First record of Phlebotomus sergenti (Diptera: Psychodidae) in China and its potential epidemiological implications

Leishmaniasis is a severe parasitic disease transmitted by sand fly bites. Phlebotomus sergenti is a principal vector of Leishmania tropica, causing anthroponotic cutaneous leishmaniasis (ACL) across the Mediterranean, North Africa, South Asia, and West Asia. The Xinjiang Uygur Autonomous Region, located in northwestern China, is a well-recognized endemic focus of visceral leishmaniasis (VL), with sporadic cutaneous leishmaniasis cases also documented in the region. Nevertheless, Ph. sergenti has never been reported in China prior to this study.

Field investigations were carried out in Artux City (July 2023) and Akto County (August-September 2024), Kizilsu Kirghiz Autonomous Prefecture, Xinjiang Uygur Autonomous Region. Sand flies were collected using light traps in livestock pens and residential areas. A total of 2,013 sand fly specimens were collected and 319 of them were identified through morphological examination of the pharynx, spermathecae, and genitalia, combined with molecular analysis of mitochondrial cytochrome c oxidase subunit I (COI) and cytochrome b (Cyt b) genes. Among the identified specimens, 145 specimens were identified as Ph. sergenti (36 from Artux City, 109 from Akto County), representing the first record of this species in China. Phylogenetic analysis based on COI and Cyt b sequences showed that Chinese Ph. sergenti populations clustered with those from neighboring countries (e.g., Afghanistan), with no significant genetic differentiation between the two sampling localities. Metagenomic screening of pooled samples revealed the presence of Wolbachia endosymbionts but no detection of Leishmania spp., Trypanosoma spp. or Bartonella spp. in the collected Ph. sergenti specimens.

This study represents the first confirmed record of Ph. sergenti in China, filling a critical gap in the distribution map of this medically important sand fly species. The occurrence of Ph. sergenti at the China-Kyrgyzstan border region suggests potential transboundary dispersal of this vector and underscores the need for enhanced surveillance and cross-border collaborative efforts to monitor the spread of leishmaniasis and other vector-borne diseases in Central Asia.