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Onen H, Kaddumukasa MA, Kayondo JK, Akol AM, Tripet F. A review of applications and limitations of using aquatic macroinvertebrate predators for biocontrol of the African malaria mosquito, Anopheles gambiae sensu lato. Parasit Vectors 2024; 17:257. [PMID: 38867296 PMCID: PMC11170859 DOI: 10.1186/s13071-024-06332-3] [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: 03/18/2024] [Accepted: 05/25/2024] [Indexed: 06/14/2024] Open
Abstract
Macroinvertebrate predators such as backswimmers (Heteroptera: Notonectidae), dragonflies (Odonata: Aeshnidae), and predatory diving beetles (Coleoptera: Dytiscidae) naturally inhabit aquatic ecosystems. Some aquatic ecosystems inhabited by these macroinvertebrate predator taxa equally form malaria vector larval habitats. The presence of these predators in malaria vector larval habitats can negatively impact on development, adult body size, fecundity, and longevity of the malaria vectors, which form important determinants of their fitness and future vectorial capacity. These potential negative impacts caused by aquatic macroinvertebrate predators on malaria vectors warrant their consideration as biocontrol agents in an integrated program to combat malaria. However, the use of these macroinvertebrate predators in malaria biocontrol is currently constrained by technical bottlenecks linked to their generalist predatory tendencies and often long life cycles, demanding complex rearing systems. We reviewed the literature on the use of aquatic macroinvertebrate predators for biocontrol of malaria vectors from the An. gambiae s.l. complex. The available information from laboratory and semi-field studies has shown that aquatic macroinvertebrates have the potential to consume large numbers of mosquito larvae and could thus offer an additional approaches in integrated malaria vector management strategies. The growing number of semi-field structures available in East and West Africa provides an opportunity to conduct ecological experimental studies to reconsider the potential of using aquatic macroinvertebrate predators as a biocontrol tool. To achieve a more sustainable approach to controlling malaria vector populations, additional, non-chemical interventions could provide a more sustainable approach, in comparison with the failing chemical control tools, and should be urgently considered for integration with the current mosquito vector control campaigns.
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Affiliation(s)
- Hudson Onen
- Department of Zoology, Entomology and Fisheries Sciences, College of Natural Sciences, School of Biosciences, Makerere University, P.O Box 7062, Kampala, Uganda.
- Department of Entomology, Uganda Virus Research Institute (UVRI), P.O Box 49, Entebbe, Uganda.
- Department of Biological Sciences, Faculty of Science, Kyambogo University, P.O. Box 1, Kampala, Uganda.
| | - Martha A Kaddumukasa
- Department of Biological Sciences, Faculty of Science, Kyambogo University, P.O. Box 1, Kampala, Uganda
| | - Jonathan K Kayondo
- Department of Entomology, Uganda Virus Research Institute (UVRI), P.O Box 49, Entebbe, Uganda
| | - Anne M Akol
- Department of Zoology, Entomology and Fisheries Sciences, College of Natural Sciences, School of Biosciences, Makerere University, P.O Box 7062, Kampala, Uganda
| | - Frédéric Tripet
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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Longo-Pendy NM, Sevidzem SL, Makanga BK, Ndotit-Manguiengha S, Boussougou-Sambe ST, Obame Ondo Kutomy P, Obame-Nkoghe J, Nkoghe-Nkoghe LC, Ngossanga B, Mvoubou FK, Koumba CRZ, Adegnika AA, Razack AS, Mavoungou JF, Mintsa-Nguema R. Assessment of environmental and spatial factors influencing the establishment of Anopheles gambiae larval habitats in the malaria endemic province of Woleu-Ntem, northern Gabon. Malar J 2024; 23:158. [PMID: 38773512 PMCID: PMC11106858 DOI: 10.1186/s12936-024-04980-5] [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: 01/02/2024] [Accepted: 05/10/2024] [Indexed: 05/23/2024] Open
Abstract
BACKGROUND This study aimed to assess the spatial distribution of Anopheles mosquito larval habitats and the environmental factors associated with them, as a prerequisite for the implementation of larviciding. METHODS The study was conducted in December 2021, during the transition period between the end of the short rainy season (September-November) and the short dry season (December-February). Physical, biological, and land cover data were integrated with entomological observations to collect Anopheles larvae in three major towns: Mitzic, Oyem, and Bitam, using the "dipping" method during the transition from rainy to dry season. The collected larvae were then reared in a field laboratory established for the study period. After the Anopheles mosquitoes had emerged, their species were identified using appropriate morphological taxonomic keys. To determine the influence of environmental factors on the breeding of Anopheles mosquitoes, multiple-factor analysis (MFA) and a binomial generalized linear model were used. RESULTS According to the study, only 33.1% out of the 284 larval habitats examined were found to be positive for Anopheles larvae, which were primarily identified as belonging to the Anopheles gambiae complex. The findings of the research suggested that the presence of An. gambiae complex larvae in larval habitats was associated with various significant factors such as higher urbanization, the size and type of the larval habitats (pools and puddles), co-occurrence with Culex and Aedes larvae, hot spots in ambient temperature, moderate rainfall, and land use patterns. CONCLUSIONS The results of this research mark the initiation of a focused vector control plan that aims to eradicate or lessen the larval habitats of An. gambiae mosquitoes in Gabon's Woleu Ntem province. This approach deals with the root causes of malaria transmission through larvae and is consistent with the World Health Organization's (WHO) worldwide objective to decrease malaria prevalence in regions where it is endemic.
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Affiliation(s)
- Neil-Michel Longo-Pendy
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon.
| | - Silas Lendzele Sevidzem
- Laboratoire d'Ecologie des Maladies Transmissibles (LEMAT), Université Libreville Nord (ULN), Libreville, Gabon
| | | | - Saturnin Ndotit-Manguiengha
- Institut de Recherche en Écologie Tropicale (IRET), Libreville, Gabon
- Agence Gabonaise d'Etudes et d'Observations Spatiales (AGEOS), Libreville, Gabon
| | | | - Piazzy Obame Ondo Kutomy
- Programme National de Lutte Contre Le Paludisme (PNLP), Libreville, Gabon
- Universite Cheikh Anta Diop de Dakar (UCAD), Dakar, Sénégal
| | - Judicaël Obame-Nkoghe
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon
- Université des Sciences et Techniques de Masuku (USTM), Franceville, Gabon
- Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of the Free State, Phuthaditjhaba, Republic of South Africa
| | - Lynda-Chancelya Nkoghe-Nkoghe
- Unité de Recherche en Ecologie de la Santé (URES), Centre Interdisciplinaire de Recherches Médicales de Franceville (CIRMF), Franceville, Gabon
| | | | | | | | - Ayôla Akim Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
- Institut Für Tropenmedizin, Eberhard Karls Universität, Tübingen, Germany
- Fondation Pour la Recherche Scientifique (FORS), P.O. Box 88, Cotonou, Benin
- German Center for Infection Research (DZIF), Partner site Tübingen, Tübingen, Germany
| | | | | | - Rodrigue Mintsa-Nguema
- Laboratoire d'Ecologie des Maladies Transmissibles (LEMAT), Université Libreville Nord (ULN), Libreville, Gabon
- Institut de Recherche en Écologie Tropicale (IRET), Libreville, Gabon
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Chathuranga WGD, Weeraratne TC, Abeysundara SP, Karunaratne SHPP, de Silva WAPP. Breeding site selection and co-existing patterns of tropical mosquitoes. MEDICAL AND VETERINARY ENTOMOLOGY 2023; 37:550-561. [PMID: 37060294 DOI: 10.1111/mve.12656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 03/20/2023] [Indexed: 06/19/2023]
Abstract
We investigated the physicochemical properties and the biotic interactions of breeding sites of tropical mosquito species. Field sampling was done in 12 study areas in Sri Lanka covering areas with secondary natural forests and human settlements. A total of 226 breeding sites were investigated to determine the biotic interactions and physiochemical properties of breeding water (pH, Conductivity, Dissolved Oxygen, Total Dissolved Solids and Temperature). A total of 80.5% of breeding sites from both habitats were positive for mosquito larvae of seven genera and 24 species. Orthopodomyia flavithorax (297) and Aedes albopictus (295) were dominated in tree holes of Alstonia macrophylla, Vateria copallifera and Artocarpus nobilis. Diversity indices showed that the diversity of mosquitoes is high in wet zone habitats of Sri Lanka compared to dry and intermediate zone habitats. Aedes albopictus coexisted with 11 different mosquito species while it avoided larvae of Culex fuscanus, Cx. uniformis and Tripteroides affinis. Strong positive associations were reported between Ae. albopictus and Ar. subalbatus while larvae of Or. flavithorax mosquitoes were not co-occurred with the larvae of Ae. vittatus, Ae. aegypti, Cx. sitiens, Ar. subalbatus, Anopheles spp and Tr. affinis. The findings identified the breeding adaptability and tolerance to a wide range of physiochemical properties of tropical mosquito communities.
