Seroreactivity and Risk Factors Associated with Human Brucellosis among Cattle Slaughterhouse Workers in South Korea

The prevalence rate of human brucellosis in high-risk populations, as well as their risk factors, have not been well understood in South Korea. In this cross-sectional study, we investigated the seroreactivity and risk factors associated with human brucellosis among South Korean cattle slaughterhouse workers. We enrolled 922 subjects working in 71 slaughterhouses across the country in 2012. A structured questionnaire was used to obtain data from the subjects, following which blood samples were collected and tested using the microagglutination test; serum titers ≥ 1:20 were considered reactive. Independent risk factors were identified using multivariate logistic regression analysis with backward elimination. Overall, 62 of 922 participants (6.7%) exhibited seroreactivity for brucellosis, and 0.4% had a seroprevalence at a dilution of 1:160. Multivariate analysis revealed that the risk factors for human brucellosis seroreactivity included large-scale slaughtering (≥100 cattle per day; odds ratio (OR), 5.41; 95% confidence interval (CI), 2.95⁻9.91) and medium-scale slaughtering (50⁻99 cattle per day; OR, 2.53; 95% CI, 1.16⁻5.51). Moreover, the risk of brucellosis infection was significantly lower among slaughterhouse workers who always wear protective glasses (OR, 0.27; 95% CI, 0.11⁻0.69) than in those who sometimes or rarely wore such glasses. Regular and consistent use of personal protective equipment, especially protective glasses, should be encouraged among cattle slaughterhouse workers to reduce brucellosis infection.