Leishmania chagasi Cunha & Chagas, 1937: indigenous or introduced? A brief review

Abstract

This review focused on the etiology of American visceral leishmaniasis due to a recent polemic regarding the origin of its etiological agent, Leishmania chagasi Cunha & Chagas, 1937. This parasite was described as a new Leishmania species in light of its inability to produce experimentally visceral disease in domestic dogs; this characteristic distinguished it from the other prior known etiologic agent of visceral leishmaniasis in the Mediterranean Basin of Europe, Leishmania infantum Nicolle, 1908. After 50 years of Leishmania chagasi investigation, the genus Leishmania was reviewed and the parasite was reclassified as a member of the subgenus Leishmania, species Leishmania (Leishmania) chagasi. Recently, after molecular analysis using the random amplified polymorphic DNA (RAPD) technique that compared L. (L.) chagasi with L. (L.) infantum, it was concluded that these species were genetically indistinguishable and, therefore, L. (L.) chagasi was regarded as synonymous with L. (L.) infantum. For this reason, this review has evaluated all knowledge concerning the eco-epidemiology of L. (L.) chagasi in the Brazilian Amazon, principally in regard to the sylvatic habits of its phlebotomine sandfly vector, Lutzomyia longipalpis, and its vertebrate reservoir, the wild fox Cerdocyon thous, with the aim of showing that L. (L.) chagasi cannot be neglected from the parasitological investigation of visceral leishmaniasis in the New World; it must be considered, at least, at the subspecific level as Leishmania (L.) infantum chagasi.