Abstract / Summary
Abstract Background Phlebotomine sand flies (Diptera: Psychodidae) are the primary vectors of Leishmania parasites, the causative agents of leishmaniasis, one of the most important vector-borne diseases worldwide. In the eastern Mediterranean basin, Leishmania infantum is transmitted by several Phlebotomus species, including Phlebotomus perfiliewi , Phlebotomus tobbi , and Phlebotomus neglectus , although the identity and relative roles of vector species vary geographically and remain incompletely resolved. Multiple Leishmania species are endemic in Israel, and L. infantum causes both visceral and cutaneous leishmaniasis in humans, with dogs serving as the main reservoir. However, the precise sand fly vectors responsible for L. infantum transmission in different regions of the country remain uncertain, particularly regarding the role of Phlebotomus syriacus , a common species long suspected but never molecularly confirmed as a carrier. Methods Sand flies were collected using CDC miniature light traps in two endemic Israeli villages: Aderet (central) and Kahal (northern) between 2021 and 2023. Specimens were identified morphologically (males) and molecularly (females). Unfed and blood-fed females were screened for Leishmania DNA using real-time PCR–HRM targeting the ITS1 region, and blood-meal sources were identified through sequencing. Results 20,634 sand flies were collected, including 13,676 females (66.3%), of which 4635 samples representing 5050 females were analyzed. Fourteen sand fly species were identified. Larroussius species dominated, with Ph. syriacus prevalent in Aderet (27.5%), while Ph. galilaeus (54.1%) and Ph. tobbi (24.9%) predominated in Kahal. Three samples were positive for L. infantum DNA: two individual unfed female Ph. syriacus from Aderet, and one pooled sample from Kahal. These findings represent the first species-resolved detection of L. infantum DNA in Ph. syriacus in Israel and worldwide. Blood-meal analysis identified vertebrate hosts in 74.2% of engorged females, with strong dominance of cattle (84.8%), followed by canids (5.8%) and other mammals. Phlebotomus syriacus were found to feed on canids (16.7%), supporting its potential epidemiological relevance. Conclusions The study provides the first molecular evidence supporting Ph. syriacus as a putative vector of L. infantum in central Israel. The results indicate a heterogeneous transmission system with important implications for targeted surveillance and vector-focused control strategies.