Leishmaniasis in Texas: prevalence and seasonal transmission of Leishmania mexicana in Neotoma micropus.

The annual prevalence of Leishmania mexicana in Neotoma micropus from 16 southern Texas localities was determined by screening 192 N. micropus using in vitro culture. Eight woodrats also were screened using the polymerase chain reaction (PCR). Forty-six Sigmodon hispidus from four localities were also tested. Seasonal transmission was investigated through trap-recapture studies at three localities and analysis of infections in juveniles. Fourteen N. micropus from four localities were culture-positive for L. mexicana, indicating an annual non-zero prevalence at these localities of 5.6-27%. Four additional infections at two foci were detected only by the PCR. Transmission occurred in the fall in each case in which season of transmission could be determined. No S. hispidus were positive. These data support the hypothesis that N. micropus is a reservoir of L. mexicana in Texas.