Ecological interactions of sand flies, hosts, and Leishmania panamensis in an endemic area of cutaneous leishmaniasis in Colombia.

Background: The transmission dynamics of leishmaniasis are complex. There is also a lack of information about the ecological relationships between the vector/host/parasite at a more local and specific level. The Andean region concentrates more than 50% of Colombia's cutaneous leishmaniasis (CL) cases. The study of the ecological interactions of sand flies through the identification of blood sources has provided information on the female's opportunistic behavior, feeding on various hosts. Therefore, this study aimed to determine sand flies' ecological interactions with Leishmania parasites and their blood sources in an endemic area of CL. Results: A total of 4,621 sand flies were collected, comprising 20 species, in which the most abundant were Nyssomyia yuilli yuilli (55.4%), Psychodopygus ayrozai (14.5%) and Ps. panamensis (13.4%). Sequences of 12S gene fragment were analyzed using the BLASTn search tool. Blood-meal source identification was successfully performed for 47 sand flies, detecting seven vertebrate species, human and armadillo being the most frequent. Leishmania DNA was amplified in four female pools, constituted by Ny. yuilli yuilli and Ps. ayrozai, and the identification through RFLP detected Leishmania (Viannia) panamensis in the positive pools. Conclusions: The interactions between the sand fly species, local mammalian fauna and the Leishmania parasite in this active focus of CL, provide evidence of the potential role of two different species in the maintenance of the parasite transmission, important information for the understanding of the ecoepidemiology and transmission dynamics of the disease in Andean endemic areas. However its necessary further evaluations of the vector and host competence in the transmission and maintenance of Leishmania spp, in these complex and diverse areas. Author summary: The transmission dynamics of leishmaniasis are complex due to the variety of sand fly species, parasites and hosts involved. Although Colombia is considered an endemic country for the disease, the biology, ecology, and identification of blood-feeding sources of sand flies in some endemic areas remain unexplored. For this reason, this study aimed to analyze parameters related to the ecological interactions of the elements of the transmission cycle of cutaneous leishmaniasis. Interactions were detected through parasite and vertebrate DNA identification in sand flies collected intra- and peridomiciliary. Our findings show relevant information on distinct transmission patterns and the participation of different sand fly species in the maintenance of Leishmania panamensis in those environments, suggesting Nyssomyia yuilli yuilli as its primary vector and Psychodopygus ayrozai as a bridging species between wild and peridomiciliary cycle. [ABSTRACT FROM AUTHOR]