Feeding behavior and activity of Phlebotomus pedifer and potential reservoir hosts of Leishmania aethiopica in southwestern Ethiopia

Background Cutaneous leishmaniasis (CL) is a major public health concern in Ethiopia. However, knowledge about the complex zoonotic transmission cycle is limited, hampering implementation of control strategies. We explored the feeding behavior and activity of the vector (Phlebotomus pedifer) and established the role of livestock in CL transmission.    Methods Blood meal origins of engorged sand flies were determined by sequencing host DNA. A host choice experiment was performed to assess the feeding preference of P. pedifer when humans and hyraxes are equally accessible. Ear and nose biopsies from goats and bovines were screened for the presence of Leishmania parasites. Sand flies were captured indoor and outdoor with human landing catches (HLC) and CDC light traps to determine at which time and where P. pedifer is mostly active.  Principal findings A total of 180 sand flies were found to bite hosts of 12 genera. Humans were the predominant blood meal source (59.4%, p < 0.001) in all habitats, even in caves, where hyraxes are abundant. Only 10.6% of the sand flies fed on hyraxes based on the blood meal analysis, but the host choice experiment revealed that sand flies have a significant preference for feeding on hyraxes over humans (p = 0.009) when hosts are equally accessible. Only a single goat nose biopsy from 412 animal samples was found with Leishmania RNA. We found that P. pedifer is predominantly endophagic (p = 0.003), but occurs both indoors and outdoors. A substantial amount of sand flies was active in the early evening, which increased over time reaching its maximum around midnight.  Conclusion We indicate that Leishmania transmission in southwestern Ethiopia is, in contrast to earlier suggestions, likely mainly anthroponotic and that livestock does not play a role in transmission. Combined indoor and outdoor vector control measures at night are required for efficient vector control.