Tegumentary leishmaniasis in an area with epidemic levels of transmission Salta, Argentina, 1998.

The incidence of tegumentary leishmaniasis increased in October 1997, in an area close to Oran city, province of Salta. The leishmaniasis' epidemiolog y and the entomology of this outbreak were studied during June 1998 at Para je Las Carmelitas and Rio Blanco, places with high reported incidence. The prevalence of infection (Montenegro Skin Test reactive) was 171/1000 inhabi tants in Paraje Las Carmelitas and 790/1000 in Rio Bianco, while the rates of leishmaniasis' incidence (active ulcers) were 72/1000 and 790/1000. The prevalence differences among sex and age groups were not significant. The c linical and epidemiologic patterns were consistent with those reported in t he area for Leishmania (Viannia) braziliensis. Lutzomyia intermedia was the prevalent species (96%) among 2577 Phlebotominae collected, Lu. shannoni, Lu. cotelezzii y Lu. migonei were also present. The results about distribut ion of prevalence by age, and spatial distribution of Phlebotominae support ed deforestation-residual primary forest transmission hypotheses. Therefore , in Saita the epidemic outbreaks generated by extensive deforestation coul d be sustained and amplified because the human settlements are located clos e to the remaining primary forest "spots". Furthermore, in this scenario th e risk of human-vector contact increases by the subsistence or recreational activities performed in secondary transitional forests, and the presence o f domestic animals around the houses. The results are discussed in the fram e of possible control strategies.