Prevalence of tuberculosis in cattle in the Dangme-West district of Ghana, public health implications

Bovine tuberculosis due to Mycobacterium bovis is a major cause of human gastrointestinal tuberculosis in developing countries where bovine milk is often not pasteurised before use. Little information is available on the prevalence of the disease in African cattle and its zoonotic impact. The Ghanaian Government, through its peri-urban dairy cattle development project, is promoting the use of milk and dairy products from local cows in selected districts of the country, including the Dangme-West district of the Greater Accra region. A survey was, therefore, undertaken to determine the prevalence of tuberculosis infection in cattle in this district and to assess the level of awareness with regard to the risks through milk consumption. The standard single intradermal comparative tuberculin test (SCITT) using purified protein derivative (PPD) of M. bovis and M. avium was used to detect cattle infected with M. bovis. The study established the prevalence of a 13.8% infection in cattle in the district although the prevalence was as high as 50% in some kraals. Prevalence was highest in the Ningo sub-district (19.0%), followed by Dodowa, the district capital (14.0%), while the other two sub-districts, Prampram and Osudoku had lower rates of 11.3 and 10.8%, respectively. Cattle of all ages and both sexes were affected, but the prevalence in cows was twice as high as that in heifers or bulls. The study also established that there is a considerable lack of knowledge about bovine tuberculosis among cattle owners and herdsmen in the community and that milk is often used untreated, thus increasing the risk of human infection. (C) 2000 Elsevier Science B.V. All rights reserved.