STATUS OF LEISHMANIA PARASITE SPECIES, SANDFLY VECTOR SPECIES AND RESERVOIR HOST SPECIES IN MT. ELGON, KENYA

Abstract

Leishmaniasis is a major public health problem experienced globally and is caused by parasite species of the genus Leishmania, transmitted through the bite of infected female phlebotomine sandfly. The current study determined natural infection of Leishmania species in sandfly vector and in reservoir hosts species inhabiting caves in Mount Elgon in Kenya. The study also determined bloodmeal sources for the sandflies. A total of 5,688 sandflies were collected using Center for Disease Control (CDC) light traps and analysed for Leishmania infectivity by microscopy and taxonomy by morphological and molecular characterization sequencing using Cytochrome c oxidase subunit 1 (COI). The vector species abundance was determined as quantitative counts per trap site was analysed by One Way ANOVA. Blood, liver and spleen smears were prepared from 199 bats and 25 hyraxes collected from the same caves and observed microscopically. The microscopy results showed Leishmania (amastigotes) in reservoir hosts’ macrophages, while some of the Leishmania parasites were observed extra-cellularly having been released from ruptured cells during preparation of the films/smears. In this study, bats belonging to five species were morphologically identified with significant differences in their parasite abundance between the species (χ2 = 16.7845, df = 7, P = 0.0002). The bat species had higher overall prevalence of the parasite infections compared to the hyraxes ((χ2 = 7.342, df. =1, p = 0.0043), with Cardioderma cor, Chaerephon pumilus and Rhinolophus clivosus having more than 5% prevalence of the Leishmania infections. Analysis of 200 blood fed sandflies by ELISA showed that 120(60%) fed on humans, 55(28%) fed on bats, 16(8%) fed on hyraxes and 9(5%) fed on cats. It was concluded that transmission of Leishmania parasites in the study area involved three wild reservoir hosts (bats, hyraxes and cats) and two vector species Phlebotomus pedifer and Phlebotomus elgonensis. This study demonstrated for the first time, the detection of L. major and L. tropica in P. pedifer sandflies from Mt. Elgon. This study suggests that disruption of the life cycle of the Leishmania parasites should be done targeting the phlebotomine vectors and the reservoir animals in the region. However, more studies are needed to get sufficient information on other factors influencing the transmission of Leishmania in the region to enable effective implementation of preventive and control measures.