Taxonomic assessment of phlebotomine sand flies in Southeast Asia based on records from Cambodia.

Previously considered a leishmaniasis-free region, Southeast Asia has reported emerging cases over the past 20 years. This has renewed interest in the primary vectors, the phlebotomine sand flies. However, information on these vectors in Southeast Asia, particularly in Cambodia, remains scarce. To update distribution records and assess species diversity, CDC light traps were deployed to collect sand flies at 16 locations across several provinces of Cambodia in 2011 and 2014. A total of 940 sand flies were collected and identified both morphologically and molecularly using cytochrome b as a marker gene. Species identification revealed the presence of four genera and 10 species. The predominant species was Grassomyia sp. (21.9%), followed by Sergentomyia sylvatica (21.4%) and Sergentomyia iyengari Group (16.7%). Generally identified as Grassomyia indica, the Grassomyia specimens found in this study exhibited morphological disparities, although genetic analysis showed homogeneity with Gr. indica from other countries. Sergentomyia iyengari and Sergentomyia barraudi each displayed two distinct groups based on both morphological and genetic analyses, suggesting that different species within these complexes are present in Cambodia. Further investigation of these species complexes is warranted, since genomic evidence suggests the existence of previously undescribed species in this region.