Leishmaniasis in Texas: Epidemiology and clinical aspects of human cases

Twenty-seven autochthonous cases of cutaneous leishmaniasis in Texas were identified by contact with dermatologists and State Health Department officials, and by a review of medical records, pathology reports, and previously published case reports. Fifteen cases were previously unreported. Although the date of onset of the first recognized case was 1903, in 20 of the cases the date of onset of the lesion(s) was in 1980-1989. Twelve cases were female; 15 were male. Age at diagnosis ranged from two to 86 (median 37) years. The disease was identified significantly more frequently in younger males and older females. The distribution of cases closely followed the distribution of Neotoma micropus, a rodent host for Leishmania mexicana. The most common risk factor appeared to be residence or activity in close proximity to woodrat habitat. Two cases lived in central Texas; the remainder had a residence in, or history of travel to, southern Texas. A majority of cases were first recognized during the cooler months of the year. Most lesions began as papules or nodules that subsequently ulcerated. In 20 cases, a single lesion was present. Five cases had resolution of their lesions without receiving specific anti-leishmanial therapy; lesions of 17 resolved after treatment with a variety of therapies. One life-long case of disseminated disease failed to respond to treatment, and four cases were lost to follow-up. A Leishmania-specific lymphocyte proliferation assay gave a positive response for four of five cases tested. Screening of 13 family members found no evidence of subclinical infection. These 27 cases, and two recently recognized cases reported in a note added in proof, indicate that cutaneous leishmaniasis may be more common in Texas than previously thought.