Eco-epidemiological Survey of Trypanosoma cruzi in Dogs from Mendoza, Argentina

Urban domestic dog populations can provide important clues about the eco-epidemiological characteristics of Trypanosoma cruzi, the causative agent of Chagas disease (ChD). Given the limited data on ChD from the Metropolitan Area of Mendoza, Argentina, a seroprevalence survey of 327 dogs across an urban-rural gradient was conducted between April 2018 and May 2019. Seropositive cases were analyzed considering host, social, and environmental factors, subtypes (DTUs), and bloodstream parasite load. Seroprevalence of infection by T. cruzi total antigens (ELISA-H) was similar in urban (18%), interface (14%), and rural (21%) areas. Serotyping (recombinant TSSA-II antigen ELISA) revealed that 61% (37/61) of seropositive dogs carried the subtypes TcII, V and/or VI. There was no difference in the proportion of seropositive dogs versus seronegative dogs that lived with a person with ChD (9/62 = 14% vs. 35/265 = 13%, respectively). Parasite loads in seropositive dogs varied between < 0.10 and 1.18 parasite-equivalents/ml. Dogs with T. cruzi infection were in good health and nutritional condition, suggesting that they may have indeterminate or chronic stage infections. High infection rates in all areas and limited knowledge of owners about ChD and its triatomine vectors emphasize the need to intensify entomological studies, especially in urban areas, and promote vector information campaigns. This work shows that screening of dogs is a beneficial epidemiological tool to deepen studies on ChD from a One Health perspective.