Trypanosoma cruzi circulating among dogs and triatomines in the endemic countryside of the State of Rio Grande do Norte, Brazil

Abstract

Vector transmission of Trypanosoma cruzi occurs in several areas of Brazil, including the northeastern region, and domestic animals can serve as reservoirs of the parasite. The aim of this study was to monitor dogs as domestic reservoirs for infection by T. cruzi, and the main triatomine species involved in parasite transmission in rural areas of municipalities in the State of Rio Grande do Norte, in northeastern, Brazil. Blood samples from dogs (n = 40) and manual triatomine capture were performed in domiciliary and peridomiciliary environments in rural areas of the towns of Acari, Caraúbas and Marcelino Vieira, between 2013 and 2016. Subsequently, infection of dogs was determined by Polymerase Chain Reaction (PCR), Enzyme-Linked Immunosorbent Assay (ELISA) for the detection of IgM and IgG isotypes and Indirect Immunofluorescence (IIF) reactions for detection of IgG. Triatomine infection was determined by PCR. Forty (16/40) percent of the dogs were seropositive for T. cruzi; 20.0% (8/40) of such reactivity indicated the acute phase, and 20.0% (8/40), the chronic phase. PCR was positive in 42.5% (17/40) of the dogs' blood samples. Specimens of Triatoma brasiliensis, Triatoma pseudomaculata, Rhodnius nasutus and Panstrongylus lutzi were found to be infected; however only T. brasiliensis nymphs and adults were infected in both environments. Triatomines evaluation showed 82.5% (94/114) of PCR positivity. Taken together, our results confirm that dogs are domestic reservoirs of T. cruzi in northeastern Brazil and T. brasiliensis is the main triatomine species correlated with parasite transmission in domiciliary environments. There is a continuing need to control peridomiciliary populations of triatomines and to implement continuous surveillance strategies for reservoirs with the help from the community.

Keywords: American trypanosomiasis; Canis familiaris; Natural infection; Polymerase chain reaction; Reservoir; Triatoma brasiliensis.