Risk factors associated with prevalence of tuberculosis-like lesions and associated mycobacteria in cattle slaughtered at public and export abattoirs in Ethiopia.

ABSTRACT

This study was aimed at investigating risk factors associated with prevalence of tuberculosis (TB)-like lesions and associated mycobacteria in Ethiopian cattle slaughtered. The study was carried out during 2006-2007 in five selected municipal and export abattoirs. Methods of investigation involved detailed necropsy examination of carcasses and isolation of mycobacteria from pathologic tissue specimens. Factors of animal and environment origin were recorded and examined as explanatory variables in relation to the presence or absence of TB-like lesions and the presence of viable mycobacteria. Multivariable logistic regression analysis was used to identify risk factors associated with prevalence of TB-like lesions and mycobacteria. Out of 3,322 carcasses inspected, 10.2% (95% confidence interval (CI) [9.2-11.3]) and 3.2% (95% CI [2.6-3.8]) were positive, respectively, based on necropsy and bacteriologic examinations. The highest and lowest lesion prevalence was recorded in Adama (24.7%) and Yabello (4.2%), respectively. Multivariable logistic regression analysis identified age, breed, abattoir location, geographic origin and management system as being risk factors for prevalence of TB-like lesions and occurrence of viable mycobacteria in Ethiopian cattle. The study demonstrated mycobacterial infection as important infectious disease of Ethiopian cattle. The reported confirmed cases of the disease in different management and geographic settings in Ethiopia disproved the earlier held opinion of its occurrence as a low sporadic profile. In view of a dietary proclivity of Ethiopian communities (milk and meat are predominantly consumed raw) and lifestyle (close contact of people with animals), the risk of bovine tuberculosis as a public health threat is eminent.