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Affiliation(s)
- W G D Chathuranga
- Department of Zoology, Faculty of Science, University of Ruhuna, Matara, Sri Lanka
- Postgraduate Institute of Science, University of Peradeniya, Peradeniya, Sri Lanka
| | - T C Weeraratne
- Department of Zoology, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka
| | - S P Abeysundara
- Department of Statistics and Computer Science, University of Peradeniya, Peradeniya, Sri Lanka
| | - S H P P Karunaratne
- Department of Zoology, Faculty of Science, University of Peradeniya, Peradeniya, Sri Lanka
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Dambach P, Bärnighausen T, Yadouleton A, Dambach M, Traoré I, Korir P, Ouedraogo S, Nikiema M, Sauerborn R, Becker N, Louis VR. Is biological larviciding against malaria a starting point for integrated multi-disease control? Observations from a cluster randomized trial in rural Burkina Faso. PLoS One 2021; 16:e0253597. [PMID: 34143831 PMCID: PMC8213177 DOI: 10.1371/journal.pone.0253597] [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: 10/29/2020] [Accepted: 06/08/2021] [Indexed: 11/29/2022] Open
Abstract
Objectives To evaluate the impact of anti-malaria biological larviciding with Bacillus thuringiensis israelensis on non-primary target mosquito species in a rural African setting. Methods A total of 127 villages were distributed in three study arms, each with different larviciding options in public spaces: i) no treatment, ii) full or iii) guided intervention. Geographically close villages were grouped in clusters to avoid contamination between treated and untreated villages. Adult mosquitoes were captured in light traps inside and outside houses during the rainy seasons of a baseline and an intervention year. After enumeration, a negative binomial regression was used to determine the reductions achieved in the different mosquito species through larviciding. Results Malaria larviciding interventions showed only limited or no impact against Culex mosquitoes; by contrast, reductions of up to 34% were achieved against Aedes when all detected breeding sites were treated. Culex mosquitoes were captured in high abundance in semi-urban settings while more Aedes were found in rural villages. Conclusions Future malaria larviciding programs should consider expanding onto the breeding habitats of other disease vectors, such as Aedes and Culex and evaluate their potential impact. Since the major cost components of such interventions are labor and transport, other disease vectors could be targeted at little additional cost.
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Affiliation(s)
- Peter Dambach
- Institute for Global Health, University Hospital Heidelberg, Heidelberg, Germany
- * E-mail:
| | - Till Bärnighausen
- Institute for Global Health, University Hospital Heidelberg, Heidelberg, Germany
| | - Anges Yadouleton
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Benin
| | - Martin Dambach
- Institute of Zoology, University of Cologne, Cologne, Germany
| | - Issouf Traoré
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | - Patricia Korir
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | | | | | - Rainer Sauerborn
- Institute for Global Health, University Hospital Heidelberg, Heidelberg, Germany
| | - Norbert Becker
- German Mosquito Control Association (KABS), Speyer, Germany
| | - Valérie R. Louis
- Institute for Global Health, University Hospital Heidelberg, Heidelberg, Germany
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Foley DH, Wilkerson RC, Kim HC, Klein TA, Kim MS, Li C, Levin DM, Rueda LM. Wing size and parity as markers of cohort demography for potential Anopheles (Culicidae: Diptera) malaria vectors in the Republic of Korea. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2020; 45:366-379. [PMID: 33207064 DOI: 10.1111/jvec.12406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/15/2020] [Indexed: 06/11/2023]
Abstract
Wing lengths of parous (P) and nulliparous (NP) PCR-identified female Anopheles belenrae, An. kleini, An. pullus, and An. sinensis were determined from weekly trap collections at Camp Humphreys (CH), Ganghwa Island (GH), and Warrior Base (WB), Republic of Korea (ROK) during Jun-Oct, 2009. Wing length was greatest at the beginning and end of the study period. Wing length of NPs tended to be less than that of Ps before the period of maximum greening (Jul-Aug) but greater thereafter. Larger specimens tended to be Ps, and weekly wing length of Ps appeared less variable than NPs, possibly due to selection. A bimodal wing length frequency distribution of An. sinensis suggested two forms comprising small- (≤4.5 mm, SW) and large-winged females (>4.5 mm, LW). LW comprised the majority of peaks in abundance, however %SW, while still a minority, often increased during these times suggesting a density-dependent effect. At WB and GH, a two to three-week periodicity in %SW was obvious for An. sinensis and An. kleini. Analyses of weather station and satellite data showed that smaller-winged An. sinensis were associated with warmer, more humid, and greener times of the year. SW and LW specimens possibly result from agricultural practices that are common across large areas; regular synchronous peaks of SW and LW were observed from different sites. Peaks in SW Ps followed peaks in NPs in a 'ripple effect' one to two weeks apart, suggesting that wing length combined with parity could be used to follow the emergence and survival of mosquito cohorts.
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Affiliation(s)
- Desmond H Foley
- Walter Reed Biosystematics Unit, Department of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, U.S.A
- Entomology Department, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20013, U.S.A
| | - Richard C Wilkerson
- Walter Reed Biosystematics Unit, Department of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, U.S.A
- Entomology Department, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20013, U.S.A
| | - Heung Chul Kim
- Force Health Protection and Preventive Medicine, US Army Medical Activity-Korea, 65th Medical Brigade, Unit #15281, APO AP 96271-5281
| | - Terry A Klein
- Force Health Protection and Preventive Medicine, US Army Medical Activity-Korea, 65th Medical Brigade, Unit #15281, APO AP 96271-5281
| | - Myung-Soon Kim
- Force Health Protection and Preventive Medicine, US Army Medical Activity-Korea, 65th Medical Brigade, Unit #15281, APO AP 96271-5281
| | - Cong Li
- Walter Reed Biosystematics Unit, Department of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, U.S.A
| | - David M Levin
- Walter Reed Biosystematics Unit, Department of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, U.S.A
| | - Leopoldo M Rueda
- Walter Reed Biosystematics Unit, Department of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD, 20910, U.S.A
- Entomology Department, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20013, U.S.A
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Gowelo S, Chirombo J, Koenraadt CJM, Mzilahowa T, van den Berg H, Takken W, McCann RS. Characterisation of anopheline larval habitats in southern Malawi. Acta Trop 2020; 210:105558. [PMID: 32485166 PMCID: PMC7673143 DOI: 10.1016/j.actatropica.2020.105558] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Increasing the knowledgebase of anopheline larval ecology could enable targeted deployment of malaria control efforts and consequently reduce costs of implementation. In Malawi, there exists a knowledge gap in anopheline larval ecology and, therefore, basis for targeted deployment of larval source management (LSM) for malaria control, specifically larvicides. We set out to characterize anopheline larval habitats in the Majete area of Malawi on the basis of habitat ecology and anopheline larval productivity to create a basis for larval control initiatives in the country. METHODS Longitudinal surveys were conducted in randomly selected larval habitats over a period of fifteen months in Chikwawa district, southern Malawi. Biotic and abiotic parameters of the habitats were modelled to determine their effect on the occurrence and densities of anopheline larvae. RESULTS Seventy aquatic habitats were individually visited between 1-7 times over the study period. A total of 5,123 immature mosquitoes (3,359 anophelines, 1,497 culicines and 267 pupae) were collected. Anopheline and culicine larvae were observed in sympatry in aquatic habitats. Of the nine habitat types followed, dams, swamps, ponds, borehole runoffs and drainage channels were the five most productive habitat types for anopheline mosquitoes. Anopheline densities were higher in aquatic habitats with bare soil making up part of the surrounding land cover (p<0.01) and in aquatic habitats with culicine larvae (p<0.01) than in those surrounded by vegetation and not occupied by culicine larvae. Anopheline densities were significantly lower in highly turbid habitats than in clearer habitats (p<0.01). Presence of predators in the aquatic habitats significantly reduced the probability of anopheline larvae being present (p=0.04). CONCLUSIONS Anopheline larval habitats are widespread in the study area. Presence of bare soil, culicine larvae, predators and the level of turbidity of water are the main determinants of anopheline larval densities in aquatic habitats in Majete, Malawi. While the most productive aquatic habitats should be prioritised, for the most effective control of vectors in the area all available aquatic habitats should be targeted, even those that are not characterized by the identified predictors. Further research is needed to determine whether targeted LSM would be cost-effective when habitat characterisation is included in cost analyses and to establish what methods would make the characterisation of habitats easier.
