Human brucellosis: seroprevalence and associated exposure factors among abattoir workers in Abuja, Nigeria - 2011

Introduction: Brucellosis, a neglected debilitating zoonosis, is a recognized occupational hazard with a high prevalence in developing countries. Transmission to humans can occur through contact with infected animals or animal products. Brucellosis presents with fever. In Nigeria, there is a possibility of missed diagnoses by physicians leading to a long debilitating illness. We conducted a study to determine the seroprevalence and factors associated with Human Brucellosis (HB) among abattoir-workers in Abuja, Nigeria. Methods: We conducted a cross-sectional study and selected abattoir-workers using stratified random sampling. Structured questionnaires were used to collect data on demographics and exposure-factors. We tested the workers' serum-samples using Rose-Bengal (RBPT) and ELISA tests. A worker with HB was one whose serum tested positive to RBPT or ELISA. We tested differences in proportions between workers with HB and those without HB using odds-ratio and X-2 tests. Results: Of 224 workers, 172 (76.8%) were male and mean age was 30 + 9.0 years. Of 224 sera collected, 54 were positive giving a seroprevalence of 24.1%. Of these, 32 (59.3%) were butchers, and 11 (20.4%) were meat-sellers. Slaughtering animals while having open-wounds (Odds-ratio (OR)=2.15, 95% Confidence Interval (CI)=1.15-4.04); occupational-exposure of >5years (OR=2.30, CI=1.11-4.78) and eating raw meat (OR=2.75, CI=1.21-6.26) were significantly associated with HB. Multivariate analyses showed that occupational-exposure of >5years ( Adjusted OR (AOR) = 2.45, CI=1.15 - 5.30) and eating raw-meat (AOR=2.64, CI=1.14 - 6.14) remained significantly associated with HB. Conclusion: Seroprevalence of HB among abattoir-workers in Abuja was high. Factors associated with HB were occupational-exposure of >5years and eating raw-meat. Abattoir-workers should be discouraged from eating raw-meat and educated on adherence to safe animal-product handling practices.