A study to characterize the epidemiological situation of bovine brucellosis in the State of Bahia was carried out in 2004. The State was divided into four similar production regions, 300 herds were randomly sampled in each region, and 10 to 15 adult bovine females were sampled in each of these herds. A total of 10,816 serum samples from 1,413 herds were collected. The serum samples were screened for antibodies to Brucella spp. by the Rose-Bengal Test (RBT), and all RBT-positive sera were re-tested by the 2-mercaptoethanol test (2-ME) for confirmation. A herd was considered positive if at least one animal was positive on both RBT and 2-ME tests. The prevalence of infected herds and seropositive adult bovine females in Bahia State were: 4.2% [3.1-5.3%] and 0.66% [0.41-0.93%], respectively. In the production regions, prevalence of infected herds and animals were, respectively: region 1, 5.8% [3.6-8.7%] and 0.86% [0.41-1.3%]; region 2, 3.1% [1.5-5.6%] and 1.2% [0.25-2.1%]; region 3, 6.3% [4.0-9.3%] and 1.7% [0.66-2.7%]; and region 4, 0.60% [0.07-2.2%] and 0.07%[0.00-0.2%]. In each herd, an epidemiological questionnaire was applied. The risk factors (odds ratio, OR) associated with the presence of the infection were: purchase of breeding animals (OR = 2.27) and presence of flood areas (OR= 1.76). Vaccination of heifers from three to eight months of age was a protective factor (OR=0.53).
cattle; brucellosis; prevalence; risk factors; Bahia; Brazil
