Bovine Tuberculosis in Western Tigray, northern Ethiopia

Bovine tuberculosis (BTB) is a chronic infectious disease of animals and humans characterized by the formation of granulomas in tissues and organs, principally caused by Mycobacterium Bovis (M. bovis). A cross-sectional study was conducted from September 2010 to May 2011 with the objectives to determine the prevalence of BTB, to characterize the isolates of Mycobacterium tuberculosis complex, and to assess zoonotic importance of BTB based on questionnaire survey in Setit and Kafta Humera districts, Western Zone of Tigray Region. Thirty one herds comprising 484 cattle were subjected to CIDT test. Accordingly, the individual animal prevalences were 6.6% (95% CI, 4.4-8.8) and 8.7% (95% CI, 6.2-11.2) at cut-offs greater than 4 mm and 2 mm, respectively while the herd prevalences were 61.3 % (95% CI, 43.1-79.5) at cut-off >4 mm and 77.4% (95% CI, 61.8-93.0) at cut-off >2 mm. On abattoir survey, a total of 582 cattle were subjected to postmortem examination, of which 5.8% were found to be positive for gross tuberculous lesions. Of 34 tissue specimens collected from the gross lesions 35.3% (12/34) were positive on primary culture, of which four showed a positive signal for the genus Mycob