmission in elimination settings where existing metrics such as parasite prevalence and incidence of clinical cases are less sensitive. Seroconversion rates, based on antibody prevalence to Plasmodium falciparum asexual blood-stage antigens, provide estimates of transmission intensity that correlate with entomological inoculation rates but lack precision in settings where seroprevalence is still high. Here we present a new and widely applicable method, based on cross-sectional data on individual antibody levels. We evaluate its use as a sero-surveillance tool in a Tanzanian setting with declining malaria prevalence. We find that the newly developed mathematical models produce more precise estimates of transmission patterns, are robust in high transmission settings and when sample sizes are small, and provide a powerful tool for serological evaluation of malaria transmission intensity.
Collapse
Affiliation(s)
- Victor Yman
- Unit of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Michael T White
- MRC Centre for Outbreak Analysis &Modelling, Department of Infectious Disease Epidemiology, Imperial College, London, United Kingdom
| | - Josea Rono
- Unit of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.,KEMRI-Wellcome Trust Research Programme, Centre for Geographical Medicine Research-Coast, Kilifi, Kenya
| | - Bruno Arcà
- Department of Public Health and Infectious Diseases, Parasitology Section, Sapienza University of Rome, Italy
| | - Faith H Osier
- KEMRI-Wellcome Trust Research Programme, Centre for Geographical Medicine Research-Coast, Kilifi, Kenya
| | - Marita Troye-Blomberg
- Department of Molecular Biosciences, the Wenner-Gren Institute, Stockholm University, Sweden
| | - Stéphanie Boström
- Department of Molecular Biosciences, the Wenner-Gren Institute, Stockholm University, Sweden
| | - Raffaele Ronca
- Department of Biology, Federico II University, Naples, Italy
| | | | - Anna Färnert
- Unit of Infectious Diseases, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
46
|
Ferrari G, Ntuku HM, Schmidlin S, Diboulo E, Tshefu AK, Lengeler C. A malaria risk map of Kinshasa, Democratic Republic of Congo. Malar J 2016; 15:27. [PMID: 26762532 PMCID: PMC4712518 DOI: 10.1186/s12936-015-1074-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 12/23/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Kinshasa, malaria remains a major public health problem but its spatial epidemiology has not been assessed for decades now. The city's growth and transformation, as well as recent control measures, call for an update. To identify highly exposed communities and areas where control measures are less critically needed, detailed risk maps are required to target control and optimize resource allocation. METHODS In 2009 (end of the dry season) and 2011 (end of the rainy season), two cross-sectional surveys were conducted in Kinshasa to determine malaria prevalence, anaemia, history of fever, bed net ownership and use among children 6-59 months. Geo-referenced data for key parameters were mapped at the level of the health area (HA) by means of a geographic information system (GIS). RESULTS Among 7517 children aged 6-59 months from 33 health zones (HZs), 6661 (3319 in 2009 and 3342 in 2011) were tested for both malaria (by Rapid Diagnostic Tests) and anaemia, and 856 (845 in 2009 and 11 in 2011) were tested for anaemia only. Fifteen HZs were sampled in 2009, 25 in 2011, with seven HZs sampled in both surveys. Mean prevalence for malaria and anaemia was 6.4% (5.6-7.4) and 65.1% (63.7-66.6) in 2009, and 17.0% (15.7-18.3) and 64.2% (62.6-65.9) in 2011. In two HZs sampled in both surveys, malaria prevalence was 14.1 % and 26.8% in Selembao (peri-urban), in the 2009 dry season and 2011 rainy season respectively, and it was 1.0 % and 0.8% in Ngiri Ngiri (urban). History of fever during the preceding two weeks was 13.2% (12.5-14.3) and 22.3% (20.8-23.4) in 2009 and 2011. Household ownership of at least one insecticide-treated net (ITN) was 78.7% (77.4-80.0) and 65.0% (63.7-66.3) at both time points, while use was 57.7% (56.0-59.9) and 45.0% (43.6-46.8), respectively. CONCLUSIONS This study presents the first malaria risk map of Kinshasa, a mega city of roughly 10 million inhabitants and located in a highly endemic malaria zone. Prevalence of malaria, anaemia and reported fever was lower in urban areas, whereas low coverage of ITN and sub-optimal net use were frequent in peri-urban areas.
