Publications
14 results found
Guerra CA, Reiner RC, Perkins TA, et al., 2014, A global assembly of adult female mosquito mark-release-recapture data to inform the control of mosquito-borne pathogens, PARASITES & VECTORS, Vol: 7, ISSN: 1756-3305
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- Citations: 83
O'Loughlin SM, Magesa S, Mbogo C, et al., 2014, Genomic Analyses of Three Malaria Vectors Reveals Extensive Shared Polymorphism but Contrasting Population Histories, MOLECULAR BIOLOGY AND EVOLUTION, Vol: 31, Pages: 889-902, ISSN: 0737-4038
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- Citations: 31
Midega J, Blight J, Lombardo F, et al., 2014, Discovery and characterization of two Nimrod superfamily members in Anopheles gambiae, Pathogens and Global Health, Vol: 107, Pages: 463-474, ISSN: 2047-7724
Anti-bacterial proteins in mosquitoes are known to play an important modulatory role on immune responses to infections with human pathogens including malaria parasites. In this study we characterized two members of the Anopheles gambiae Nimrod superfamily, namely AgNimB2 and AgEater. We confirm that current annotation of the An. gambiae genome incorrectly identifies AgNimB2 and AgEater as a single gene, AGAP009762. Through in silico and experimental approaches, it has been shown that AgNimB2 is a secreted protein that mediates phagocytosis of Staphylococcus aureus but not of Escherichia coli bacteria. We also reveal that this function does not involve a direct interaction of AgNimB2 with S. aureus. Therefore, AgNimB2 may act downstream of complement-like pathway activation, first requiring bacterial opsonization. In addition, it has been shown that AgNimB2 has an anti-Plasmodium effect. Conversely, AgEater is a membrane-bound protein that either functions redundantly or is dispensable for phagocytosis of E. coli or S. aureus. Our study provides insights into the role of members of the complex Nimrod superfamily in An. gambiae, the most important African vector of human malaria.
Midega J, Smith D, Olotu A, et al., 2013, WIND DIRECTION AND PROXIMITY TO LARVAL SITES DETERMINES MALARIA RISK IN KILIFI, KENYA, PATHOGENS AND GLOBAL HEALTH, Vol: 107, Pages: 446-447, ISSN: 2047-7724
Walker M, Winskill P, Basanez M-G, et al., 2013, Temporal and micro-spatial heterogeneity in the distribution of Anopheles vectors of malaria along the Kenyan coast, PARASITES & VECTORS, Vol: 6, ISSN: 1756-3305
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- Citations: 23
Mwangangi JM, Muturi EJ, Muriu SM, et al., 2013, The role of Anopheles arabiensis and Anopheles coustani in indoor and outdoor malaria transmission in Taveta District, Kenya, PARASITES & VECTORS, Vol: 6, ISSN: 1756-3305
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- Citations: 62
Mwangangi JM, Mbogo CM, Orindi BO, et al., 2013, Shifts in malaria vector species composition and transmission dynamics along the Kenyan coast over the past 20 years., Malar J, Vol: 12
BACKGROUND: Over the past 20 years, numerous studies have investigated the ecology and behaviour of malaria vectors and Plasmodium falciparum malaria transmission on the coast of Kenya. Substantial progress has been made to control vector populations and reduce high malaria prevalence and severe disease. The goal of this paper was to examine trends over the past 20 years in Anopheles species composition, density, blood-feeding behaviour, and P. falciparum sporozoite transmission along the coast of Kenya. METHODS: Using data collected from 1990 to 2010, vector density, species composition, blood-feeding patterns, and malaria transmission intensity was examined along the Kenyan coast. Mosquitoes were identified to species, based on morphological characteristics and DNA extracted from Anopheles gambiae for amplification. Using negative binomial generalized estimating equations, mosquito abundance over the period were modelled while adjusting for season. A multiple logistic regression model was used to analyse the sporozoite rates. RESULTS: Results show that in some areas along the Kenyan coast, Anopheles arabiensis and Anopheles merus have replaced An. gambiae sensu stricto (s.s.) and Anopheles funestus as the major mosquito species. Further, there has been a shift from human to animal feeding for both An. gambiae sensu lato (s.l.) (99% to 16%) and An. funestus (100% to 3%), and P. falciparum sporozoite rates have significantly declined over the last 20 years, with the lowest sporozoite rates being observed in 2007 (0.19%) and 2008 (0.34%). There has been, on average, a significant reduction in the abundance of An. gambiae s.l. over the years (IRR = 0.94, 95% CI 0.90-0.98), with the density standing at low levels of an average 0.006 mosquitoes/house in the year 2010. CONCLUSION: Reductions in the densities of the major malaria vectors and a shift from human to animal feeding have contributed to the decreased burden of malaria along the Kenyan coast. Vecto
