Investigation regarding the presence of Trypanosoma cruzi in triatomines and humans in rural households in the State of Paraná, southern Brazil

Trypanosoma cruzi, the etiologic agent of Chagas disease (CD), is transmitted by hematophagous insects belonging to the subfamily Triatominae. After elimination of Triatoma infestans, the infestation of human dwellings by secondary species of vectors continues to pose a risk of transmission of the parasite. Our aim was to investigate the T. cruzi presence in triatomines and humans in rural households in the State of Paraná, southern Brazil. The capture of the insects was carried out by technicians of the municipalities after residents reported the outbreak. Five residents and 27 triatomines captured in four municipalities in the North and Midwest of the state were evaluated. The research of T. cruzi was carried out using parasitological, serological, and molecular techniques, in human blood, excreta, intestinal contents and insect macerate. Panstrongylus megistus, P. geniculatus and Triatoma sp. were identified. Ten specimens of P. megistus were captured in a house in Mandaguari with five residents and presented an infection rate of 70% for T. cruzi like. All residents tested negative for T. cruzi infection. Another 15 P. megistus were captured in the peridomicile in Janiópolis and had 100.0% positivity. The only adult specimen of P. geniculatus captured in the intradomicile in Amaporã, as well as the nymph of Triatoma in the peridomicile in Paiçandu, were negative. The finding of P. megistus naturally infected by T. cruzi in households in rural area of Paraná demonstrates a potential risk of vector transmission of CD in these regions.