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Affiliation(s)
- Steven Gowelo
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands; Training and Research Unit of Excellence, School of Public Health, College of Medicine, Blantyre, Malawi
| | - James Chirombo
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | | | - Henk van den Berg
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands
| | - Willem Takken
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands.
| | - Robert S McCann
- Laboratory of Entomology, Wageningen University & Research, Wageningen, The Netherlands; Training and Research Unit of Excellence, School of Public Health, College of Medicine, Blantyre, Malawi; Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
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Buxton M, Cuthbert RN, Dalu T, Nyamukondiwa C, Wasserman RJ. Cattle-induced eutrophication favours disease-vector mosquitoes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 715:136952. [PMID: 32007900 DOI: 10.1016/j.scitotenv.2020.136952] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 01/24/2020] [Accepted: 01/24/2020] [Indexed: 06/10/2023]
Abstract
Free-range cattle rearing in arid landscapes contributes profoundly to ecosystem degradation. Cattle dung nutrification in aquatic habitats potentially shapes species diversity and abundance due to resource availability. These nutrient-enriched environments may increase oviposition by mosquitoes and influence proliferation of disease vectors. Here, we examined mosquito larval abundance of Culex pipiens pipiens (culicine) and an unidentified Anopheles (anopheline) species across different concentration treatments of nutrient (cattle dung) loadings (T1-T4; 1 g L-1, 2 g L-1, 4 g L-1 and 8 g L-1, respectively) in a randomised outdoor mesocosm experiment. The experiment was run for two weeks post-dung inoculation (Day 7 to 21), with mosquito larvae collected (Day 14 and 21), identified and quantified. Higher dung nutrient concentrations significantly increased mosquito larval abundance relative to dung-free controls. Culicine larvae were 26-times more abundant than anopheline on average. Higher dung concentrations also tended to promote more rapid development in larval mosquitoes. With no colonisation by mosquito larvae in the control treatments, we conclude that the input of dung in aquatic ecosystems promotes vector development and abundance with the potential to increase risk of mosquito-borne infections. We therefore recommend sustainable management policies that tackle likely ecological disservices attributable to free-ranging livestock communities.
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Affiliation(s)
- Mmabaledi Buxton
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
| | - Ross N Cuthbert
- School of Biological Sciences, Queen's University Belfast, Belfast BT9 5DL, United Kingdom of Great Britain and Northern Ireland
| | - Tatenda Dalu
- Department of Ecology and Resource Management, University of Venda, Thohoyandou 0950, South Africa
| | - Casper Nyamukondiwa
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Palapye, Botswana
| | - Ryan J Wasserman
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Palapye, Botswana.
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Collins CM, Bonds JAS, Quinlan MM, Mumford JD. Effects of the removal or reduction in density of the malaria mosquito, Anopheles gambiae s.l., on interacting predators and competitors in local ecosystems. MEDICAL AND VETERINARY ENTOMOLOGY 2019; 33:1-15. [PMID: 30044507 PMCID: PMC6378608 DOI: 10.1111/mve.12327] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 05/23/2018] [Accepted: 06/15/2018] [Indexed: 05/23/2023]
Abstract
New genetic control methods for mosquitoes may reduce vector species without direct effects on other species or the physical environment common with insecticides or drainage. Effects on predators and competitors could, however, be a concern as Anopheles gambiae s.l. is preyed upon in all life stages. We overview the literature and assess the strength of the ecological interactions identified. Most predators identified consume many other insect species and there is no evidence that any species preys exclusively on any anopheline mosquito. There is one predatory species with a specialisation on blood-fed mosquitoes including An. gambiae s.l.. Evarcha culicivora is a jumping spider, known as the vampire spider, found around Lake Victoria. There is no evidence that these salticids require Anopheles mosquitoes and will readily consume blood-fed Culex. Interspecific competition studies focus on other mosquitoes of larval habitats. Many of these take place in artificial cosms and give contrasting results to semi-field studies. This may limit their extrapolation regarding the potential impact of reduced An. gambiae numbers. Previous mosquito control interventions are informative and identify competitive release and niche opportunism; so while the identity and relative abundance of the species present may change, the biomass available to predators may not.
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Affiliation(s)
- C. M. Collins
- Centre for Environmental PolicyImperial College LondonLondonU.K.
| | - J. A. S. Bonds
- Bonds Consulting Group LLCPanama City Beach, FloridaU.S.A.
| | - M. M. Quinlan
- Centre for Environmental PolicyImperial College LondonLondonU.K.
| | - J. D. Mumford
- Centre for Environmental PolicyImperial College LondonLondonU.K.
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Mazigo E, Kidima W, Myamba J, Kweka EJ. The impact of Anopheles gambiae egg storage for mass rearing and production success. Malar J 2019; 18:52. [PMID: 30808356 PMCID: PMC6390356 DOI: 10.1186/s12936-019-2691-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/21/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Mass rearing requires a large colony from which male individuals can be harvested for sterilization and release. Attention is needed when monitoring life parameters of the reared population, knowing that any variations within the target population would lead to mismatching between two populations. The aim of this study was to assess the impact of Anopheles gambiae sensu stricto (s.s.) egg storage on hatchability and life history traits. For each parameter, comparison was made between freshly laid and stored eggs in three densities (40, 80, 120 eggs). METHODS Anopheles gambiae s.s. freshly laid eggs were collected from the Tropical Pesticide Research Institute (TPRI) insectary. Eggs to be stored were kept at - 20 °C for 10 min and then transferred to refrigerators at 4 °C for intervals of 5, 10, 15, 20, and 25 days. After respective storage days, the eggs were transferred from refrigerators to ambient temperature of (25 ± 2) °C for 24 h and then placed in incubators for 24 h. Thereafter eggs were hatched. The egg hatchability, emerged larvae development, larvae survival and emerged adult sex ratios were monitored. RESULTS This study found that hatching rates decreased with increase in storage time. The difference was significant in eggs stored for 10 and 15 days (P < 0.05). There were no significant differences in hatching rates between An. gambiae eggs stored for 5 days and freshly hatched eggs (P > 0.05). Anopheles larvae development (L1 to pupae) was not significantly affected by storage time across all hatching densities. The study also found that larvae survival decreased with increase in egg storage time. However, there was no significant difference between larvae from freshly hatched eggs and those from eggs at 5 and 10 storage days (P > 0.05) but not for eggs stored for 15 days. Furthermore, there was a decrease in emerged adult males and increase in females relative to increased time of egg storage. The difference was significant (P < 0.05) at 15 storage days but not for eggs stored for 5 and 10 days (in triplicate densities). CONCLUSION From this study it was concluded that storing An. gambiae eggs at 4 °C and 48 ± 2% relative humidity (RH) for 5 days is the optimal condition and time that did not affect egg hatching rates, larval development and survivorship and emerged adult mosquito sex ratio.
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Affiliation(s)
- Ernest Mazigo
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Winifrida Kidima
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Joseph Myamba
- National Institute for Medical Research, Amani Medical Research Centre, P.O. Box 81, Muheza, Tanzania
| | - Eliningaya J Kweka
- Department of Medical Parasitology, School of Medicine, Catholic University of Health and Allied Sciences-Bugando, P.O. Box 1464, Mwanza, Tanzania. .,Division of Livestock and Human Disease Vector Control, Tropical Pesticides Research Institute, P.O.Box 3024, Arusha, Tanzania.
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Emidi B, Kisinza WN, Mmbando BP, Malima R, Mosha FW. Effect of physicochemical parameters on Anopheles and Culex mosquito larvae abundance in different breeding sites in a rural setting of Muheza, Tanzania. Parasit Vectors 2017. [PMID: 28645303 PMCID: PMC5482952 DOI: 10.1186/s13071-017-2238-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Basiliana Emidi
- Kilimanjaro Christian Medical University College, P.O. Box 2240, Moshi, Tanzania. .,National Institute for Medical Research, Headquarters, P.O. Box 9653, Dar es Salaam, Tanzania.
| | - William N Kisinza
- National Institute for Medical Research, Amani Centre, P.O. Box 81, Muheza, Tanzania
| | - Bruno P Mmbando
- National Institute for Medical Research, Tanga Centre, P.O. Box 5004, Tanga, Tanzania
| | - Robert Malima
- National Institute for Medical Research, Amani Centre, P.O. Box 81, Muheza, Tanzania
| | - Franklin W Mosha
- Kilimanjaro Christian Medical University College, P.O. Box 2240, Moshi, Tanzania
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11
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Shah RM, Ali Q, Alam M, Shad SA, Majeed S, Riaz M, Binyameen M. Larval Habitat Substrates Could Affect the Biology and Vectorial Capacity of Culex quinquefasciatus (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2017; 54:638-645. [PMID: 28025248 DOI: 10.1093/jme/tjw211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 11/02/2016] [Indexed: 06/06/2023]
Abstract
Culex quinquefasciatus Say is an important disease vector throughout much of the world. Experiments were conducted to determine the effects of different larval habitat substrates on the fitness and biting efficiency of Cx. quinquefasciatus adults. Our findings indicate that the development time (egg to adult) of larvae reared in irrigation water was 8.63 d while that of larvae reared in distilled water was 17.10 d (Effect size = 0.95). However, the rate of adult emergence was similar for all the tested treatments. Furthermore, the mean weight of an egg raft varied between larval habitats: distilled water (1.83 mg), rainfall water (1.25 mg), irrigation water (1.52 mg), and sewerage water (2.52 mg) (Effect size = 0.91). But, the fecundity (eggs per female) and hatchability (%) were statistically similar in all the rearing mediums (Effect size = 0.79). Longevity of females in all the tested populations did not differ significantly (Effect size = 0.91). The mean relative growth rates of larvae reared in tap water (0.80) and distilled water (0.86) habitats were lower than growth rates in all other rearing habitats (Effect size = 0.96). The intrinsic rate of natural increase in tap water (0.27) and irrigation water (0.35) was significantly higher than that in distilled water (0.09) and sewerage water (0.16) (Effect size = 0.84). Adults reared in rain water had the highest biting efficiency among all the tested populations. These results provide useful information for the management of Cx. quinquefasciatus.