Midega JT, Smith DL, Olotu A, et al., 2012, Wind direction and proximity to larval sites determines malaria risk in Kilifi District in Kenya, NATURE COMMUNICATIONS, Vol: 3, ISSN: 2041-1723
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- Citations: 56
Mwangangi JM, Midega J, Kahindi S, et al., 2012, Mosquito species abundance and diversity in Malindi, Kenya and their potential implication in pathogen transmission., Parasitol Res, Vol: 110, Pages: 61-71
Mosquitoes (Diptera: Culicidae) are important vectors of human disease-causing pathogens. Mosquitoes are found both in rural and urban areas. Deteriorating infrastructure, poor access to health, water and sanitation services, increasing population density, and widespread poverty contribute to conditions that modify the environment, which directly influences the risk of disease within the urban and peri-urban ecosystem. The objective of this study was to evaluate the mosquito vector abundance and diversity in urban, peri-urban, and rural strata in Malindi along the Kenya coast. The study was conducted in the coastal district of Malindi between January and December 2005. Three strata were selected which were described as urban, peri-urban, and rural. Sampling was done during the wet and dry seasons. Sampling in the wet season was done in the months of April and June to cover the long rainy season and in November and December to cover the short rainy season, while the dry season was between January and March and September and October. Adult mosquito collection was done using Pyrethrum Spray Collection (PSC) and Centers for Disease Control and Prevention (CDC) light traps inside houses and specimens were identified morphologically. In the three strata (urban, peri-urban, and rural), 78.5% of the total mosquito (n = 7,775) were collected using PSC while 18.1% (n = 1,795) were collected using the CDC light traps. Using oviposition traps, mosquito eggs were collected and reared in the insectary which yielded 329 adults of which 83.8% (n = 276) were Aedes aegypti and 16.2% (n = 53) were Culex quinquefasciatus. The mosquito distribution in the three sites varied significantly in each collection site. Anopheles gambiae, Anopheles funestus and Anopheles coustani were predominant in the rural stratum while C. quinquefasciatus was mostly found in urban and peri-urban strata. However, using PSC and CDC light trap collection
Midega JT, Muturi EJ, Baliraine FN, et al., 2010, Population structure of Anopheles gambiae along the Kenyan coast, ACTA TROPICA, Vol: 114, Pages: 103-108, ISSN: 0001-706X
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- Citations: 10
Tun-Lin W, Lenhart A, Nam VS, et al., 2009, Reducing costs and operational constraints of dengue vector control by targeting productive breeding places: a multi-country non-inferiority cluster randomized trial., Trop Med Int Health, Vol: 14, Pages: 1143-1153
OBJECTIVES: To test the non-inferiority hypothesis that a vector control approach targeting only the most productive water container types gives the same or greater reduction of the vector population as a non-targeted approach in different ecological settings and to analyse whether the targeted intervention is less costly. METHODS: Cluster randomized trial in eight study sites (Venezuela, Mexico, Peru, Kenya, Thailand, Myanmar, Vietnam, Philippines), with each study area divided into 18-20 clusters (sectors or neighbourhoods) of approximately 50-100 households each. Using a baseline pupal-demographic survey, the most productive container types were identified which produced >or=55% of all Ae. aegypti pupae. Clusters were then paired based on similar pupae per person indices. One cluster from each pair was randomly allocated to receive the targeted vector control intervention; the other received the 'blanket' (non-targeted) intervention attempting to reach all water holding containers. RESULTS: The pupal-demographic baseline survey showed a large variation of productive container types across all study sites. In four sites the vector control interventions in both study arms were insecticidal and in the other four sites, non-insecticidal (environmental management and/or biological control methods). Both approaches were associated with a reduction of outcome indicators in the targeted and non-targeted intervention arm of the six study sites where the follow up study was conducted (PPI, Pupae per Person Index and BI, Breteau Index). Targeted interventions were as effective as non-targeted ones in terms of PPI. The direct costs per house reached were lower in targeted intervention clusters than in non-targeted intervention clusters with only one exception, where the targeted intervention was delivered through staff-intensive social mobilization. CONCLUSIONS: Targeting only the most productive water container types (roughly half of all water holding container types) wa
