Abstract
Dogs play a crucial role in the transmission cycle of Trypanosoma cruzi and their presence in domicile increases the risk of infection in humans. In Yucatán, Mexico previous studies have reported T. cruzi infection in dogs from both rural and urban areas, which we expanded here, to better understand infection dynamics. A total of 186-dogs were screened for T. cruzi infection by PCR and serology. Parasite burden, genotype, immune response, cardiac alterations, and roaming behavior of the dogs were analyzed. The T. cruzi prevalence was 26.8% (50/186). Genotyping of T. cruzi revealed the predominance of TcI parasites, although most dogs (15/25, 60%) harbored mixed infections with additional DTUs including TcII, TcIV, TcV and TcVI. Antibodies against T. cruzi proteins were detected in > 90% of infected dogs, confirming their immunogenicity in natural infections. Mild ECG abnormalities were present in 40% of infected dogs. A logistic model suggested that the interplay between the host responses to multiple parasite strains could mediate differences in disease severity (P = 0.0002, R(2) = 0.65). Finally, parasite diversity and dog roaming behavior support a role of dogs as an important link in T. cruzi transmission cycles among habitats. Together, these data provide a strong rationale to target dogs in integrated Chagas disease control interventions.