An Atypical Case of Autochthonous Cutaneous Leishmaniasis Associated with Naturally Infected Phlebotomine Sand Flies in Texas, United States.

In the United States, phlebotomine sand flies carrying () are endemic along the southern border. However, relatively little is known about the enzootic and zoonotic transmission of () within the United States, and autochthonous cases of the consequent disease are rarely reported. We investigated an atypical case of cutaneous leishmaniasis (CL) caused by () in a patient from central Texas which did not respond to a typical antileishmanial chemotherapy. We also investigated sand fly vectors around the patient's residence. PCR followed by DNA sequencing was used for determination of spp., sand fly species, and host blood meal source. The . (.) genotype from the patient was identical to one found in a positive sand fly. Moreover, this genotype presented the same single-nucleotide polymorphisms as other historical CL cases acquired in Texas over the last 10 years, but distinct from those originating in Mexico and Central America. Three sand fly species were identified among the samples analyzed ( = 194), the majority of which were () ( = 190), of which four specimens tested positive for and two blood-fed specimens showed the presence of a human blood meal. This study highlights the complexity of clinical management of CL in a setting where the disease is infrequently encountered. The detection of human blood in . () is the first documentation of anthropophagy in this species. This is the first report of wild-caught, naturally infected sand flies found in association with an autochthonous case of human leishmaniasis and the specific strain of () in the United States.