Evolution of bovine brucellosis in Colombia over a 7-year period (2006-2012)

Bovine brucellosis is endemic in Colombia, and is a mandatory notifiable disease, subjected to a control program based on four surveillance procedures: passive surveillance, test-and-remove, certification of disease-free farms, and animal movements. The objective of this study is to estimate the evolution of bovine brucellosis in Colombia over a 7-year period (2006-2012) using data from the official control program. A total of 58 epidemiologic variables were analyzed for each year at the department level. Univariate descriptive analysis and principal components analysis (PCA) were performed to ascertain the behavior of the variables. These programs covered 3% of the census in 2006, increasing to 15% in 2012. The percentage of positive farms averaged 22% in 2006 and 23% in 2012. The highest proportion of positive farms was in the Orinoquia region (24.6 to 49.6%); the lowest was in the Amazon region, (17.9 to 32.7%). The percentage of positive animals presented certain differences between years but without any clear trend (4.7% in 2006 and 4.6% in 2012), indicating that the brucellosis control program had a low impact in Colombia in these years. The results for each surveillance procedure were 6.8% for passive surveillance, 5.9% for test-and-remove, and 4.4% both in disease-free farms and in animal movement tests. The results obtained by PCA led to finding three different clusters: geographic areas with low bovine production and low bovine brucellosis surveillance, areas with medium bovine production and medium surveillance for bovine brucellosis, and areas with a predominant bovine production, applying sanitary measures to control bovine brucellosis.