Trypanosoma cruzi in the sylvatic environment: distinct transmission cycles involving two sympatric marsupials

Abstract

Thirty-five specimens of Philander frenata and 36 Didelphis marsupialis were captured in the same Atlantic forest area of Brazil between 1992 and 1994. Haemocultures showed that 50% of P. frenata and 60% of D. marsupialis were infected with Trypansoma cruzi. Biological, biochemical and molecular characterization of the isolates suggested 2 distinct transmission cycles of T. cruzi occurred between these 2 sympatric didelphids. The T. cruzi isolates could be distinguished according to their association with each marsupial species. Biochemical characterization (multilocus enzyme electrophoresis) revealed 15 zymodemes; more variability was observed among the P. frenata isolates than among the isolates from D. marsupialis. The course of natural and experimental infection in D. marsupialis and P. frenata was different and suggested that D. marsupialis was more resistant to infection than P. frenata. In the studied area, P. frenata seems to be a more important reservoir of T. cruzi than D. marsupialis, since 40% of the characterized isolates from P. frenata belonged to the T. cruzi II group, which is associated with human infections.

Infectivity for mice of Trypanosoma cruzi I and II strains isolated from different hosts

“…This result agrees with Pinho et al (2000), who observed that even parasite isolates obtained from closely related hosts may differ in their biological properties. These investigators showed that isolates obtained from the marsupial Philander frenata were more virulent for Swiss mice than isolates from Didelphis marsupialis, suggesting that the biological characteristics of the parasite may differ depending on the host from which it was isolated.…”

The opossum Didelphis virginiana as a synanthropic reservoir of Trypanosoma cruzi in Dzidzilché, Yucatán, México

“…The existence of infected triatomines inside houses (16%) and the similarity in molecular patterns found in Yucatán strains isolated from opossums and humans (Zavala-Castro et al 1992) suggest that D. virginiana is participating as an infection source for humans as reported for other Latin-American countries (Zeledón 1970, Pinho et al 2000. Through an ongoing study on human population in the Yucatán Península, we will be able to confirm this hypothesis by comparing molecular characteristics of T. cruzi isolated from opossums and humans.…”

Trypanosoma cruzi and Chagas' Disease in the United States

“…Interestingly, two terrestrial marsupial genera (Philander and Monodelphis) can harbor both TcI and several other genotypes, whereas only TcI has been reported from the arboreal genus Didelphis (163,225,240). The genus Philander also displays a more severe inflammatory response to T. cruzi (162,163).…”