Bionomics and distribution of malaria vectors in Kisumu city, Western Kenya: implications for urban malaria transmission
Abstract Background Increasing unplanned urbanization in tropical Africa may create new niches for malaria vectors, raising transmission risk, yet control efforts focus on rural ecosystems. Understanding mosquito diversity, ecology and biting behaviour in urban areas is crucial for effective control...
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BMC
2025-03-01
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| Series: | Malaria Journal |
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| Online Access: | https://doi.org/10.1186/s12936-025-05332-7 |
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| author | Maxwell G. Machani Shirley A. Onyango Irene Nzioki Sylvia Milanoi Godfrey Nattoh John Githure Harrysone Atieli Chloe Wang Ming-Chieh Lee Goufa Zhou Andrew K. Githeko Yaw A. Afrane Eric Ochomo Guiyun Yan |
| author_facet | Maxwell G. Machani Shirley A. Onyango Irene Nzioki Sylvia Milanoi Godfrey Nattoh John Githure Harrysone Atieli Chloe Wang Ming-Chieh Lee Goufa Zhou Andrew K. Githeko Yaw A. Afrane Eric Ochomo Guiyun Yan |
| author_sort | Maxwell G. Machani |
| collection | DOAJ |
| description | Abstract Background Increasing unplanned urbanization in tropical Africa may create new niches for malaria vectors, raising transmission risk, yet control efforts focus on rural ecosystems. Understanding mosquito diversity, ecology and biting behaviour in urban areas is crucial for effective control. This study assessed Anopheles diversity, abundance, behaviour, and Plasmodium infection rates in Kisumu city, Kenya. Methods Indoor and outdoor host-seeking and resting adult mosquitoes were collected using CDC miniature light traps (CDC-LT) and Prokopack aspirators along an urban–rural transect. Anophelines were identified morphologically, with Anopheles gambiae sensu lato (s.l.) and Anopheles funestus group further distinguished to siblings using polymerase chain reaction (PCR). Sporozoite infection rates were determined using a multiplexed real-time quantitative PCR (qPCR) assay. Results A total of 3,394 female Anopheles mosquitoes were collected: An. gambiae s.l. (68%), An. funestus s.l. (19.8%), Anopheles coustani (7.8%), Anopheles pharoensis (2.6%), Anopheles maculipalipis (1.6%), and Anopheles leesoni (0.2%). All six species were found in urban zone, but only three were in peri-urban and rural sites. Overall, urban collection accounted for 55.5% of mosquitoes, followed by peri-urban (30%) and rural sites (14.5%). Anopheles arabiensis dominated urban (84.3%) and peri-urban (89%) sites, while An. gambiae sensu stricto (s.s.) was predominant in rural zone (60.2%) alongside An. arabiensis (39.7%). Anopheles funestus was predominant in peri-urban (98.4%) and rural (85.7%) areas, while An. leesoni accounted for 1.6% and 14.3%, respectively. In urban areas, all An. funestus s.l. samples were An. funestus s.s. . Most (55.5%) of Anopheles mosquitoes were collected indoors, while secondary vectors were mainly outdoors. Overall, sporozoite rates were higher outdoors (3.5%) than indoors (1.45%) in rural areas. Indoor rates were 2.5% (An. funestus), 1.4% (An. gambiae s.s.), and 1% (An. arabiensis). Outdoors, An. gambiae had 5.3%, and An. arabiensis 2.1%. In peri-urban areas, An. gambiae had 2.3%. No sporozoites were found in urban samples. Conclusion The study highlights a shift in Anopheles diversity towards urban areas with increased outdoor activity and outdoor malaria transmission in rural and peri-urban areas, underscoring the need for tools targeting outdoor-biting mosquitoes. The presence of An. funestus in urban settings emphasizes the need for sustained entomological surveillance to inform integrated vector control. |
| format | Article |
| id | doaj-art-3c8d341ae6044203a0859ff02c75d82e |
| institution | DOAJ |
| issn | 1475-2875 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | BMC |
| record_format | Article |
| series | Malaria Journal |
| spelling | doaj-art-3c8d341ae6044203a0859ff02c75d82e2025-08-20T03:01:42ZengBMCMalaria Journal1475-28752025-03-0124111210.1186/s12936-025-05332-7Bionomics and distribution of malaria vectors in Kisumu city, Western Kenya: implications for urban malaria transmissionMaxwell G. Machani0Shirley A. Onyango1Irene Nzioki2Sylvia Milanoi3Godfrey Nattoh4John Githure5Harrysone Atieli6Chloe Wang7Ming-Chieh Lee8Goufa Zhou9Andrew K. Githeko10Yaw A. Afrane11Eric Ochomo12Guiyun Yan13Centre for Global Health Research, Kenya Medical Research InstituteSchool of Zoological Sciences, Kenyatta UniversityCentre for Global Health Research, Kenya Medical Research InstituteCentre for Global Health Research, Kenya Medical Research InstituteCentre for Global Health Research, Kenya Medical Research InstituteInternational Center of