Prevalence of Antibodies to Coxiella burnetii Among Veterinarians and Slaughterhouse Workers in Nova Scotia.

The complement fixation and the microimmunofluorescence tests were used to determine the prevalence of antibodies to Coxiella burnetii, the etiological agent of Q fever, among veterinarians and slaughterhouse workers in Nova Scotia. Seventeen percent of the 65 veterinarians and 12.5% of the 96 slaughterhouse workers tested had complement fixing antibodies to phase II C. burnetii antigen. Forty-nine percent of the veterinarians and 35% of the slaughterhouse workers had an antibody titer of >/= 1:8 to phase II C. burnetii antigen using the microimmunofluorescence test while 30% of the veterinarians and 14.5% of the slaughterhouse workers had antibodies detected to phase I antigen. Male veterinarians had a significantly higher rate of antibodies to C. burnetii phase II antigen compared with female veterinarians (p < 0.0087). An univariate analysis revealed that positive antibody titers (microimmunofluorescence test) to phase II antigen among veterinarians were significantly associated with exposure to cow, sheep and goat placentas; to stillborn calves, newborn foals, lambs and kids. By multivariate analysis the risk was highest for male veterinarians exposed to sheep placentas.Slaughtering cattle was a significant risk factor for positive antibody titers among slaughterhouse workers.We conclude that the high rate of antibodies to C. burnetii among Nova Scotia veterinarians and slaughterhouse workers is a reflection of the prevalence of Q fever in Nova Scotia and indicates that domestic ungulates are probably important in the epidemiology of Q fever in this province.