A prevalence study of bovine tuberculosis by using abattoir meat inspection and tuberculin skin testing data, histopathological and IS 6110 PCR examination of tissues with tuberculous lesions in cattle in Ethiopia

The first aim of our study was to determine the trend of occurrence of tuberculous lesions in two abattoirs in Addis Ababa and Debre-Zeit (Ethiopia). The second aim of the study was to evaluate tuberculin skin test results in 10 farm areas with 85 dairy farms having 2,098 cattle in Addis Ababa. The third aim was to detect tuberculous lesions and causal agents from tissue samples of the respiratory tract and mesenteric lymph nodes of the slaughtered cattle. The ten year (1996-2005) retrospective analysis of the meat inspection of 2,455,289 slaughtered animals (cattle, sheep, goats, pigs) showed that 0.028% were found with tuberculous lesions in parenchymatous organs. Positive reactions to bovine tuberculin skin tests were obtained in 48% herds from 9 farm areas which included 392 animals. Tuberculous lesions were found in 34 animals by the meat inspection surveillance of 984 cattle. Histopathologically, granulomatous inflammation was evident in 3 animals with tuberculous lesions. A highly sensitive PCR (IS6110) was positive in 4 out of 34 animals with tuberculous lesions and in 1 animal without lesions. The analyzed data show that tuberculosis in cattle is still a problem in Ethiopia.