Peri-urban Cutaneous Leishmaniasis Transmission Dynamics with Regard to Associated Risk Factors in Mt. Elgon Focus, Kenya

Abstract

The cutaneous leishmaniasis infection status caused by Leishmania aethiopica and the vector sand flies distribution in relation to risk factors were investigated in the sites of Bungoma and Trans-Nzoia counties of Mt. Elgon region. These sites are allopatric. The sand flies Collections from the sites were carried out for five nights of each month using Center for Disease Control (CDC) light traps. Mean monthly data of ambient temperature, rainfall, and relative humidity in the two Counties were recorded during the 2015 study period. These data was obtained from Kimilili and Kitale weather stations of Bungoma and Trans-Nzoia study sites respectively. Soil temperatures were recorded monthly in the study sites. Thirty four patients clinically suspected of the disease were tested through microscopic examination for the presence of amastigote forms in their tissue biopsies upon signing the consent form. 657 sand fly specimens were collected. In the two sites, both homesteads and caves where sand flies were trapped only Phlebotomus pedifer were found. Sand fly abundance was negatively correlated with soil temperature, rainfall and relative humidity. The variation of case age-groups and the fact that all the cases were found in peri-urban areas suggests that there is an active transmission going on with Phlebotomus pedifer as the only vector in all the allopatric areas studied. It can also be concluded that like Phlebotomus papatasi, Phlebotomus pedifer can also cause transmission away from rural areas. Basing on the results of this research, it is recommended that People should not enter the caves since unprotected to avoid infection. Furthermore, the actual reservoir host within the peri-urban study sites needs to be investigated.