Leishmanias and leishmaniasis of the new world, with particular reference to Brazil

• Autor(a) principal: Lainson, Ralph
• Data de Publicação: 1973
• Outros Autores: Shaw, Jeffrey Jon
• Tipo de documento: Artigo
• Idioma: esp
• Título da fonte: Repositório Digital do Instituto Evandro Chagas (Patuá)
• Texto Completo: http://patua.iec.gov.br/handle/iec/2559
• topic: Reservat?rios de Doen?as; Leishmania / classifica??o; Am?rica do Norte; Am?rica do Sul; Brasil (BR)

One of the things that makes leishmaniasis of the Western Hemisphere a particularly enigmatic disease is lack of knowledge about its causative agents. All these agents are protozoans of the genus Leishmania, but while some may infect man little or not at all, others can cause serious disease. Past efforts to classify the parasites on the basis of clinical symptoms have produced a good deal of confusion. There were several reasons for this: first, man should properly be regarded as an accidental host of these leishmanias, which are maintained in nature by a wide spectrum of animal species; second, different patients may develop different reactions to the same parasite for immunological reasons; and third, leishmaniasis can last many years and its symptoms vary greatly during the course of the infection. Until fairly recently there was relatively little known about the hosts, vectors, and epidemiologies of the various leishmanias, and there had been little opportunity to set up an effective system of classification on this basis. However, during the 1960's a considerable amount of such work was accomplished and a number of new leishmanial parasites were discovered. This showed the importance of revising the existing taxonomy and provided a basis by which such revision could be achieved. The authors' revised classification of Western Hemisphere leishmanias is presented as part of this article. It is understood that few taxonomic systems are foolproof, and that all require repeated modification. The classification offered here is no exception to these rules. It is hoped, however, that it may help to orient our existing knowledge and help stimulate greater interest in the natural histories of these curious and important agents of human disease.