Seroprevalencia y factores de riesgo asociados a la brucelosis bovina en hatos lecheros de Tijuana, Baja California

Abstract

With the purpose of determining the prevalence of bovine brucellosis, as well as identifying some factors associated to this disease, a cross sectional study was carried out in dairy farms at Tijuana, Baja California, from September 1999 to September 2000. A total of 19,000 dairy cows aged 6 months or over, were studied. The tests used to detect this disease were the Card test and Fluorescence Polarization Assay (FPA). An epidemiological survey was applied in order to identify risk factors for brucellosis. Prevalence according to FPA was 6.4 %. When an univariate analysis was performed, the variables that showed a significant association with the disease were: not removing the remains of abortions and/or births (2.40 odds ratios (OR), presence of dogs in the facilities (OR= 2.65), milking positive reactors before or together with negative animals (OR= 6.74) and not getting rid of positive reactors (OR= 6.19). On the other hand, when a multivariate method was used (logistic regression), the only significant variables in the model were milking (adjusted OR= 4.65) and age, using a cutoff point of two years (OR adj. = 4.94). The global prevalence of brucellosis can be considered as moderate. The areas which showed higher prevalence were Gloria and Murua. Evidently, identification of risk factors associated to the presence of this disease, could be a very useful tool in a brucellosis control and eradication program.