Environmental exposure to Coxiella burnetii: a sero-epidemiologic survey among domestic animals.

The prevalence of agglutinating serum antibodies against Coxiella burnetii, the cause of Q fever in humans, was tested in a hospital population of companion animals and livestock in California during 1973--1975. A sample of stray dogs was also tested. Among the hospitalized animals 346 (48%) of 724 dogs, 7 (9%) of 80 cats, 9 (32%) of 28 cattle and 31 (26%) of 121 horses had antibodies against C. burnetii. Of 316 stray dogs 208 (66%) were seropositive. The overall prevalence of 53% among 1040 dogs tested was comparable to the 63% antibody prevalence found in an earlier survey among coyotes and foxes in wildlife areas of California. When the dog was considered as a sentinel animal for the presence of C. burnetii surrounding household environments, it was hypothesized that the common, low level exposures in the community are similar to those found in more remote wildlife areas.