The dermal leishmaniases of Brazil, with special reference to the eco-epidemiology of the disease in Amazonia

Abstract

Six species of Leishmania are at present known to cause cutaneous and/or mucocutaneous leishmaniasis in Brazil, and they are all to be found in the Amazon region of this country. The eco-epidemiology of each is discussed, with the observation that the Amazonian leishmaniases are all zoonoses, with their source in silvatic mammals and phlebotomine sandfly vectors. With man's destruction of the natural forest in southern Brazil, some sandfly species have survived by adapting to a peridomestic or domiciliary habitat in rural areas. Some domestic animals, such as dogs and equines are seemingly now involved in the epidemiology of the disease. No such process has yet been reported in the Amazon region, but may well take place with the continuing devastation of its forest.

Fauna de flebotomíneos (Diptera: Psychodidae) em um foco de leishmaniose tegumentar americana na área periurbana de Manaus, Estado do Amazonas

“…Um segundo padrão, periflorestal, com um ciclo de transmissão no peridomicílio e nas áreas marginais em áreas de ocupação situadas dentro do raio de vôo dos vetores silvestres 2 10 . Entretanto, a maioria dos casos de infecção por Leishmania guyanensis é contraída dentro da floresta, durante o dia, quando espécimes de Nyssomyia umbratilis são perturbados nos seus refúgios nas bases dos troncos das árvores 3 6 , principalmente em atividades de desmatamento 24 .…”

Lutzomyia longipalpis and the eco-epidemiology of American visceral leishmaniasis, with particular reference to Brazil: a review

“…Lu. flaviscutellata is occasionally found invading the peridomestic habitat in areas where isolated cases of Amazonian AVL have been diagnosed (Lainson et al 1994). It is not greatly attracted to man, however, so its role as a secondary vector, if indeed it exists, would be of minor importance.…”

Phase 1 Study of an Inactivated Vaccine against American Tegumentary Leishmaniasis in Normal Volunteers in Brazil

“…In Brazil, there are at least six species of dermotropic Leishmania for humans in various ecological situations (Lainson et al 1994). Control is thus complex, and there are different patterns of transmission (Marzochi & Marzochi 1994).…”

“…In the Amazon region it implies human contact with forests through participation of sylvatic reservoirs and various sandfly vectors. In areas that have been settled longer, transmission is generally rural and peridomiciliary, and there is discussion concerning possible sources of infection such as canines, equids, rodents, and humans, as well as association with various species of sandflies which adapt well to altered environments (Desjeux 1992, Marzochi 1992, Lainson et al 1994, Marzochi & Marzochi 1994). Subclinical infection is highly frequent (Marzochi et al 1980, Isaza 1980, Guerra et al 1985, Cordova-Uscanga et al 1993) and probably underestimated.…”