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Affiliation(s)
- Rizwan Mustafa Shah
- Department of Entomology, Faculty of Agriculture Sciences & Technology, Bahauddin Zakariya University, Multan 60800, Pakistan (; ; ; ; ; )
| | - Qasim Ali
- Department of Entomology, Faculty of Agriculture Sciences & Technology, Bahauddin Zakariya University, Multan 60800, Pakistan (; ; ; ; ; )
| | - Mehboob Alam
- Department of Entomology, Faculty of Agriculture Sciences & Technology, Bahauddin Zakariya University, Multan 60800, Pakistan (; ; ; ; ; )
| | - Sarfraz Ali Shad
- Department of Entomology, Faculty of Agriculture Sciences & Technology, Bahauddin Zakariya University, Multan 60800, Pakistan (; ; ; ; ; )
| | - Shahid Majeed
- Department of Entomology, University of Agriculture, Faisalabad, Punjab 38000, Pakistan ( )
- US-Pakistan Center for Advanced Studies in Agriculture Food Security (US-PCAS-AFS), University of Agriculture Faisalabad, Punjab, Pakistan, 38000
| | - Muhammad Riaz
- Department of Food Science and Technology, College of Life Sciences, Sejong University, Gunja-dong 98, Gwangin-gu, Seoul 143-747, Republic of Korea
| | - Muhammad Binyameen
- Department of Entomology, Faculty of Agriculture Sciences & Technology, Bahauddin Zakariya University, Multan 60800, Pakistan (; ; ; ; ; )
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12
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Farajzadeh M, Halimi M, Ghavidel Y, Delavari M. Spatiotemporal Anopheles Population Dynamics, Response to Climatic Conditions: The Case of Chabahar, South Baluchistan, Iran. Ann Glob Health 2017; 81:694-704. [PMID: 27036728 DOI: 10.1016/j.aogh.2015.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND An understanding of the factors that affect the abundance of Anopheline species provides an opportunity to better understand the dynamics of malaria transmission in different regions. Chabahar, located south east of Iran, is the most malarious region in the country. OBJECTIVE The main aim of this study was to quantify the spatiotemporal Anopheles population dynamics, response to climatic conditions in Chabahar. METHODS Satellite-based and land-based climatic data were used as explanatory variables. Monthly caught mosquitoes in 6 village sites of Chabahar were used as dependent variable. The spatiotemporal associations were first investigated by inspection of scatter plots and single variable regression analysis. A multivariate linear regression model was developed to reveal the association between environmental variables and the monthly mosquito abundance at a 95% confidence level (P ≤ 0.5). FINDINGS Results indicated that Anopheles mosquitoes can be found all year in Chabahar with 2 significant seasonal peaks from March to June (primary peak) and September to November (secondary peak). Results of the present study showed that 0.77 of yearly mosquito abundance emerges in the thermal range of 24°C to 30°C and the humidity range of 0.70 to 0.80 in Chabahar. CONCLUSION According to the developed multivariate linear model, 0.88 of temporal variance of mosquito abundance, nighttime land surface temperature, and relative humidity of 15 Universal Time Coordinated (18.30 Iran) are the main drivers of mosquito population dynamics in Chabahar.
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Affiliation(s)
| | - Mansour Halimi
- Department of Climatology, TarbiatModares University, Tehran, Iran.
| | - Yousef Ghavidel
- Department of Climatology, TarbiatModares University, Tehran, Iran
| | - Mahdi Delavari
- Department of Medical Parasitology and Mycology, Faculty of Medicine, Kashan University of Medical Science, Kashan, Iran
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13
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Vantaux A, Lefèvre T, Cohuet A, Dabiré KR, Roche B, Roux O. Larval nutritional stress affects vector life history traits and human malaria transmission. Sci Rep 2016; 6:36778. [PMID: 27827429 PMCID: PMC5101500 DOI: 10.1038/srep36778] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/17/2016] [Indexed: 11/15/2022] Open
Abstract
Exposure to stress during an insect’s larval development can have carry-over effects on adult life history traits and susceptibility to pathogens. We investigated the effects of larval nutritional stress for the first time using field mosquito vectors and malaria parasites. In contrast to previous studies, we show that larval nutritional stress may affect human to mosquito transmission antagonistically: nutritionally deprived larvae showed lower parasite prevalence for only one gametocyte carrier; they also had lower fecundity. However, they had greater survival rates that were even higher when infected. When combining these opposing effects into epidemiological models, we show that larval nutritional stress induced a decrease in malaria transmission at low mosquito densities and an increase in transmission at high mosquito densities, whereas transmission by mosquitoes from well-fed larvae was stable. Our work underscores the importance of including environmental stressors towards understanding host–parasite dynamics to improve disease transmission models and control.
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Affiliation(s)
- Amélie Vantaux
- MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle), UMR IRD 224-CNRS 5290-UM, Montpellier, France.,Institut de Recherche en Sciences de la Santé (IRSS), 01BP171 Bobo-Dioulasso, Burkina Faso
| | - Thierry Lefèvre
- MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle), UMR IRD 224-CNRS 5290-UM, Montpellier, France.,Institut de Recherche en Sciences de la Santé (IRSS), 01BP171 Bobo-Dioulasso, Burkina Faso
| | - Anna Cohuet
- MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle), UMR IRD 224-CNRS 5290-UM, Montpellier, France.,Institut de Recherche en Sciences de la Santé (IRSS), 01BP171 Bobo-Dioulasso, Burkina Faso
| | - Kounbobr Roch Dabiré
- Institut de Recherche en Sciences de la Santé (IRSS), 01BP171 Bobo-Dioulasso, Burkina Faso.,Centre Muraz, Bobo-Dioulasso, Burkina Faso
| | - Benjamin Roche
- UMMISCO (Unité de Modélisation Mathématique et Informatique des Systèmes Complexes), UMI IRD/UPMC 209, Bondy, France
| | - Olivier Roux
- MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle), UMR IRD 224-CNRS 5290-UM, Montpellier, France.,Institut de Recherche en Sciences de la Santé (IRSS), 01BP171 Bobo-Dioulasso, Burkina Faso
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14
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Shapiro LLM, Murdock CC, Jacobs GR, Thomas RJ, Thomas MB. Larval food quantity affects the capacity of adult mosquitoes to transmit human malaria. Proc Biol Sci 2016; 283:20160298. [PMID: 27412284 PMCID: PMC4947883 DOI: 10.1098/rspb.2016.0298] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 06/21/2016] [Indexed: 12/22/2022] Open
Abstract
Adult traits of holometabolous insects are shaped by conditions experienced during larval development, which might impact interactions between adult insect hosts and parasites. However, the ecology of larval insects that vector disease remains poorly understood. Here, we used Anopheles stephensi mosquitoes and the human malaria parasite Plasmodium falciparum, to investigate whether larval conditions affect the capacity of adult mosquitoes to transmit malaria. We reared larvae in two groups; one group received a standard laboratory rearing diet, whereas the other received a reduced diet. Emerging adult females were then provided an infectious blood meal. We assessed mosquito longevity, parasite development rate and prevalence of infectious mosquitoes over time. Reduced larval food led to increased adult mortality and caused a delay in parasite development and a slowing in the rate at which parasites invaded the mosquito salivary glands, extending the time it took for mosquitoes to become infectious. Together, these effects increased transmission potential of mosquitoes in the high food regime by 260-330%. Such effects have not, to our knowledge, been shown previously for human malaria and highlight the importance of improving knowledge of larval ecology to better understand vector-borne disease transmission dynamics.
