Brucellosis in a high risk occupational group: seroprevalence and analysis of risk factors

To estimate Brucella seropositivity among slaughterhouse workers of Lahore district and to elucidate risk factors associated with seropositivity to Brucella. During the year 2008, a cross-sectional study was conducted in four slaughterhouses of Lahore district. A sample of 360 workers was selected from these slaughterhouses through stratified random sampling on proportional basis. Workers were interviewed using a structured questionnaire to obtain risk factor information and their blood samples were collected to be screened for the presence of anti-Brucella IgG using Enzyme Linked Immunosorbent Assay (ELISA) technique. Data management and analysis were performed using SPSS (statistical package for social sciences) version 16. Risk factors associated with seropositivity to anti-Brucella IgG were identified by constructing a logistic regression model. Of the 360 serum samples tested, 21.7% (95% CI 17.44% - 25.96%) were positive by ELISA test. The logistic regression model identified age (OR 0.96, 95% CI 0.94-0.99), assistance in parturition of animal (OR 0.47, 95% CI 0.23-0.96), consuming raw milk (OR 2.25, 95% CI 1.04-4.87) and handling sheep (OR 0.30, 95% CI 0.09- 0.92) as risk factors for Brucella seropositivity among slaughterhouse workers of Lahore district. To reduce the burden of brucellosis, a national brucellosis control programme should be initiated with special emphasis on the high risk population of slaughterhouse workers.