Collapse
Affiliation(s)
- Giovanfrancesco Ferrari
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Henry M Ntuku
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Kinshasa School of Public Health, Kinshasa, Democratic Republic of the Congo.
| | - Sandro Schmidlin
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Eric Diboulo
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Antoinette K Tshefu
- Kinshasa School of Public Health, Kinshasa, Democratic Republic of the Congo.
| | - Christian Lengeler
- Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| |
Collapse
|
47
|
Doucoure S, Drame PM. Salivary Biomarkers in the Control of Mosquito-Borne Diseases. INSECTS 2015; 6:961-76. [PMID: 26593952 PMCID: PMC4693181 DOI: 10.3390/insects6040961] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 06/15/2015] [Accepted: 09/14/2015] [Indexed: 11/26/2022]
Abstract
Vector control remains the most effective measure to prevent the transmission of mosquito-borne diseases. However, the classical entomo-parasitological methods used to evaluate the human exposure to mosquito bites and the effectiveness of control strategies are indirect, labor intensive, and lack sensitivity in low exposure/transmission areas. Therefore, they are limited in their accuracy and widespread use. Studying the human antibody response against the mosquito salivary proteins has provided new biomarkers for a direct and accurate evaluation of the human exposure to mosquito bites, at community and individual levels. In this review, we discuss the development, applications and limits of these biomarkers applied to Aedes- and Anopheles-borne diseases.
Collapse
Affiliation(s)
- Souleymane Doucoure
- Institut de Recherche pour le Développement, Unité de Recherche sur les Maladies Infectieuses Tropicales Emergentes (URMITE) UM63: CNRS7278-IRD 198-INSERM U1095 Campus IRD-UCAD, BP 1386, Dakar 18524, Sénégal.
| | - Papa Makhtar Drame
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
48
|
Parham PE, Waldock J, Christophides GK, Hemming D, Agusto F, Evans KJ, Fefferman N, Gaff H, Gumel A, LaDeau S, Lenhart S, Mickens RE, Naumova EN, Ostfeld RS, Ready PD, Thomas MB, Velasco-Hernandez J, Michael E. Climate, environmental and socio-economic change: weighing up the balance in vector-borne disease transmission. Philos Trans R Soc Lond B Biol Sci 2015; 370:rstb.2013.0551. [PMID: 25688012 DOI: 10.1098/rstb.2013.0551] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Arguably one of the most important effects of climate change is the potential impact on human health. While this is likely to take many forms, the implications for future transmission of vector-borne diseases (VBDs), given their ongoing contribution to global disease burden, are both extremely important and highly uncertain. In part, this is owing not only to data limitations and methodological challenges when integrating climate-driven VBD models and climate change projections, but also, perhaps most crucially, to the multitude of epidemiological, ecological and socio-economic factors that drive VBD transmission, and this complexity has generated considerable debate over the past 10-15 years. In this review, we seek to elucidate current knowledge around this topic, identify key themes and uncertainties, evaluate ongoing challenges and open research questions and, crucially, offer some solutions for the field. Although many of these challenges are ubiquitous across multiple VBDs, more specific issues also arise in different vector-pathogen systems.