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Affiliation(s)
- Lillian L M Shapiro
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Courtney C Murdock
- College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Gregory R Jacobs
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Rachel J Thomas
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Matthew B Thomas
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA 16802, USA
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15
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Christiansen-Jucht CD, Parham PE, Saddler A, Koella JC, Basáñez MG. Larval and adult environmental temperatures influence the adult reproductive traits of Anopheles gambiae s.s. Parasit Vectors 2015; 8:456. [PMID: 26382035 PMCID: PMC4573685 DOI: 10.1186/s13071-015-1053-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 08/19/2015] [Indexed: 01/10/2023] Open
Abstract
Background Anopheles mosquito life-history parameters and population dynamics strongly influence malaria transmission, and environmental factors, particularly temperature, strongly affect these parameters. There are currently some studies on how temperature affects Anopheles gambiae s.s. survival but very few exist examining other life-history traits. We investigate here the effect of temperature on population dynamics parameters. Methods Anopheles gambiae s.s. immatures were reared individually at 23 ± 1 °C, 27 ± 1 °C, 31 ± 1 °C, and 35 ± 1 °C, and adults were held at their larval temperature or at one of the other temperatures. Larvae were checked every 24 h for development to the next stage and measured for size; wing length was measured as a proxy for adult size. Females were blood fed three times, and the number of females feeding and laying eggs was counted. The numbers of eggs and percentage of eggs hatched were recorded. Results Increasing temperatures during the larval stages resulted in significantly smaller larvae (p = 0.005) and smaller adults (p < 0.001). Adult temperature had no effect on the time to egg laying, and the larval temperature of adults only affected the incubation period of the first egg batch. Temperature influenced the time to hatching of eggs, as well as the time to development at every stage. The number of eggs laid was highest when adults were kept at 27 °C, and lowest at 31 °C, and higher adult temperatures decreased the proportion of eggs hatching after the second and third blood meal. Higher adult temperatures significantly decreased the probability of blood feeding, but the larval temperature of adults had no influence on the probability of taking a blood meal. Differences were observed between the first, second, and third blood meal in the times to egg laying and hatching, number of eggs laid, and probabilities of feeding and laying eggs. Conclusions Our study shows that environmental temperature during the larval stages as well as during the adult stages affects Anopheles life-history parameters. Data on how temperature and other climatic factors affect vector life-history parameters are necessary to parameterise more reliably models predicting how global warming may influence malaria transmission. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1053-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Céline D Christiansen-Jucht
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, Norfolk Place, London, W2 1PG, UK.
| | - Paul E Parham
- Department of Public Health and Policy, Faculty of Health and Life Sciences, University of Liverpool, 33 Finsbury Square, London, EC2A 1AG, UK.
| | - Adam Saddler
- Department of Epidemiology and Public Health, Health Interventions Unit, Swiss TPH, Basel, Switzerland.
| | - Jacob C Koella
- Faculté des Sciences, Institut de Biologie, Université de Neuchâtel, Rue Emile-Argand 11, CH-2000, Neuchâtel, Switzerland.
| | - María-Gloria Basáñez
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, Norfolk Place, London, W2 1PG, UK.
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16
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Juliano SA, Ribeiro GS, Maciel-de-Freitas R, Castro MG, Codeço C, Lourenço-de-Oliveira R, Lounibos LP. She's a femme fatale: low-density larval development produces good disease vectors. Mem Inst Oswaldo Cruz 2015; 109:1070-7. [PMID: 25591112 PMCID: PMC4325623 DOI: 10.1590/0074-02760140455] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 12/02/2014] [Indexed: 11/21/2022] Open
Abstract
Two hypotheses for how conditions for larval mosquitoes affect vectorial capacity make opposite predictions about the relationship of adult size and frequency of infection with vector-borne pathogens. Competition among larvae produces small adult females. The competition-susceptibility hypothesis postulates that small females are more susceptible to infection and predicts frequency of infection should decrease with size. The competition-longevity hypothesis postulates that small females have lower longevity and lower probability of becoming competent to transmit the pathogen and thus predicts frequency of infection should increase with size. We tested these hypotheses for Aedes aegypti in Rio de Janeiro, Brazil, during a dengue outbreak. In the laboratory, longevity increases with size, then decreases at the largest sizes. For field-collected females, generalised linear mixed model comparisons showed that a model with a linear increase of frequency of dengue with size produced the best Akaike's information criterion with a correction for small sample sizes (AICc). Consensus prediction of three competing models indicated that frequency of infection increases monotonically with female size, consistent with the competition-longevity hypothesis. Site frequency of infection was not significantly related to site mean size of females. Thus, our data indicate that uncrowded, low competition conditions for larvae produce the females that are most likely to be important vectors of dengue. More generally, ecological conditions, particularly crowding and intraspecific competition among larvae, are likely to affect vector-borne pathogen transmission in nature, in this case via effects on longevity of resulting adults. Heterogeneity among individual vectors in likelihood of infection is a generally important outcome of ecological conditions impacting vectors as larvae.
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Affiliation(s)
- Steven A Juliano
- School of Biological Sciences, Illinois State University, Normal, IL, USA
| | | | - Rafael Maciel-de-Freitas
- Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | - Márcia G Castro
- Laboratório de Transmissores de Hematozoários, Instituto Oswaldo Cruz, Rio de Janeiro, RJ, Brasil
| | | | | | - L Philip Lounibos
- Florida Medical Entomology Laboratory, University of Florida, Gainesville, FL, USA
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17
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Chobu M, Nkwengulila G, Mahande AM, Mwang'onde BJ, Kweka EJ. Direct and indirect effect of predators on Anopheles gambiae sensu stricto. Acta Trop 2015; 142:131-7. [PMID: 25438260 DOI: 10.1016/j.actatropica.2014.11.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 11/07/2014] [Accepted: 11/21/2014] [Indexed: 11/19/2022]
Abstract
The increased insecticides resistance by vectors and the ecological harm imposed by insecticides to beneficial organisms drawback mosquitoes chemical control efforts. Biological control would reduce insecticides tolerance and yet biodiversity friend. The predatory and non-predatory effects of Gambusia affinis and Carassius auratus on gravid Anopheles gambiae sensu strict and larvae survivorship were assessed. In determining predation rate, a single starved predator was exposed to third instar larvae of An. gambiae s.s. in different densities 20, 60 and 100. Six replicates in each of the densities for both predators, G. affinis and C. auratus, were set up. The larvae densities were monitored in every 12 and 24 h. In assessing indirect effects: An. gambiae s.s. first instar larvae of three densities 20, 60 and 100 were reared in water from a predator habitat and water from non-predator habitat. Larvae were monitored until they emerged to adults where larval survivorship and sex ratio (Female to total emerged mosquitoes) of the emerged adult from both water habitats were determined. Oviposition preference: twenty gravid females of An. gambiae s.s. were provided with three oviposition choices, one containing water from predator habitat without a predator, the second with water from a predator with a predator and the third with water from non-predatory habitat. The number of eggs laid on each container was counted daily. There were 20 replicates for each predator, G. affinis and C. auratus. Survivorship of An. gambiae s.s. larvae reared in water from non-predator habitat was higher than those reared in water from the predator habitats. Many males emerged in water from non-predatory water habitats while more females emerged from predator's habitats water. More eggs laid in tap water than in water from predator habitat and water from predator habitat with live predator. In 24 h, a starved C. auratus and G. affinis were able to consume 100% of the 3rd instar larvae. The findings from this study suggest that G. affinis and C. auratus may be useful in regulating mosquito populations in favour of beneficial insects. However, a small scale trial shall be needed in complex food chain system to ascertain the observed predation and kairomones effects.
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Affiliation(s)
- Mariam Chobu
- College of Natural and Applied Sciences, Department of Zoology and Wildlife Conservation, University of Dar es salaam, P.O. Box 35064, Dar es salaam, Tanzania.
| | - Gamba Nkwengulila
- College of Natural and Applied Sciences, Department of Zoology and Wildlife Conservation, University of Dar es salaam, P.O. Box 35064, Dar es salaam, Tanzania.
| | - Aneth M Mahande
- Tropical Pesticides Research Institute, Division of Livestock and Human Diseases Vector Control, Mosquito Section, P.O. Box 3024, Arusha, Tanzania.
| | - Beda J Mwang'onde
- Tropical Pesticides Research Institute, Division of Livestock and Human Diseases Vector Control, Mosquito Section, P.O. Box 3024, Arusha, Tanzania.
| | - Eliningaya J Kweka
- Tropical Pesticides Research Institute, Division of Livestock and Human Diseases Vector Control, Mosquito Section, P.O. Box 3024, Arusha, Tanzania; Department of Medical Parasitology and Entomology, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania; Pan African Mosquito Control Association (PAMCA), Tanzania(1).
