Canine seroepidemiology of Trypanosoma cruzi in socially vulnerable urban communities of Salvador, Brazil

Chagas disease (CD), caused by Trypanosoma cruzi, remains a major neglected zoonosis in Latin America and represents persistent challenges in socially vulnerable urban settings. Domestic dogs are recognized as sensitive sentinels of environmental exposure to T. cruzi, yet data from urban communities remain limited. In this cross-sectional study, we investigated the seroprevalence of T. cruzi infection among dogs living in socially vulnerable urban communities on the periphery of Salvador, northeastern Brazil. Serum samples from 290 dogs were analyzed using indirect ELISA assays based on four chimeric recombinant IBMP antigens, and infection status was defined using latent class analysis. Seropositivity was identified in 9 dogs (5.1%) from the contiguous neighborhoods of Marechal Rondon and Alto do Cabrito, whereas all 113 dogs sampled in Pau da Lima were classified as seronegative, revealing marked intra-urban heterogeneity in canine exposure. Seropositive dogs were exclusively older animals (5–15 years), consistent with cumulative exposure, and none showed clinical signs compatible with CD at the time of sampling. These findings provide evidence of silent T. cruzi circulation in socially vulnerable urban communities and support the use of canine seroepidemiology as a complementary surveillance approach for identifying areas at risk of CD transmission in urban environments.