Prevalence of antibodies to Coxiella burnetii in Japan.

We evaluated the prevalence of Coxiella burnetii antibodies in 626 human serum samples (275 from veterinarians, 107 from meat-processing workers, 184 from respiratory-disorder patients, and 60 from healthy humans) by the indirect immunofluorescence test. Of the serum samples examined, 54 (8.6%) and 103 (16.5%) reacted positively to phase I and II antigens, respectively, of C. burnetii. The rates differed for healthy humans and respiratory-disorder patients. Antibody prevalence was high for healthy humans living in close contact with animals (e.g., veterinarians and meat-processing workers).