VISCERAL LEISHMANIASIS IN TERESINA, STATE OF PIAUI, BRAZIL - PRELIMINARY-OBSERVATIONS ON THE DETECTION AND TRANSMISSIBILITY OF CANINE AND SANDFLY INFECTIONS

A Leishmania donovani-complex specific DNA probe was used to confirm t he widespread dissemination of amastigotes in apparently normal skin o f dogs with canine visceral leishmaniasis. When Lutzomyia longipalpis were fed on abnormal skin of five naturally infected dogs 57 of 163 (3 5%) flies became infected: four of 65 flies (6%) became infected when fed on apparently normal skin. The bite of a single sandfly that had f ed seven days previously on a naturally infected dog transmitted tile infection to a young dog from a non-endemic area. Within 22 days a les ion had developed at tile site of the infective bite (inner ear): 98 d ays after infection organisms had not disseminated throughout tile ski n, bone marrow, spleen or liver and the animal was still serologically negative by indirect immunofluorescence and dot-enzyme-linked immunos orbent assay. When fed Lu. longipalpis were captured from a kennel wit h a sick dog known to be infected, 33 out of 49 (67%) of flies contain ed promastigotes. In contrast only two infections were detected among more than 200 sandflies captured in houses. These observations confirm the ease of transmissibility of L. chagasi from dog to sandfly to dog in Teresina. It is likely that canine VL is the major source of human VL by the transmission route dog-sandfly-human. The Lmet2 DNA probe w as a useful epidemiological tool for detecting L. chagasi in sandflies .