SHORT REPORT: A FOCUS OF LEISHMANIA MEXICANA NEAR TUCSON, ARIZONA

Abstract. Twenty-eight white-throated woodrats (Neotoma albigula) collected in Pima County, Arizona were screened for Leishmania using culture and the polymerase chain reaction (PCR). Two rodents were culture positive. Isoenzyme analysis determined the isolates to be Leishmania mexicana. The two culture-positive and four additional rodents were determined to be Leishmania-positive by the PCR. These isolates extend the geographic and ecologic range of enzootic leishmaniasis in the United States and represent a new host record. The leishmaniases are vector-borne, parasitic diseases caused by protozoans in the genus Leishmania. Leishmania mexicana, which causes cutaneous leishmaniasis, infects hu-mans and a variety of vertebrate hosts in North, Central and South America and occurs in a wide variety of ecologic set-tings.1 Twenty-nine autochthonous cases of human cutane-ous leishmaniasis are known from the United States, all in southern or central Texas.2 Enzootic foci have been identified only in the semi-arid brush country of southern Texas, in a southern plains woodrat (Neotoma micropus)–sand fly (Lut-zomyia anthophora) cycle.3–5 We hypothesized that enzootic foci of L. mexicana could exist in the United States wherever sand flies occur in close association with rodents or other potential hosts of Leish-mania.2 Mead and Cupp6 found Lu. anthophora associated with white-throated woodrats (Neotoma albigula) and rock squirrels (Spermophilus variegatus) at the Buenos Aires Na-tional Wildlife Refuge (BANWR) in Pima County, Arizona, motivating us to collect and screen rodents from that area for L. mexicana. We report the results of those screenings. Live trapping with Sherman traps (13 3 13 3 37.5 cm