In northwestern Kenya, Turkana County has been historically considered unsuitable for stable malaria transmission because of its unfavorable climate and predominantly semi-nomadic population; consequently, it is overlooked during malaria control planning. However, the area is changing, with substantial development, an upsurge in travel associated with resource extraction, and more populated settlements forming. Recently, numerous malaria outbreaks have highlighted the need to characterize malaria transmission and its associated risk factors in the region to inform control strategies. Reactive case detection of confirmed malaria cases at six health facilities across central Turkana was conducted from 2018 to 2019. Infections in household members of index cases were detected by malaria rapid diagnostic tests (RDTs) and PCR tests, and they were grouped according household and individual characteristics. The relationships between putative risk factors and infection were quantified by multilevel logistic regression models. Of the 3,189 household members analyzed, 33.6% had positive RDT results and/or PCR test results. RDT-detected infections were more prevalent in children; however, PCR-detected infections were similarly prevalent across age groups. Recent travel was rarely reported and not significantly associated with infection. Bed net coverage was low and net crowding was associated with increased risks of household infections. Infections were present year-round, and fluctuations in prevalence were not associated with rainfall. These findings indicate year-round, endemic transmission with moderate population immunity. This is in stark contrast to recent estimates in this area. Therefore, further investigations to design effective intervention approaches to address malaria in this rapidly changing region and other similar settings across the Horn of Africa are warranted.
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Address correspondence to Hannah Meredith, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, E6003, Baltimore, MD 21205. E-mail: email@example.com
These authors contributed equally to this work.
Disclosure: Written informed consent was obtained from all participants. The study procedures were approved by the ethics review board of Moi University and Duke University. The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Financial support: This work was supported by the National Institutes of Allergy and Infectious Diseases of the National Institutes of Health (R21AI133013 to W. P. O.). A. W. is funded by a Career Award at the Scientific Interface by the Burroughs Wellcome Fund, and by the National Library of Medicine of the National Institutes of Health (DP2LM013102). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.