Leishmaniasis in Brazil: XVI. Isolation and identification of Leishmania species from sandflies, wild mammals and man in north Para State, with particular reference to L. braziliensis guyanensis causative agent of "pian-bois".

A total of 125 wild mammals (14 different species) were examined for evidence of infection with Leishmania in an area of primary forest highly endemic for "pian-bois", due to Leishmania braziliensis guyanensis, in north Pará State, Brazil. Parasites isolated were characterized biologically, and biochemically on enzymic profiles. L. b. guyanensis was isolated from the viscera of one lesser anteater (Tamandua tetradactyla) and one opossum (Didelphis marsupialis), and the skin of one rodent (Proechimys guyannensis). The isolates were indistinguishable from 10 others previously made from the sandfly vectors Lutzomyia umbratilis (five) and Lu. whitmani (five), and nine isolates from field-workers who became infected during these studies. Leishmania mexicana amazonensis was obtained from the skin of 21 animals, including three species of opossums (D. marsupialis, Philander opossum and Metachirus nudicaudatus) and two species of rodents (proechimys guyannensis and Dasyprocta sp.). A peripylarian Leishmania isolated from the viscera of two armadillos (Dasypus novemcinctus) was shown to be different, biologically and biochemically, from L. b. guyanensis and L. m. amazonensis. Four other isolates of Leishmania, from the rodents Rhipidomys leucodactylus (one) and P. guyannensis (three) have yet to be characterized owing to their very poor growth in both hamster skin and in vitro culture: they appear closest, however, to L. braziliensis braziliensis. The complexity of Amazonian leishmaniasis is discussed, and attention drawn to the importance of edentates as reservoir hosts of some leishmanias in the New World. Whereas L. mexicana subspecies appear largely restricted to the skin of their natural hosts, subspecies of L. braziliensis are commonly found in the viscera.