Entomological survey of sand fly vectors and molecular screening for Leishmania parasite in refugee camps in Ethiopia

Visceral leishmaniasis is transmitted by infected female sand flies. However, entomological data from refugee camps remained limited. This study aimed to describe sand fly fauna and assess natural Leishmania infection in selected refugee camps in Ethiopia. The study was conducted in four refugee camps. Sand flies were collected using a CDC light trap and sticky trap. Both male and female sand flies were dissected, and morphologically identified. The female sand flies were preserved in 95% ethyl alcohol for Leishmania DNA screening. A total of 2196 sand flies were collected. Phlebotomus rodhaini, the only Phlebotomus species identified, accounted for 1.7% of the collections. Sergentomyia antennatus was the most abundant species (50.8%), followed by S. africanus (15.8%), S. schwetzi (14.3%), S. bedfordi (10.9%), S. clydei (5.2%), S. squamipleuris (1.2%), and S. adleri (0.1%). Species richness was highest in Terkidi camp, whereas overall diversity was greatest in Sherkole. Indoor collections were limited (< 2.3%), confirming predominantly exophilic resting behavior. Termite hills and peridomestic habitats harbored the highest sand fly densities. Polymerase chain reaction screening showed no evidence of Leishmania infection. This first entomological survey conducted in refugee camps in Ethiopia documents a sand fly fauna dominated by outdoor collections, a very low abundance of Ph. rodhaini, and no detectable Leishmania infection. These findings suggest the need for longitudinal monitoring to capture seasonal variation.