Phlebotomine sand fly vector distribution, seasonality, blood meal sources, and infection rates in cutaneous leishmaniasis endemic areas of Northeast Ethiopia

Cutaneous leishmaniasis (CL) is a significant health problem in Northeast Ethiopia. Leishmania aethiopica was identified in Phlebotomus longipes sand flies 50 years ago. However, the current sand fly fauna, distribution, seasonality, host preference, and Leishmania infection rates remain poorly understood. This study investigated the sand fly vectors distribution, seasonality, blood meal sources, and Leishmania infection rates in the area. Sand fly vectors were collected via CDC light traps in four villages from February to July 2024, and Leishmania DNA and blood meal sources were identified using polymerase chain reaction (PCR). A total of 1,509 sand fly vectors were collected and identified morphologically using taxonomic keys. Phlebotomine sand flies were confirmed by molecular assays. The proportion of males and females varied significantly (χ² = 10.01, p = 0.018), and Phlebotomus longipes accounted for 97.3% (1,468/1,509) of the captures. The peak abundance occurred in June and July, with the potential for high CL transmission risk. Leishmania DNA was detected in P. longipes, with infection rates of 0.93%, 0.68%, and 0.40% in Kelina, Mergeja, and Laftota, respectively. Blood meal analysis revealed a preference for cattle (70.7%), followed by goats (16.3%) and humans (3.3%). The presence of Leishmania parasites in P. longipes suggests the role of this species in CL transmission. The detection of bovine, goat, and human blood meals indicates that P. longipes is opportunistic in its feeding behavior, depending on the availability of the host, with predominant for zoophilic tendencies. In general, this study highlights the need for continued entomological surveillance and further studies on P. longipes ecology and behavior to develop effective control strategies to reduce the burden of CL in the area.