Industrial Dairy Cattle Farms in Hungary Source of Coxiella burnetii Infection in Humans.

Previous research has demonstrated a high prevalence of Coxiella burnetii in the bulk tank milk on large industrial dairy farms of the central and eastern European region. The aim of this survey was to estimate the prevalence of specific IgG antibodies to C. burnetii proving previous infection among dairy farm workers and to determine the possible risk factors. Serum samples from veterinarians, inseminators, animal caretakers, milking parlor workers, and herd managers working on dairy farms were tested for the presence of IgG to phase I and phase II of C. burnetii using an indirect microimmunofluorescence assay. Antibodies phase II to C. burnetii were detected in 59 out of 70 individuals tested (84.3%). All occupational groups are highly exposed to C. burnetii infection. Veterinarians, inseminators, and animal caretakers had 100% seropositivity rate of phase II, whereas the seropositivity rate found among herd managers and milking parlor workers was 71.4% and 47%, respectively. The findings of this survey suggest that the risk of C. burnetii infection is correlated with cattle density in the large dairy farms and also with occupational groups.