Discovery of the vector of visceral leishmaniasis, () Sinton, 1928, in Kenya suggests complex transmission dynamics.

Visceral and cutaneous leishmaniasis are endemic to specific regions due to the ecological preferences of phlebotomine sand flies and spp. transmission. Sand fly entomological data in northern Kenya are scarce due to limited studies and neglect of leishmaniasis. The aim of this study was to investigate: (i) sand fly diversity and distribution; (ii) occurrence of DNA within sand flies; and (iii) blood-meal sources of sand flies in Laisamis, northern Kenya. We conducted an entomological survey during February and March of 2021 in five areas of Laisamis sub-county using standard CDC light traps. A total of 1009 sand flies (394 male and 615 female) were morphologically identified, and representative samples verified by PCR amplification and sequencing of the cytochrome oxidase subunit 1 (1) gene. Similarly, we identified blood-meal sources and DNA in female sand flies by PCR amplicon sequencing of the vertebrate () gene and internal transcribed spacer 1 (ITS1) of the 28S rRNA gene, respectively. (59.8%) was the most abundant sand fly species. Though collected mainly from one locality (Tirgamo), 14.8% of samples belonged to () Sinton, 1928. We detected DNA of in 5.19% of , whereas DNA was detected in (7.51%), (8.00%), and (8.33%). Nine of 13 blood-fed sand flies had obtained blood from humans, of which 33.3% had DNA. Both and primarily fed on humans and could potentially be involved in the transmission of cutaneous leishmaniasis. The findings of this study contribute to the understanding of sand fly vector populations and their potential to transmit leishmaniasis in the area.