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18
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Kivuyo HS, Mbazi PH, Kisika DS, Munga S, Rumisha SF, Urasa FM, Kweka EJ. Performance of five food regimes on Anopheles gambiae senso stricto larval rearing to adult emergence in insectary. PLoS One 2014; 9:e110671. [PMID: 25340408 PMCID: PMC4207715 DOI: 10.1371/journal.pone.0110671] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 09/05/2014] [Indexed: 11/24/2022] Open
Abstract
Background Rearing of Anopheles gambiae s.s mosquitoes in insectary with quality cheap food sources is of paramount importance for better and healthy colony. This study evaluated larval survival and the development rate of aquatic stages of An.gambiae s.s under five food regimes; tetramin fish food (a standard insectary larval food), maize pollen, Cerelac, green filamentous algae and dry powdered filamentous algae. Methods Food materials were obtained from different sources, cerelac was made locally, fresh filamentous algae was taken from water bodies, dry filamentous algae was ground to powder after it was dried under shade, and maize pollen was collected from the flowering maize. Each food source type was used to feed three densities of mosquito larvae 20, 60, and 100 in six replicates each. Larval age structure was monitored daily until pupation and subsequently adult emergence. Tetramin was used and taken as a standard food source for An. gambiae s.s. larvae feeding in Insectary. Results Larval survivorship using maize pollen and Tetramin fish food was statistically insignificant (P = 0.564). However when compared to other food regime survivorship was significantly different with Tetramin fish food performing better than cerelac (P<0.001), dry algae (P<0.001) and fresh algae (P<0.001). The pupation rates and sex ratio of emerging adults had significant differences among the food regimes. Conclusion The findings of this study have shown that maize pollen had closely similar nutritional value for larval survivorship to tetramin fish food, a standard larvae food in insectary. Further studies are required to assess the effect of food sources on various life traits of the emerged adults.
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Affiliation(s)
- Happiness S. Kivuyo
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar-es-salaam, Dar-es-salaam, Tanzania
| | - Paschal H. Mbazi
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar-es-salaam, Dar-es-salaam, Tanzania
| | - Denis S. Kisika
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar-es-salaam, Dar-es-salaam, Tanzania
| | - Stephen Munga
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Susan F. Rumisha
- National Institute for Medical Research, Dar es Salaam, Tanzania
| | - Felister M. Urasa
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar-es-salaam, Dar-es-salaam, Tanzania
| | - Eliningaya J. Kweka
- Tropical Pesticides Research Institute, Division Of Livestock And Human Diseases Vector Control, Mosquito Section, Arusha, Tanzania
- Department of Medical Parasitology and Entomology, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
- * E-mail:
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Gómez GF, Márquez EJ, Gutiérrez LA, Conn JE, Correa MM. Geometric morphometric analysis of Colombian Anopheles albimanus (Diptera: Culicidae) reveals significant effect of environmental factors on wing traits and presence of a metapopulation. Acta Trop 2014; 135:75-85. [PMID: 24704285 DOI: 10.1016/j.actatropica.2014.03.020] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Revised: 03/20/2014] [Accepted: 03/24/2014] [Indexed: 01/24/2023]
Abstract
Anopheles albimanus is a major malaria mosquito vector in Colombia. In the present study, wing variability (size and shape) in An. albimanus populations from Colombian Maracaibo and Chocó bio-geographical eco-regions and the relationship of these phenotypic traits with environmental factors were evaluated. Microsatellite and morphometric data facilitated a comparison of the genetic and phenetic structure of this species. Wing size was influenced by elevation and relative humidity, whereas wing shape was affected by these two variables and also by rainfall, latitude, temperature and eco-region. Significant differences in mean shape between populations and eco-regions were detected, but they were smaller than those at the intra-population level. Correct assignment based on wing shape was low at the population level (<58%) and only slightly higher (>70%) at the eco-regional level, supporting the low population structure inferred from microsatellite data. Wing size was similar among populations with no significant differences between eco-regions. Population relationships in the genetic tree did not agree with those from the morphometric data; however, both datasets consistently reinforced a panmictic population of An. albimanus. Overall, site-specific population differentiation is not strongly supported by wing traits or genotypic data. We hypothesize that the metapopulation structure of An. albimanus throughout these Colombian eco-regions is favoring plasticity in wing traits, a relevant characteristic of species living under variable environmental conditions and colonizing new habitats.
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Affiliation(s)
- Giovan F Gómez
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | - Edna J Márquez
- Facultad de Ciencias, Universidad Nacional de Colombia, Medellín, Colombia.
| | - Lina A Gutiérrez
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
| | - Jan E Conn
- Wadsworth Center, New York State Department of Health, Slingerlands, 12159 NY, USA; Department of Biomedical Sciences, School of Public Health, State University of New York, Albany, 12222 NY, USA.
| | - Margarita M Correa
- Grupo de Microbiología Molecular, Escuela de Microbiología, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
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Mbare O, Lindsay SW, Fillinger U. Pyriproxyfen for mosquito control: female sterilization or horizontal transfer to oviposition substrates by Anopheles gambiae sensu stricto and Culex quinquefasciatus. Parasit Vectors 2014; 7:280. [PMID: 24954695 PMCID: PMC4082483 DOI: 10.1186/1756-3305-7-280] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 06/16/2014] [Indexed: 11/10/2022] Open
Abstract
Background The use of gravid mosquitoes as vehicles to auto-disseminate larvicides was recently demonstrated for the transfer of pyriproxyfen (PPF) by container-breeding Aedes mosquitoes and presents an appealing idea to explore for other disease vectors. The success of this approach depends on the female’s behaviour, the time of exposure and the amount of PPF that can be carried by an individual. We explore the effect of PPF exposure at seven time points around blood feeding on individual Anopheles gambiae sensu stricto and Culex quinquefasciatus fecundity and ability to transfer in laboratory assays. Method Mosquitoes were exposed to 2.6 mg PPF per m2 at 48, 24 and 0.5 hours before and after a blood meal and on the day of egg-laying. The proportion of exposed females (N = 80-100) laying eggs, the number of eggs laid and hatched was studied. Transfer of PPF to oviposition cups was assessed by introducing 10 late instar insectary-reared An. gambiae s.s. larvae into all the cups and monitored for adult emergence inhibition. Results Exposure to PPF between 24 hours before and after a blood meal had significant sterilizing effects: females of both species were 6 times less likely (Odds ratio (OR) 0.16, 95% confidence interval (CI) 0.10-0.26) to lay eggs than unexposed females. Of the few eggs laid, the odds of an egg hatching was reduced 17 times (OR 0.06, 95% CI 0.04-0.08) in Anopheles but only 1.2 times (OR 0.82, 95% CI 0.73-0.93) in Culex. Adult emergence inhibition from larvae introduced in the oviposition cups was observed only from cups in which eggs were laid. When females were exposed to PPF close to egg laying they transferred enough PPF to reduce emergence by 65-71% (95% CI 62-74%). Conclusion PPF exposure within a day before and after blood feeding affects egg-development in An. gambiae s.s. and Cx. quinquefasciatus and presents a promising opportunity for integrated control of vectors and nuisance mosquitoes. However, sterilized females are unlikely to visit an oviposition site and therefore do not transfer lethal concentrations of PPF to aquatic habitats. This suggests that for successful auto-dissemination the optimum contamination time is close to oviposition.
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Affiliation(s)
| | | | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology (icipe), Thomas Odhiambo Campus, 40305 Mbita, Kenya.
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21
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Mdoe FP, Nkwengulila G, Chobu M, Lyaruu L, Gyunda IL, Mbepera S, Xue RD, Kweka EJ. Larvicidal effect of disinfectant soap on Anopheles gambiae s.s (Diptera: Culicidae) in laboratory and semifield environs. Parasit Vectors 2014; 7:211. [PMID: 24885903 PMCID: PMC4024623 DOI: 10.1186/1756-3305-7-211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 04/30/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mosquito larval control using chemicals and biological agents is of paramount importance in vector population and disease incidence reduction. A commercial synthetic disinfectant soap was evaluated against larvae of Anopheles gambiae s.s. in both laboratory and semi field conditions. METHOD Five concentrations of commercial synthetic disinfectant soap (0.0001, 0.001, 0.01, 0.1 and 1%) were prepared and evaluated against third instar larvae in laboratory and semi field environments. Mortality was scored at 12, 24, 48, and 72 hrs. Each dosage had 6 replicates, having twenty 3rd instar larvae of An.gambiae s.s. RESULTS In the laboratory phase, all dosages had significantly higher larval mortalities than in controls, while in semi field conditions, the dosages of 0.0001, 0.001 and 0.01% had lower mortalities than laboratory trials. In the comparison between semi field and laboratory trials, only 0.1 and 1% dosage had significant difference with more mortality in semifield conditions. Proportions of larvae that died during mortality monitoring intervals in laboratory and semi field had significant differences only at 12 hrs and 72 hrs. CONCLUSION The findings of this study have demonstrated that the mortality of larvae caused by commercial synthetic disinfectant soap is worth further studies in open water bodies. More studies are necessary to find out the effect of sunlight on the chemistry of the synthetic disinfectant and other variables in small scale full field trials.