Kahindi SC, Midega JT, Mwangangi JM, et al., 2008, Efficacy of vectobac DT and culinexcombi against mosquito larvae in unused swimming pools in Malindi, Kenya., J Am Mosq Control Assoc, Vol: 24, Pages: 538-542, ISSN: 8756-971X
The efficacy and persistence of 2 bacterial larvicides, Vectobac-DT (Bacillus thuringiensis israelensis [Bti]) and CulinexCombi (Bti and Bacillus sphaericus [Bs]), were tested against Anopheles gambiae and Culex quinquefasciatus in temporarily unused swimming pools with rainwater in Malindi, Kenya. Pre- and posttreatment larval densities were recorded by sampling with the standard WHO dipping technique for 8 consecutive days. The larvicides were applied to the pools with a knapsack sprayer. The data showed that Vectobac-DT was highly effective against early instars of An. gambiae with 89% reduction within 24 h but not as effective against the early stages of Cx. quinquefasciatus with reduction of only 46%. CulinexCombi resulted in high mortalities to early instars of both species with over 97% reduction within 24 h, but showed a drastic reduction 48 h after application. Both Vectobac-DT and CulinexCombi were highly effective against late instars of both species, whereby Vectobac-DT persisted much longer than CulinexCombi. Anopheles gambiae was found to be more susceptible to both larvicides than Cx. quinquefasciatus. By their high efficacy and good persistence against mosquito larvae, both Vectobac-DT and CulinexCombi can be recommended for use in integrated mosquito control programs.
Midega JT, Mbogo CM, Mwnambi H, et al., 2007, Estimating dispersal and survival of Anopheles gambiae and Anopheles funestus along the Kenyan coast by using mark-release-recapture methods., J Med Entomol, Vol: 44, Pages: 923-929, ISSN: 0022-2585
Mark-release-recapture (MRR) experiments were conducted with emerging Anopheles gambiae s.l. and Anophelesfunestus Giles at Jaribuni and Mtepeni in Kilifi, along the Kenyan Coast. Of 739 and 1246 Anopheles released at Jaribuni and Mtepeni, 24.6 and 4.33% were recaptured, respectively. The daily survival probability was 0.96 for An. funestus and 0.95 for An. gambiae in Jaribuni and 0.83 and 0.95, respectively, in Mtepeni. The maximum flight distance recorded was 661 m. The high survival probability of An. gambiae and An. funestus estimated accounts for the continuous transmission of malaria along the Kenyan coast. This study also shows that the release of young, emergent female Anopheles improves the recapture rates and may be a better approach to MRR studies.
Midega JT, Nzovu J, Kahindi S, et al., 2006, Application of the pupal/demographic-survey methodology to identify the key container habitats of Aedes aegypti (L.) in Malindi district, Kenya., Ann Trop Med Parasitol, Vol: 100 Suppl 1, Pages: S61-S72, ISSN: 0003-4983
The pupal/demographic-survey methodology was evaluated in three coastal areas (one urban, one peri-urban and one rural) of Malindi district, Kenya, in attempts to identify the types of domestic container that are most productive for Aedes aegypti (L.) pupae. The results demonstrated the practicality and consistency of the methodology, as a tool both for identifying and guiding the targeted control of the most productive container habitats, and for determining the mean numbers of pupae/person, as measures of the risk of dengue transmission.Twenty-five types of container were identified indoors and 50 types outdoors. In total, only 4,178 pupae were seen indoors and 795 outdoors. Pupal productivity was dependent on the type, location and volume of the container and the season of the year. Metallic drums and jerricans contributed >70% of the pupae encountered indoors in the wet season whereas, in the rural area, plastic drums contributed 83.7% of all the larvae seen outdoors during the dry season. Container productivity was not consistent during the different surveys. The highest mean numbers of pupae/person (7.61) and of pupae/household (18.12) were recorded in the rural area.
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