Collapse
Affiliation(s)
- Paul E Parham
- Department of Public Health and Policy, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3GL, UK Grantham Institute for Climate Change, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, St Mary's Campus, London W2 1PG, UK
| | - Joanna Waldock
- The Cyprus Institute, Nicosia, Cyprus Imperial College London, London SW7 2AZ, UK
| | | | - Deborah Hemming
- Meteorological Office Hadley Centre, UK Meteorological Office, Fitzroy Road, Exeter, EX1 3PB, UK
| | - Folashade Agusto
- Department of Mathematics, Austin Peay State University, Clarksville, TN 37044, USA
| | - Katherine J Evans
- Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831, USA
| | - Nina Fefferman
- Department of Ecology, Evolution and Natural Resources, Rutgers University, New Brunswick, NJ 08901, USA
| | - Holly Gaff
- Department of Biological Sciences, Old Dominium University, Norfolk, VA 23529, USA
| | - Abba Gumel
- Simon A. Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University, Tempe, AZ 85287-1904, USA School of Mathematical and Natural Sciences, Arizona State University, Phoenix, AZ 85069-7100, USA
| | - Shannon LaDeau
- Cary Institute of Ecosystem Studies, PO Box AB, Millbrook, NY 12545-0129, USA
| | - Suzanne Lenhart
- Department of Mathematics, University of Tennessee, Knoxville, TN 37996-1300, USA
| | - Ronald E Mickens
- Department of Physics, Clark Atlanta University, PO Box 172, Atlanta, GA 30314, USA
| | - Elena N Naumova
- Department of Civil and Environmental Engineering, Tufts University School of Engineering, Medford, MA 02155, USA
| | - Richard S Ostfeld
- Cary Institute of Ecosystem Studies, PO Box AB, Millbrook, NY 12545-0129, USA
| | - Paul D Ready
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Matthew B Thomas
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA
| | - Jorge Velasco-Hernandez
- Universidad Nacional Autnoma de Mexico Institute of Mathematics Mexico City, Distrito Federal, Mexico
| | - Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556-0369, USA
| |
Collapse
|
49
|
Griffin JT, Ferguson NM, Ghani AC. Estimates of the changing age-burden of Plasmodium falciparum malaria disease in sub-Saharan Africa. Nat Commun 2015; 5:3136. [PMID: 24518518 PMCID: PMC3923296 DOI: 10.1038/ncomms4136] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 12/17/2013] [Indexed: 01/08/2023] Open
Abstract
Estimating the changing burden of malaria disease remains difficult owing to limitations in health reporting systems. Here, we use a transmission model incorporating acquisition and loss of immunity to capture age-specific patterns of disease at different transmission intensities. The model is fitted to age-stratified data from 23 sites in Africa, and we then produce maps and estimates of disease burden. We estimate that in 2010 there were 252 (95% credible interval: 171-353) million cases of malaria in sub-Saharan Africa that active case finding would detect. However, only 34% (12-86%) of these cases would be observed through passive case detection. We estimate that the proportion of all cases of clinical malaria that are in under-fives varies from above 60% at high transmission to below 20% at low transmission. The focus of some interventions towards young children may need to be reconsidered, and should be informed by the current local transmission intensity.
Collapse
Affiliation(s)
- Jamie T Griffin
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK
| | - Neil M Ferguson
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK
| | - Azra C Ghani
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London W2 1PG, UK
| |
Collapse
|
50
|
Hotspots of Malaria Transmission in the Peruvian Amazon: Rapid Assessment through a Parasitological and Serological Survey. PLoS One 2015; 10:e0137458. [PMID: 26356311 PMCID: PMC4565712 DOI: 10.1371/journal.pone.0137458] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/17/2015] [Indexed: 11/29/2022] Open
Abstract
Background With low and markedly seasonal malaria transmission, increasingly sensitive tools for better stratifying the risk of infection and targeting control interventions are needed. A cross-sectional survey to characterize the current malaria transmission patterns, identify hotspots, and detect recent changes using parasitological and serological measures was conducted in three sites of the Peruvian Amazon. Material and Methods After full census of the study population, 651 participants were interviewed, clinically examined and had a blood sample taken for the detection of malaria parasites (microscopy and PCR) and antibodies against P. vivax (PvMSP119, PvAMA1) and P. falciparum (PfGLURP, PfAMA1) antigens by ELISA. Risk factors for malaria infection (positive PCR) and malaria exposure (seropositivity) were assessed by multivariate survey logistic regression models. Age-specific seroprevalence was analyzed using a reversible catalytic conversion model based on maximum likelihood for generating seroconversion rates (SCR, λ). SaTScan was used to detect spatial clusters of serology-positive individuals within each site. Results The overall parasite prevalence by PCR was low, i.e. 3.9% for P. vivax and 6.7% for P. falciparum, while the seroprevalence was substantially higher, 33.6% for P. vivax and 22.0% for P. falciparum, with major differences between study sites. Age and location (site) were significantly associated with P. vivax exposure; while location, age and outdoor occupation were associated with P. falciparum exposure. P. falciparum seroprevalence curves showed a stable transmission throughout time, while for P. vivax transmission was better described by a model with two SCRs. The spatial analysis identified well-defined clusters of P. falciparum seropositive individuals in two sites, while it detected only a very small cluster of P. vivax exposure. Conclusion The use of a single parasitological and serological malaria survey has proven to be an efficient and accurate method to characterize the species specific heterogeneity in malaria transmission at micro-geographical level as well as to identify recent changes in transmission.
Collapse
|