Prevalence of Coxiella burnetii in cattle at South Korean national breeding stock farms.

This is the first study to evaluate the serologic and molecular prevalence of Coxiella burnetii in cattle at national breeding stock farms in South Korea. These government farms have well-organized biosecurity and management systems to prevent livestock diseases. Of the 736 cattle in this study, 77 tested positive for antibodies against C. burnetii antigens (10.5%, 95% CI: 8.3-12.7) and 11 were positive for a C. burnetti infection on PCR analysis (1.5%, 95% CI: 0.6-2.4). Since the 16S rRNA sequences of C. burnetii from all 11 PCR-positive samples were identical, three representative samples (C-CN-3 from the southern region, C-JJ-9 from Jeju Island, and C-CB-37 from the central region) are described in this paper. These three sequences had 99.3-100% identity to those of C. burnetii deposited in GenBank. These sequences clustered with those from USA, Japan, and Greenland, underscoring the sequence similarity among C. burnetii isolates in these countries. Because C. burnetii was detected in cattle at well-managed national breeding stock farms, cattle at non-government operated farms may be more likely to be exposed to C. burnetii in South Korea. Thus, continuous surveillance and control strategies in animals and humans are required to prevent the transmission of C. burnetii to humans.