Mapping visceral leishmaniasis and examining environmental influences in Baringo County, Kenya

Visceral leishmaniasis (VL) is a highly debilitating parasitic disease that primarily affects people living in poverty. In northern Baringo County, Kenya, VL contributes greatly to the overall burden of disease. The aim of this study was to identify hotspots of VL transmission and regional environmental associations in this area. Data was obtained from Chemolingot Sub-County Hospital's laboratory records and VL prevalence was assessed at the sub-location level. Monthly environmental covariates-mean, maximum, and minimum temperature, total precipitation, relative humidity, normalized difference vegetation index (NDVI), and elevation-were retrieved from Google Earth Engine. Spatial clustering was assessed with Getis-Ord GI* hotspot analysis in ArcGIS Pro. VL prevalence were modelled at the sub-location level with negative binomial regression to identify environmental risk factors for transmission. Between July 2019 and December 2024, 637 confirmed cases translated to an overall period prevalence of 2.71 per 1000 residents across Tiaty East and West. Four sub-locations were identified as VL hotspots; Losikiriamoi recorded the highest prevalence, 43.4 per 1000. The final model after excluding collinear variables included mean monthly temperature, precipitation, elevation, and NDVI. Mean monthly temperature and precipitation were significantly associated with VL prevalence at the sub-location level. Elevation and NDVI were not significant predictors. These findings can inform targeted VL surveillance and control strategies, which is particularly important in a resource-limited field. Changes in temperature and precipitation should be monitored by local public health officials to anticipate changes in VL transmission.