Occurrence of antibody to Trypanosoma cruzi in dogs in the southeastern United States.

Seven of 365 dogs from Georgia and other southeastern states were seropositive for antibody to Trypanosoma cruzi by the complement-fixation (CF) test. Sera from 24 dogs, including the 7 dogs seropositive by CF test, were reactive at dilutions of 1:128 or 1:256 by the direct-agglutination (DA) test. Dogs with positive CF titers were significantly (P less than 0.05) younger than were the dogs in the total population surveyed. The occurrence of antibody to T cruzi was similar, regardless of the dogs' origin, sex, or length of hair. Dogs with specific antibody to T cruzi did not have clinical signs of disease related to the cardiovascular or gastrointestinal systems, the systems most frequently affected in American trypanosomiasis (Chagas' disease). Sera from an additional 20 dogs from Minnesota were examined by the DA test. One of these sera had a reaction at a dilution of 1:2, and 19 sera had no reaction in the DA test for antibody to T cruzi.