CHARACTERIZATION OF SANDFLY POTENTIAL VECTORS AND RESERVOIR HOSTS OF CUTANEOUS LEISHMANIASIS AND THEIR HABITATS IN BUNGOMA COUNTY, KENYA

Abstract

Cutaneous leishmaniasis (CL), a neglected tropical disease caused by Leishmania parasites and transmitted by sandfly vectors, is a significant health concern in Bungoma County, and other Kenyan leishmaniasis-endemic counties. The present study aimed to characterize the distribution and ecological attributes of habitats of sandfly vectors and reservoir hosts of CL. The research objectives included: determining sandfly species diversity and abundance in identified sandfly habitats, evaluating the effects of temperature, relative humidity, and altitude on sandfly occurrence, analyzing soil characteristics in sandfly habitats for their physical and chemical properties, determining the association of sandfly populations and plant species populations in the study area, and evaluating the relationship between potential vertebrate reservoir hosts populations and sandfly populations in the study area. Sandflies were collected from their habitats using CDC light traps, dissected and identified morphologically between January 2021 and December 2022. Species diversity and evenness was analyzed using the Shannon-Weinner’s diversity index. A total of 6,156 sandflies were captured, with Phlebotomus pedifer accounting for 94%, P. elgonensis 0.5%, and Sergentomyia species 5.5%of the collections. Environmental factors, including temperature (21– 29°C), relative humidity (75-90%) and altitude (1,506–3,100 masl), were significant (P < 0.05) determinants of sandfly distribution. The correlation between soil properties and sandfly abundance was non-significant. Plant species diversity index (3.14 H’) and vertebrate diversity index (2.06 H’) indicated strong association with sandfly abundance, highlighting ecological drivers of the vector populations. The study concluded that Phlebotomus pedifer is the dominant sandfly vector species of CL in Bungoma County; while it is the people who go to the vector habitats (caves) who get

bitten and become infected with CL. These findings underscore the need for habitat- specific interventions, such as environmental management to control sandfly

populations in caves to reduce the transmission of CL in the study area and other similar regions.