TRYPANOSOMA-CRUZI - POLYMERASE CHAIN REACTION-BASED DETECTION IN DRIED FECES OF TRIATOMA-INFESTANS

PCR was employed to detect Trypanosoma cruzi DNA in Triatoma infestans dry fecal spots collected on filter papers. Both insects fed on exper imentally infected monkeys and insects collected in a Paraguayan endem ic area for Chagas' disease were examined. When the insects fed on a c hronically infected monkey with low parasitemia as revealed by direct microscopic observation (DMO), T. cruzi was detected in the insect fec es by PCR as soon as 2 days postfeeding. When the same experiment was performed on monkeys with parasitemia levels below the limit of detect ion by DMO, the degree of positivity found through PCR-Southern hybrid ization, applied on Day 8 postfeeding, was superior to that obtained t hrough xenoculture. These results suggest that PCR can be used to spee d the xenodiagnosis results with great sensitivity. On the other hand, when applied to the feces of triatomines collected in the field, 84% were positive by PCR-Southern hybridization, whereas only 26% were pos itive by DMO. Therefore, PCR could also be applied to the monitoring o f the infection status of triatomines which infest rural dwellings by examining only the feces left on paper sensors hung on the walls of th e houses. (C) 1996 Academic Press, Inc.