Epidemiologic studies of chagas' disease in the urban zone of Teresina. State of Piauí, northeastern Brazil

The triatomine species Rhodnius nasutus and Triatoma pseudomaculata were captured on palm trees Orbignya martiana "babaçu ", in the urban zone of Teresina. This kind of palm tree is largely distributed in Piauí State. The predominant species was R. nasutus; the young in stars predominated. The infestation index of palm trees and the infection index of triatomines by flagellates were 96.0 ana 29.1%, respectively. Marsupiais, bats and a rodent were captured in palm trees. The flagellates found in both triatomines ana marsupiais were morphologically and biologically indistinguishable from Trypanosoma cruzi. Forty seven percent (481/1,025) of triatomines were found concentrated in six palm trees where marsupiais circulated. Of the total of 1,025 triatomines 230 (22%) were infected by flagellates and 53.0% (123/230) of these infected triatomines were present in the same six palm trees. No evidence of triatomine domiciliation or human transmission was observed in the houses in the vicinity of palm trees. The results suggest that marsupiais play an important role in the life-cycle of T. cruzi in this region. The natural focus of Chagas' disease, demonstrated in the present study could represent a potential epidemiological threat.

Trypanosoma cruzi-like bloodstream trypomastigotes in bats from the State of Piauí, Northeastern Brazil

One-hundred and thirty-five bats from 12 species were examined for thepresence of trypomastigotes by means of direct blood examination, xenodiagnosis, and hemoculture. Of those, 44 specimens (32.6%) from 8 species were infected with trypanosomes. Phyllostomus discolor discolor presented the highest rate of infection, being captured only in one locality, while Phyllostomus hastatus hastatus captured in four localities showed high rates. Two species, Anoura geoffroyii and Pteronotus (Phillodia) pamelli rubiginosa, were found infected by T. cruzi-like trypanosomes, apparently described for thefirst time. Flagellates from Artibeus jamaisensis jamaisensisa and A. geoffroyii were able toproduce detectable parasitaemia in young mice. One triatomine bug was found infected in natural conditions, Triatoma brasiliensis was associated with a P.h. hastatus colony, in which six captured bats were also found infected.