Differences in malaria vector biting behavior and changing vulnerability to malaria transmission in contrasting ecosystems of western Kenya

Parasites & Vectors

Research

Andrew K. Githeko¹  Eric Ochomo¹  Maxwell G. Machani¹  Irene Nzioki²  Yaw A. Afrane³  Guiyun Yan⁴  Shirley A. Onyango⁵  Kevin K. Kabui⁵ 

[1] Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya;Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya;School of Zoological Sciences, Kenyatta University, Nairobi, Kenya;Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Accra, Ghana;Program in Public Health, College of Health Sciences, University of California, 92697, Irvine, CA, USA;School of Zoological Sciences, Kenyatta University, Nairobi, Kenya;

关键词: Malaria vectors;    Biting behavior;    Human behavior;    Western Kenya;   

DOI  :  10.1186/s13071-023-05944-5

 received in 2023-04-03, accepted in 2023-08-24,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundDesigning, implementing, and upscaling of effective malaria vector control strategies necessitates an understanding of when and where transmission occurs. This study assessed the biting patterns of potentially infectious malaria vectors at various hours, locations, and associated human behaviors in different ecological settings in western Kenya.MethodsHourly indoor and outdoor catches of human-biting mosquitoes were sampled from 19:00 to 07:00 for four consecutive nights in four houses per village. The human behavior study was conducted via questionnaire surveys and observations. Species within the Anopheles gambiae complex and Anopheles funestus group were distinguished by polymerase chain reaction (PCR) and the presence of Plasmodium falciparum circumsporozoite proteins (CSP) determined by enzyme-linked immunosorbent assay (ELISA).ResultsAltogether, 2037 adult female anophelines were collected comprising the An. funestus group (76.7%), An. gambiae sensu lato (22.8%), and Anopheles coustani (0.5%). PCR results revealed that Anopheles arabiensis constituted 80.5% and 79% of the An. gambiae s.l. samples analyzed from the lowland sites (Ahero and Kisian, respectively). Anopheles gambiae sensu stricto (hereafter An. gambiae) (98.1%) was the dominant species in the highland site (Kimaeti). All the An. funestus s.l. analyzed belonged to An. funestus s.s. (hereafter An. funestus). Indoor biting densities of An. gambiae s.l. and An. funestus exceeded the outdoor biting densities in all sites. The peak biting occurred in early morning between 04:30 and 06:30 in the lowlands for An. funestus both indoors and outdoors. In the highlands, the peak biting of An. gambiae occurred between 01:00 and 02:00 indoors. Over 50% of the study population stayed outdoors from 18:00 to 22:00 and woke up at 05:00, coinciding with the times when the highest numbers of vectors were collected. The sporozoite rate was higher in vectors collected outdoors, with An. funestus being the main malaria vector in the lowlands and An. gambiae in the highlands.ConclusionThis study shows heterogeneity of anopheline distribution, high outdoor malaria transmission, and early morning peak biting activity of An. funestus when humans are not protected bybednetsin the lowland sites. Additional vector control efforts targeting the behaviors of these vectors, such as the use of non-pyrethroids for indoor residual spraying and spatial repellents outdoors, are needed.Graphical Abstract

【 授权许可】

CC BY   
© BioMed Central Ltd., part of Springer Nature 2023

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