Prevalence and risk factors for brucellosis in goats in areas of Mexico with and without brucellosis control campaign

Brucellosis is a major constraint for small-scale goat farming systems in Mexico. This study estimated the prevalence of testing positive to brucellosis and identified and quantified risk factors in goats from small-scale farms of Michoacán that had participated in a brucellosis campaign (i.e. vaccination, serological testing, culling and awareness) and of Jalisco that had negligible brucellosis campaign participation. A cross-sectional serological survey was conducted among 1,713 goats of 83 flocks. The prevalence of testing positive to brucellosis was higher (38 %) in Jalisco than in Michoacán (11 %). Logistic regression analysis indicated that goats from Michoacán had lower odds to test positive for brucellosis (odds ratio (OR)=0.32, 95 % confidence interval (CI) 0.21–0.48) compared to goats from Jalisco. Goats in zero-grazing systems had lower odds than goats in grazing systems (OR=0.22, 95 % CI 0.09–0.57). When goats were kept in pens with low density (0.002 to 0.22 goat/m2), odds was lower (OR=0.44, 95 % CI 0.28–0.67) compared to goats kept in pens with higher density (0.23 to 1 goat/m2). Odds was higher for testing positive when farmers bought goats from goat traders (OR=1.82,95 % CI 1.15–2.87) compared to farmers who did not. If scavenger poultry had access to goat pens, the odds was half (OR=0.52, 95 % CI 0.33–0.83) of those where poultry had no access. Regular disinfection of the pen reduced the odds (OR=0.66, 95 % CI 0.44–0.99) compared to where disinfection was not regular. The brucellosis control campaign was effective in reducing brucellosis seropositivity.