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

Abstract

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/m(2)), 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/m(2)). 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.

‘It is better to herd than be herded’: making a living with goats in the Bajío region, Mexico

“…The goat milk market is in a vicious cycle where milk price is low and therefore the milk hygiene quality is low. Brucellosis, a zoonosis endemic in goat flocks of the region (Oseguera Montiel et al 2013), does not receive enough attention. This is not an issue in the eyes of the cajeta industry.…”

Financial analysis of brucellosis control for small-scale goat farming in the Bajío region, Mexico

“…The four scenarios were chosen because they represent the core of the brucellosis control and eradication campaign in Mexico (SAGARPA, 1996). The initial infected level was assumed to be 20%, the average seroprevalence in the area (Oseguera Montiel et al, 2013). The effective contact rate (ˇ) refers to the rate in which two goats come into effective contact per unit of time (Vynnycky and White, 2010).…”

“…The effective contact rate (ˇ) refers to the rate in which two goats come into effective contact per unit of time (Vynnycky and White, 2010). It was estimated with Berkeley Madonna (v. 8.0.1) software using the curve fit function and based on the assumption that an endemic equilibrium occurred at a prevalence of 38%, the seroprevalence of brucellosis in flocks of the region where brucellosis control is lacking (Oseguera Montiel et al, 2013). Due to the practice of extensive grazing on communal land, one large village flock was assumed resulting in a high effective contact rate.…”

“…Despite these severe consequences in both goats and humans, brucellosis in livestock is still uncontrolled in many countries of the global South (OIE, 2005). In the Bajío region of Mexico for example, where small-scale goat husbandry is common, the average seroprevalence of caprine brucellosis was estimated to be 20% (Oseguera Montiel et al, 2013).…”

“…Reality is different, however, because local governments' and farmers' efforts and participation in brucellosis control is variable between municipalities, states and villages, resulting in a heterogeneous brucellosis prevalence across the country and within regions, e.g. a prevalence of 38% was reported for the state of Jalisco while it was 11% in the neighbouring state of Michoacán (Oseguera Montiel et al, 2013).…”