Slaughter surveillance for tuberculosis among cattle in three metropolitan abattoirs in Ghana

Despite its existence in Ghana, there is very little information on the extent or nature of bovine tuberculosis. This state of affairs may pose a serious public health threat through risks associated with the consumption of beef from infected cattle, dairy milk and other bovine products. A study to screen bovine carcasses with lesions suggestive of mycobacterial infection at necropsy in three selected abattoirs in Accra was conducted. A total of 2,886 cattle slaughtered in 3 abattoirs in the Greater Accra Region of Ghana between June and October, 2009 were examined at necropsy for lesions suggestive of bovine tuberculosis. Specimens taken from suspicious lesions were first subjected to Ziehl-Neelsen microscopy and then cultured on Löwenstein-Jensen media containing both pyruvate and glycerol. One hundred and fifty five (155) tissue samples were elicited from only lesions presenting with classical patho-morphological features consistent with bovine tuberculosis in organs found in 145 cattle. These results indicate that 5% (or 145/2886) of the cattle carcasses inspected at slaughter in the Accra region exhibited lesions suggestive of bovine tuberculosis and this poses a serious public health threat. Visual inspection at necropsy, provided done proficiently, could serve as the primary screening measure for beef contaminated with mycobacterial species in abattoirs in resource-poor settings. Microscopic examination, because of its revealed high specificity in this work may be employed, only as a supplementary test, in difficult cases.