We assessed the distribution of
Trypanosoma cruzi
infection in peridomestic triatomines collected manually at a district-wide scale in rural villages around Olta, Western Argentina, and typed the isolated strains according to their pathogenicity to laboratory mice. Of 1623 triatomines examined, only 14 (0.9%) were infected with
T. cruzi based on microscopical examination of feces. The prevalence of
T. cruzi infection was 0.8% in
Triatoma infestans, 2.3% in
T. guasayana, and nil in
T. garciabesi,
T. platensis, and
T. eratyrusiformis. Local transmission occurred in kitchens, store-rooms and goat corrals or nearby, though at very low levels.
T. cruzi was detected by at least one parasitological method in 11 (79%) of 14 microscope-positive bugs. Hemoculture was the most sensitive method (67%) followed by culture of organ homogenates, histopathology or xenodiagnosis of inoculated suckling mice (55-58%), and culture of microscope-positive bug feces (46%). The evidence suggests that most of the isolated
T. cruzi strains would be myotropic type III. Our study establishes for the first time that peridomestic, microscope-positive
T. guasayana nymphs were actually infected with
T. cruzi, and may be implicated as a putative secondary vector of
T. cruzi in domestic or peridomestic sites.
