EPIDEMIOLOGY OF CUTANEOUS LEISHMANIASIS IN COLOMBIA - A LONGITUDINAL-STUDY OF THE NATURAL-HISTORY, PREVALENCE, AND INCIDENCE OF INFECTION AND CLINICAL MANIFESTATIONS

This prospective study measured the incidence of Leishmania infection, by Leishmanin skin test (LST) conversion, and leishmaniasis, by new a cquisition of lesions, in a Leishmania braziliensis endemic area of Co lombia, during 7243 person-years. The incidence rate of infection and leishmaniasis varied greatly by village, ranging from 2.8 to 23.0/100 person-years and 0.0 to 20.4/1000 person-years, respectively. Adult ma les experienced greater rates of both infection and leishmaniasis. Mos t primary infections (91%) were subclinical initially. Typical scars w ere predictive of subsequent leishmaniases both for persons initially LST-reactive (risk ratio = 11.3, P = .003) and for those initially non reactive (risk ratio = 3.2, P = .02). Only one-third of the diagnosed leishmaniasis cases (24/77) were due to newly acquired infections in n aive hosts. The relative contribution of existing lesions, recurrences , and new infections to the burden of disease should be considered in the planning of leishmaniasis control programs.