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Affiliation(s)
- France P Mdoe
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar-es-salaam, P.O.Box 35165 Dar-es-salaam, Tanzania
| | - Gamba Nkwengulila
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar-es-salaam, P.O.Box 35165 Dar-es-salaam, Tanzania
| | - Mariam Chobu
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar-es-salaam, P.O.Box 35165 Dar-es-salaam, Tanzania
| | - Lucile Lyaruu
- Division of Livestock and Human Diseases Vector Control, Tropical Pesticides Research Institute, Ngaramtoni, Off Nairobi Road, P.O. Box 3024 Arusha, Tanzania
| | - Israel L Gyunda
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar-es-salaam, P.O.Box 35165 Dar-es-salaam, Tanzania
| | - Saada Mbepera
- Department of Zoology and Wildlife Conservation, College of Natural and Applied Sciences, University of Dar-es-salaam, P.O.Box 35165 Dar-es-salaam, Tanzania
| | - Rui-De Xue
- Anastasia Mosquito Control District, 500 Old Beach Road, St. Augustine, FL 32080, USA
| | - Eliningaya J Kweka
- Division of Livestock and Human Diseases Vector Control, Tropical Pesticides Research Institute, Ngaramtoni, Off Nairobi Road, P.O. Box 3024 Arusha, Tanzania
- Department of Medical Parasitology and Entomology, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania
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Gotifrid GM, Urasa FM, Katunzi G, Yarro JG, Munga S, Kweka EJ. Reduced hatchability of Anopheles gambiae s.s eggs in presence of third instar larvae. BMC Res Notes 2014; 7:231. [PMID: 24725618 PMCID: PMC3991882 DOI: 10.1186/1756-0500-7-231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 04/04/2014] [Indexed: 11/10/2022] Open
Abstract
Background We investigated the hatchability rates of freshly laid Anopheles gambiae s.s. eggs in presence of third instars larvae. These experiments were conducted using 30 eggs in larval densities of 20, 60 and 100 larvae in microcosms. These experiments were designed to evaluate the eggs hatchability in habitats with late larvae instars of the same species (experimental) or no larvae at all (control). Freshly laid eggs of An.gambiae s.s. were washed in microcosms containing larvae of third instars in different three densities (20, 60 and 100) and likewise in control microcosms (without larvae). Eggs hatchability was monitored twice daily until no more first instar larvae emerged. The numbers of first instars larvae were recorded daily and lost eggs were considered preyed upon by third instars. Findings The findings of this study showed that egg hatchability was significantly influenced by larval density. Conclusion The findings of this study suggest that presence of larvae in habitats may significantly reduce hatchability of eggs.
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Affiliation(s)
| | | | | | | | | | - Eliningaya J Kweka
- Division of Livestock and Human Diseases Vector Control, Mosquito Section, Tropical Pesticides Research Institute, P,O,Box 3024, Arusha, Tanzania.
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Gimonneau G, Brossette L, Mamaï W, Dabiré RK, Simard F. Larval competition between An. coluzzii and An. gambiae in insectary and semi-field conditions in Burkina Faso. Acta Trop 2014; 130:155-61. [PMID: 24269743 DOI: 10.1016/j.actatropica.2013.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 11/01/2013] [Accepted: 11/09/2013] [Indexed: 12/20/2022]
Abstract
Competition in mosquito larvae is common and different ecological context could change competitive advantage between species. Here, larval competition between the widely sympatric African malaria mosquitoes, Anopheles coluzzii and Anopheles gambiae were investigated in controlled insectary conditions using individuals from laboratory colonies and under ambient conditions using wild mosquitoes in a semi-field enclosure in western Burkina Faso. Larvae of both species were reared in trays at the same larval density and under the same feeding regimen in either single-species or mixed-species populations at varying species ratios reflecting 0%, 25%, 50% and 75% of competitor species. In the insectaries, where environmental variations are controlled, larvae of the An. coluzzii colony developed faster and with lower mortality than larvae of the An. gambiae colony (8.8±0.1 days and 21±3% mortality vs. 9.5±0.1 days and 32±3% mortality, respectively). Although there was no significant effect of competition on these phenotypic traits in any species, there was a significant trend for higher fitness of the An. coluzzii colony when competing with An. gambiae under laboratory conditions (i.e. lower development time and increased wing length at emergence, Cuzik's tests, P<0.05). In semi-field experiments, competition affected the life history traits of both species in a different way. Larvae of An. gambiae tended to reduce development time when in competition with An. coluzzii (Cuzick's test, P=0.002) with no impact either on mortality or size at emergence. On the other hand, An. coluzzii showed a significant trend for reduced larval mortality with increasing competition pressure (Cuzick's test, P=0.037) and production of smaller females when grown together with An. gambiae (Cuzick's test, P=0.002). Our results hence revealed that competitive interactions between larvae of the two species are context dependent. They further call for caution when exploring ecological processes using inbred laboratory colonies in this system of utmost medical importance.
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Affiliation(s)
- Geoffrey Gimonneau
- Institut de Recherche pour le Développement (IRD), UMR 224-CNRS 5290-Université de Montpellier 1-Université de Montpellier 2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France; Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest (DRO), 399 Avenue de la Liberté, 01 BP 545 Bobo Dioulasso, Burkina Faso.
| | - Lou Brossette
- Institut de Recherche pour le Développement (IRD), UMR 224-CNRS 5290-Université de Montpellier 1-Université de Montpellier 2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France.
| | - Wadaka Mamaï
- Institut de Recherche pour le Développement (IRD), UMR 224-CNRS 5290-Université de Montpellier 1-Université de Montpellier 2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France; Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest (DRO), 399 Avenue de la Liberté, 01 BP 545 Bobo Dioulasso, Burkina Faso.
| | - Roch K Dabiré
- Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest (DRO), 399 Avenue de la Liberté, 01 BP 545 Bobo Dioulasso, Burkina Faso.
| | - Frédéric Simard
- Institut de Recherche pour le Développement (IRD), UMR 224-CNRS 5290-Université de Montpellier 1-Université de Montpellier 2 MIVEGEC (Maladies Infectieuses et Vecteurs: Ecologie, Genetique, Evolution et Contrôle), team BEES (Biology, Ecology and Evolution of vector Systems), 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France; Institut de Recherche en Sciences de la Santé (IRSS), Direction Régionale de l'Ouest (DRO), 399 Avenue de la Liberté, 01 BP 545 Bobo Dioulasso, Burkina Faso.
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Gilbreath TM, Kweka EJ, Afrane YA, Githeko AK, Yan G. Evaluating larval mosquito resource partitioning in western Kenya using stable isotopes of carbon and nitrogen. Parasit Vectors 2013; 6:353. [PMID: 24330747 PMCID: PMC3866463 DOI: 10.1186/1756-3305-6-353] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 12/02/2013] [Indexed: 11/23/2022] Open
Abstract
Background In sub-Saharan Africa, malaria, transmitted by the Anopheles mosquito, remains one of the foremost public health concerns. Anopheles gambiae, the primary malaria vector in sub-Saharan Africa, is typically associated with ephemeral, sunlit habitats; however, An. gambiae larvae often share these habitats with other anophelines along with other disease-transmitting and benign mosquito species. Resource limitations within habitats can constrain larval density and development, and this drives competitive interactions among and between species. Methods We used naturally occurring stable isotope ratios of carbon and nitrogen to identify resource partitioning among co-occurring larval species in microcosms and natural habitats in western Kenya. We used two and three source mixing models to estimate resource utilization (i.e. bacteria, algae, organic matter) by larvae. Results Laboratory experiments revealed larval δ13C and δ15N composition to reflect the food sources they were reared on. Resource partitioning was demonstrated between An. gambiae and Culex quinquefasciatus larvae sharing the same microcosms. Differences in larval δ13C and δ15N content was also evident in natural habitats, and Anopheles species were consistently more enriched in δ13C when compared to culicine larvae. Conclusions These observations demonstrate inter-specific resource partitioning between Cx. quinquefasciatus and An. gambiae larvae in natural habitats in western Kenya. This information may be translated into opportunities for targeted larval control efforts by limiting specific larval food resources, or through bio-control utilizing competitors at the same trophic level.
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Affiliation(s)
| | | | | | | | - Guiyun Yan
- Program in Public Health, University of California, Irvine, CA 92697, USA.
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25
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Porretta D, Mastrantonio V, Amendolia S, Gaiarsa S, Epis S, Genchi C, Bandi C, Otranto D, Urbanelli S. Effects of global changes on the climatic niche of the tick Ixodes ricinus inferred by species distribution modelling. Parasit Vectors 2013; 6:271. [PMID: 24330500 PMCID: PMC3848450 DOI: 10.1186/1756-3305-6-271] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 09/12/2013] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Global climate change can seriously impact on the epidemiological dynamics of vector-borne diseases. In this study we investigated how future climatic changes could affect the climatic niche of Ixodes ricinus (Acari, Ixodida), among the most important vectors of pathogens of medical and veterinary concern in Europe. METHODS Species Distribution Modelling (SDM) was used to reconstruct the climatic niche of I. ricinus, and to project it into the future conditions for 2050 and 2080, under two scenarios: a continuous human demographic growth and a severe increase of gas emissions (scenario A2), and a scenario that proposes lower human demographic growth than A2, and a more sustainable gas emissions (scenario B2). Models were reconstructed using the algorithm of "maximum entropy", as implemented in the software Maxent 3.3.3e; 4,544 occurrence points and 15 bioclimatic variables were used. RESULTS In both scenarios an increase of climatic niche of about two times greater than the current area was predicted as well as a higher climatic suitability under the scenario B2 than A2. Such an increase occurred both in a latitudinal and longitudinal way, including northern Eurasian regions (e.g. Sweden and Russia), that were previously unsuitable for the species. CONCLUSIONS Our models are congruent with the predictions of range expansion already observed in I. ricinus at a regional scale and provide a qualitative and quantitative assessment of the future climatically suitable areas for I. ricinus at a continental scale. Although the use of SDM at a higher resolution should be integrated by a more refined analysis of further abiotic and biotic data, the results presented here suggest that under future climatic scenarios most of the current distribution area of I. ricinus could remain suitable and significantly increase at a continental geographic scale. Therefore disease outbreaks of pathogens transmitted by this tick species could emerge in previous non-endemic geographic areas. Further studies will implement and refine present data toward a better understanding of the risk represented by I. ricinus to human health.
