Rocky Mountain spotted fever in an urban canine population.

SUMMARY A survey for the prevalence of Rocky Mountain spotted fever antibodies in dogs from a well-defined endemic area in Columbus, Ohio (Franklin County), was conducted during the summer of 1981. Seventy- three blood samples from dogs in this area were testedby microimmunofiuorescence for antibodies to Rickettsia rickettsii and other rickettsial antigens. Thirty-three (45.2%) of these samples were positive for R rickettsii, with titers ranging from 1:8 to 1:2,048. Forcomparison, 137 blood samplesfrom dogs at the Franklin County Dog Pound also were tested. One dog (0,7%) from the comparison group was seropositive to R rickettsii, with a 1:64 liter. The results indicated a nidus of this disease within the city ofColumbus, Ohio.