Species diversity and vector competence of sand flies in an urban cycle of cutaneous leishmaniasis in Shiraz, Southwestern Iran

Objectives: Detailed entomological profiling, including species composition and natural infection rates, is crucial for understanding transmission dynamics and designing effective control strategies in these unique ecosystems. Materials and Methods: An integrated entomological survey was conducted in the historic urban district of Shiraz, southwestern Iran, during the 2024 active season. Sand flies were collected using a multi-method approach combining monthly deployment of adhesive traps, Centers for Disease Control miniature light traps, and manual aspiration from resting sites. Specimens were morphologically identified using taxonomic keys. A subset of female sand flies was analyzed for Leishmania infection via a nested polymerase chain reaction protocol targeting kinetoplast minicircle DNA. Results: A total of 435 sand flies were collected. Phlebotomus sergenti was the dominant species, constituting 53.6% of the fauna, followed by Phlebotomus papatasi (34.0%), Sergentomyia tiberiadis (7.1%), and Sergentomyia clydei (5.3%). Spatial distribution was significantly biased toward outdoor environments (68.5% of captures). Activity followed a unimodal seasonal pattern, with a peak in the hot summer months (August). Molecular analysis of 112 females revealed a Leishmania tropica infection rate of 14.3% (7/52) in P. sergenti . No Leishmania infections were detected in P. papatasi or Sergentomyia species. Conclusion: This study confirms P. sergenti as the predominant and competent vector of L. tropica in urban Shiraz. It’s marked by exophily and a distinct seasonal peak, highlighting critical vulnerabilities in the transmission cycle. These findings underscore the necessity of moving beyond broad interventions to develop spatially and temporally targeted vector control strategies that address the specific ecology of P. sergenti in historic urban landscapes.