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Affiliation(s)
- Daniele Porretta
- Department of Environmental Biology, University of Rome “La Sapienza”, Via dei Sardi 70, 00185 Rome, Italy
| | - Valentina Mastrantonio
- Department of Environmental Biology, University of Rome “La Sapienza”, Via dei Sardi 70, 00185 Rome, Italy
| | - Sara Amendolia
- Department of Environmental Biology, University of Rome “La Sapienza”, Via dei Sardi 70, 00185 Rome, Italy
| | - Stefano Gaiarsa
- Department of Veterinary Science and Public Health, University of Milan, Milan, Italy
| | - Sara Epis
- Department of Veterinary Science and Public Health, University of Milan, Milan, Italy
- School of Bioscience and Biotechnology, University of Camerino, Camerino, Italy
| | - Claudio Genchi
- Department of Veterinary Science and Public Health, University of Milan, Milan, Italy
| | - Claudio Bandi
- Department of Veterinary Science and Public Health, University of Milan, Milan, Italy
| | - Domenico Otranto
- Department of Veterinary Medicine, University of Bari, Bari, Italy
| | - Sandra Urbanelli
- Department of Environmental Biology, University of Rome “La Sapienza”, Via dei Sardi 70, 00185 Rome, Italy
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26
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Lunde TM, Korecha D, Loha E, Sorteberg A, Lindtjørn B. A dynamic model of some malaria-transmitting anopheline mosquitoes of the Afrotropical region. I. Model description and sensitivity analysis. Malar J 2013; 12:28. [PMID: 23342980 PMCID: PMC3664083 DOI: 10.1186/1475-2875-12-28] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 01/07/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Most of the current biophysical models designed to address the large-scale distribution of malaria assume that transmission of the disease is independent of the vector involved. Another common assumption in these type of model is that the mortality rate of mosquitoes is constant over their life span and that their dispersion is negligible. Mosquito models are important in the prediction of malaria and hence there is a need for a realistic representation of the vectors involved. RESULTS We construct a biophysical model including two competing species, Anopheles gambiae s.s. and Anopheles arabiensis. Sensitivity analysis highlight the importance of relative humidity and mosquito size, the initial conditions and dispersion, and a rarely used parameter, the probability of finding blood. We also show that the assumption of exponential mortality of adult mosquitoes does not match the observed data, and suggest that an age dimension can overcome this problem. CONCLUSIONS This study highlights some of the assumptions commonly used when constructing mosquito-malaria models and presents a realistic model of An. gambiae s.s. and An. arabiensis and their interaction. This new mosquito model, OMaWa, can improve our understanding of the dynamics of these vectors, which in turn can be used to understand the dynamics of malaria.
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Affiliation(s)
- Torleif Markussen Lunde
- Centre for International Health, University of Bergen, Bergen, Norway
- Bjerknes Centre for Climate Research, University of Bergen/Uni Research, Bergen, Norway
- Geophysical Institute, University of Bergen, Bergen, Norway
| | - Diriba Korecha
- National Meteorological Agency of Ethiopia, Addis Ababa, Ethiopia
- Geophysical Institute, University of Bergen, Bergen, Norway
| | | | - Asgeir Sorteberg
- Bjerknes Centre for Climate Research, University of Bergen/Uni Research, Bergen, Norway
- Geophysical Institute, University of Bergen, Bergen, Norway
| | - Bernt Lindtjørn
- Centre for International Health, University of Bergen, Bergen, Norway
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Lunde TM, Bayoh MN, Lindtjørn B. How malaria models relate temperature to malaria transmission. Parasit Vectors 2013; 6:20. [PMID: 23332015 PMCID: PMC3598736 DOI: 10.1186/1756-3305-6-20] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 01/15/2013] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND It is well known that temperature has a major influence on the transmission of malaria parasites to their hosts. However, mathematical models do not always agree about the way in which temperature affects malaria transmission. METHODS In this study, we compared six temperature dependent mortality models for the malaria vector Anopheles gambiae sensu stricto. The evaluation is based on a comparison between the models, and observations from semi-field and laboratory settings. RESULTS Our results show how different mortality calculations can influence the predicted dynamics of malaria transmission. CONCLUSIONS With global warming a reality, the projected changes in malaria transmission will depend on which mortality model is used to make such predictions.
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Affiliation(s)
- Torleif Markussen Lunde
- Bjerknes Centre for Climate Research, University of Bergen, Norway
- Centre for International Health, University of Bergen, Norway
- Bjerknes Centre for Climate Research, Uni Research, Norway
| | | | - Bernt Lindtjørn
- Centre for International Health, University of Bergen, Norway
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Tene Fossog B, Antonio-Nkondjio C, Kengne P, Njiokou F, Besansky NJ, Costantini C. Physiological correlates of ecological divergence along an urbanization gradient: differential tolerance to ammonia among molecular forms of the malaria mosquito Anopheles gambiae. BMC Ecol 2013; 13:1. [PMID: 23294940 PMCID: PMC3548750 DOI: 10.1186/1472-6785-13-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 12/27/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Limitations in the ability of organisms to tolerate environmental stressors affect their fundamental ecological niche and constrain their distribution to specific habitats. Evolution of tolerance, therefore, can engender ecological niche dynamics. Forest populations of the afro-tropical malaria mosquito Anopheles gambiae have been shown to adapt to historically unsuitable larval habitats polluted with decaying organic matter that are found in densely populated urban agglomerates of Cameroon. This process has resulted in niche expansion from rural to urban environments that is associated with cryptic speciation and ecological divergence of two evolutionarily significant units within this taxon, the molecular forms M and S, among which reproductive isolation is significant but still incomplete. Habitat segregation between the two forms results in a mosaic distribution of clinally parapatric patches, with the M form predominating in the centre of urban agglomerates and the S form in the surrounding rural localities. We hypothesized that development of tolerance to nitrogenous pollutants derived from the decomposition of organic matter, among which ammonia is the most toxic to aquatic organisms, may affect this pattern of distribution and process of niche expansion by the M form. RESULTS Acute toxicity bioassays indicated that populations of the two molecular forms occurring at the extremes of an urbanization gradient in Yaounde, the capital of Cameroon, differed in their response to ammonia. The regression lines best describing the dose-mortality profile differed in the scale of the explanatory variable (ammonia concentration log-transformed for the S form and linear for the M form), and in slope (steeper for the S form and shallower for the M form). These features reflected differences in the frequency distribution of individual tolerance thresholds in the two populations as assessed by probit analysis, with the M form exhibiting a greater mean and variance compared to the S form. CONCLUSIONS In agreement with expectations based on the pattern of habitat partitioning and exposure to ammonia in larval habitats in Yaounde, the M form showed greater tolerance to ammonia compared to the S form. This trait may be part of the physiological machinery allowing forest populations of the M form to colonize polluted larval habitats, which is at the heart of its niche expansion in densely populated human settlements in Cameroon.
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Affiliation(s)
- Billy Tene Fossog
- Institut de Recherche pour le Développement (IRD), Unité Mixte de Recherche MIVEGEC (UM1, UM2, CNRS 5290, IRD 224), Montpellier, France
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaounde, Cameroon
- Faculty of Sciences, University of Yaounde I, Yaounde, Cameroon
| | - Christophe Antonio-Nkondjio
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaounde, Cameroon
| | - Pierre Kengne
- Institut de Recherche pour le Développement (IRD), Unité Mixte de Recherche MIVEGEC (UM1, UM2, CNRS 5290, IRD 224), Montpellier, France
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaounde, Cameroon
| | - Flobert Njiokou
- Faculty of Sciences, University of Yaounde I, Yaounde, Cameroon
| | - Nora J Besansky
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
| | - Carlo Costantini
- Institut de Recherche pour le Développement (IRD), Unité Mixte de Recherche MIVEGEC (UM1, UM2, CNRS 5290, IRD 224), Montpellier, France
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaounde, Cameroon
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