Flagellate infections of Brazilian sand flies (Diptera: Psychodidae): isolation in vitro and biochemical identification of Endotrypanum and Leishmania.

Flagellate infections were found in 1,063 of 18,895 sand flies collected in the states of Amazonas, Pará, Rondonia and Acre, Brazil. Infection rates were 13.4% (species group Shannoni); 7.5% (subgenus Nyssomyia); 6.7% (subgenus Lutzomyia series Cruciata); 0.5% (genus Psychodopygus) and 3.1% for other sand flies (various subgenera). Leishmania braziliensis guyanensis and L. mexicana amazonensis were isolated, respectively, from the known vectors, Lutzomyia umbratilis and L. flaviscutellata. Single stocks of L. braziliensis-like and L. mexicana-like organisms were isolated, respectively, from L. whitmani and L. yuilli. Thirty-eight flagellate stocks, isolated by direct culture from sand flies were characterized in detail by morphology in culture, behavior in hamsters and mice and by enzyme profiles. Sixteen stocks from Lutzomyia sp. (Shannoni group) were identified as Endotrypanum schaudinni; 8 stocks from Lutzomyia sp. (Shannoni group) were identified as Endotrypanum sp.; 7 stocks from Psychodopygus ayrozai and P. paraensis were identified as Leishmania sp. previously isolated from the armadillo, Dasypus novemcinctus; 2 stocks of Trypanosoma rangeli were isolated from recently fed Lutzomyia sp. (Shannoni group) sand flies; the remaining 5 stocks from L. umbratilis and L. yuilli could not be identified. Observations suggested that Shannoni group sand flies were the natural vectors of Endotrypanum. Leishmania sp. infections in the man-biting flies P. ayrozai and P. paraensis were restricted to the midgut and associated with recent bloodmeals. Unidentified flagellates in L. umbratilis and L. yuilli were distributed throughout the digestive tract with no trace of bloodmeals.

Chagas' disease in the Amazon basin IV. Host records of Trypanosoma cruzi zymodemes in the states of Amazonas and Rondonia, Brazil.

Of 151 Trypanosoma cruzi stocks from 117 different individual hosts collected in the states of Amazonas and Rondonia, 147 from 113 hosts were identified as zymodeme 1 (Z1). These included T. cruzi stocks from three marsupial species, two rodent species and three triatomine species although most were from the common opossum, Didelphis marsupialis. One T. cruzi stock from Rhodnius robustus was identified as Z1 with a Z3 PGM character, one from Sciurus sp. as Z3 and two from Monodelphis brevicaudata and Panstrongylus geniculatus as Z3 with a Z1 ASAT character. The ways in which stocks were isolated and grown up in vitro did not influence isozyme profile. These results support earlier evidence from Pará State that Z2 is absent from the Amazon basin and that the distribution of T. cruzi zymodemes in this region is quite different to that in endemic areas on the south of the continent.