Altitude, not potential larval habitat availability, explains pronounced variation in Plasmodium falciparum infection prevalence in the western Kenya highlands.
Colins O Oduma, Maurice Ombok, Xingyuan Zhao, Tiffany Huwe, Bartholomew N Ondigo, James W Kazura, John Grieco, Nicole Achee, Fang Liu, Eric Ochomo, Cristian Koepfli
Author Information
Colins O Oduma: Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya.
Maurice Ombok: Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya.
Xingyuan Zhao: Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN, United States of America. ORCID
Tiffany Huwe: Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America. ORCID
Bartholomew N Ondigo: Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya.
James W Kazura: Case Western Reserve University, Center for Global Health and Diseases, Cleveland, OH, United States of America. ORCID
John Grieco: Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America.
Nicole Achee: Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America. ORCID
Fang Liu: Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN, United States of America.
Eric Ochomo: Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya.
Cristian Koepfli: Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, United States of America. ORCID
Progress in malaria control has stalled over the recent years. Knowledge on main drivers of transmission explaining small-scale variation in prevalence can inform targeted control measures. We collected finger-prick blood samples from 3061 individuals irrespective of clinical symptoms in 20 clusters in Busia in western Kenya and screened for Plasmodium falciparum parasites using qPCR and microscopy. Clusters spanned an altitude range of 207 meters (1077-1284 m). We mapped potential mosquito larval habitats and determined their number within 250 m of a household and distances to households using ArcMap. Across all clusters, P. falciparum parasites were detected in 49.8% (1524/3061) of individuals by qPCR and 19.5% (596/3061) by microscopy. Across the clusters, prevalence ranged from 26% to 70% by qPCR. Three to 34 larval habitats per cluster and 0-17 habitats within a 250m radius around households were observed. Using a generalized linear mixed effect model (GLMM), a 5% decrease in the odds of getting infected per each 10m increase in altitude was observed, while the number of larval habitats and their proximity to households were not statistically significant predictors for prevalence. Kitchen located indoors, open eaves, a lower level of education of the household head, older age, and being male were significantly associated with higher prevalence. Pronounced variation in prevalence at small scales was observed and needs to be taken into account for malaria surveillance and control. Potential larval habitat frequency had no direct impact on prevalence.
References
PLOS Glob Public Health. 2022 Jul 28;2(7):e0000828
[PMID: 36962426]
