Prevalence of American trypanosomiasis (Chagas disease) among dogs in Oklahoma

Objective-To determine the prevalence of Trypanosoma cruzi infection among dogs in Oklahoma. Design-Cross-sectional study. Animals-301 owned or impounded dogs related by ownership or general geograp hic location to 3 dogs determined to have trypanosomiasis. Procedures-Blood samples were obtained from dogs between November 1996 and September 1997. Infection status was determined by use of a radioimmunoprec ipitation assay. Second blood samples were obtained from some of the seropo sitive dogs for study by hemoculture and polymerase chain reaction (PCR) as say. Sites where infected dogs were found were inspected for triatomine ins ects, and light traps were used for vector trapping. Results-11 (3.6%) dogs were seropositive for T cruzi infection. Ten of the 11 were owned rural hunting dogs. Protozoal organisms isolated from the blo od of 1 seropositive dog were identified as T cruzi by PCR testing. Only 1 adult Triatoma sanguisuga was captured in a light trap at a site near infec ted dogs; this insect was not infected. Conclusions and Clinical Relevance-Our findings suggest that 7 cruzi is enz ootic in eastern Oklahoma. Measures that would reduce the risk of dogs acqu iring 7 cruzi infection are unlikely to be acceptable to their owners, and no effective drugs are available for treatment. The presence of 7 cruzi-inf ected dogs poses a threat of transmission to persons at risk of exposure to contaminated blood Veterinarians who practice in the southern United State s should be cognizant of this blood borne zoonosis and educate all personne l about appropriate precautions.