Excellence for Malaria Research, Tom Mboya UniversityInternational Center of Excellence for Malaria Research, Tom Mboya UniversityProgram in Public Health, College of Health Sciences, University of CaliforniaProgram in Public Health, College of Health Sciences, University of CaliforniaProgram in Public Health, College of Health Sciences, University of CaliforniaCentre for Global Health Research, Kenya Medical Research InstituteDepartment of Medical Microbiology, College of Health Sciences, University of Ghana Medical School, University of GhanaCentre for Global Health Research, Kenya Medical Research InstituteProgram in Public Health, College of Health Sciences, University of CaliforniaAbstract Background Increasing unplanned urbanization in tropical Africa may create new niches for malaria vectors, raising transmission risk, yet control efforts focus on rural ecosystems. Understanding mosquito diversity, ecology and biting behaviour in urban areas is crucial for effective control. This study assessed Anopheles diversity, abundance, behaviour, and Plasmodium infection rates in Kisumu city, Kenya. Methods Indoor and outdoor host-seeking and resting adult mosquitoes were collected using CDC miniature light traps (CDC-LT) and Prokopack aspirators along an urban–rural transect. Anophelines were identified morphologically, with Anopheles gambiae sensu lato (s.l.) and Anopheles funestus group further distinguished to siblings using polymerase chain reaction (PCR). Sporozoite infection rates were determined using a multiplexed real-time quantitative PCR (qPCR) assay. Results A total of 3,394 female Anopheles mosquitoes were collected: An. gambiae s.l. (68%), An. funestus s.l. (19.8%), Anopheles coustani (7.8%), Anopheles pharoensis (2.6%), Anopheles maculipalipis (1.6%), and Anopheles leesoni (0.2%). All six species were found in urban zone, but only three were in peri-urban and rural sites. Overall, urban collection accounted for 55.5% of mosquitoes, followed by peri-urban (30%) and rural sites (14.5%). Anopheles arabiensis dominated urban (84.3%) and peri-urban (89%) sites, while An. gambiae sensu stricto (s.s.) was predominant in rural zone (60.2%) alongside An. arabiensis (39.7%). Anopheles funestus was predominant in peri-urban (98.4%) and rural (85.7%) areas, while An. leesoni accounted for 1.6% and 14.3%, respectively. In urban areas, all An. funestus s.l. samples were An. funestus s.s. . Most (55.5%) of Anopheles mosquitoes were collected indoors, while secondary vectors were mainly outdoors. Overall, sporozoite rates were higher outdoors (3.5%) than indoors (1.45%) in rural areas. Indoor rates were 2.5% (An. funestus), 1.4% (An. gambiae s.s.), and 1% (An. arabiensis). Outdoors, An. gambiae had 5.3%, and An. arabiensis 2.1%. In peri-urban areas, An. gambiae had 2.3%. No sporozoites were found in urban samples. Conclusion The study highlights a shift in Anopheles diversity towards urban areas with increased outdoor activity and outdoor malaria transmission in rural and peri-urban areas, underscoring the need for tools targeting outdoor-biting mosquitoes. The presence of An. funestus in urban settings emphasizes the need for sustained entomological surveillance to inform integrated vector control.https://doi.org/10.1186/s12936-025-05332-7AnophelesMalariaAnopheles densitySpecies compositionSporozoite infectionUrban city |
| spellingShingle | Maxwell G. Machani Shirley A. Onyango Irene Nzioki Sylvia Milanoi Godfrey Nattoh John Githure Harrysone Atieli Chloe Wang Ming-Chieh Lee Goufa Zhou Andrew K. Githeko Yaw A. Afrane Eric Ochomo Guiyun Yan Bionomics and distribution of malaria vectors in Kisumu city, Western Kenya: implications for urban malaria transmission Malaria Journal Anopheles Malaria Anopheles density Species composition Sporozoite infection Urban city |
| title | Bionomics and distribution of malaria vectors in Kisumu city, Western Kenya: implications for urban malaria transmission |
| title_full | Bionomics and distribution of malaria vectors in Kisumu city, Western Kenya: implications for urban malaria transmission |
| title_fullStr | Bionomics and distribution of malaria vectors in Kisumu city, Western Kenya: implications for urban malaria transmission |
| title_full_unstemmed | Bionomics and distribution of malaria vectors in Kisumu city, Western Kenya: implications for urban malaria transmission |
| title_short | Bionomics and distribution of malaria vectors in Kisumu city, Western Kenya: implications for urban malaria transmission |
| title_sort | bionomics and distribution of malaria vectors in kisumu city western kenya implications for urban malaria transmission |
| topic | Anopheles Malaria Anopheles density Species composition Sporozoite infection Urban city |
| url | https://doi.org/10.1186/s12936-025-05332-7 |
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