Introduction Bovine tuberculosis (BTB) caused by Mycobacterium bovis is a major cause of human gastrointestinal tuberculosis in developing countries [6]. Un-pasteurised contaminated milk and other secretions or tissues from animal hosts can serve as the source of infection for humans [14], milk through ingestion being regarded as the principal one. Primary invasion, through pharynx or intestine, results in lymphadenitis of adjacent lymph nodes [24]. Haematogenous dissemination to vertebrae can cause bone disorders that can result in a hunchback. Infection through inhalation of aerosol causes in humans the development of a primary lesion (tubercle) in the respiratory tract [24]. M. bovis is a member of the Mycobacterium tuberculosis com- plex, a group of mycobacterial species that includes M. tuberculosis, M. bovis, M. africanum and M. microti. Human infection with any of these species of mycobacteria can result in tuberculosis and, regarding the responsible species, the disease is similar clinically, radiologically, or pathologi- cally [22]. Sub-populations at risk of M. bovis infection include any population consuming un-pasteurised contami- nated milk, abattoir workers, veterinarians, hunters, and HIV-infected or other potentially immunogenically-compro- mised populations [11, 14, 18]. M. bovis causes tuberculosis in a broad range of mamma- lian hosts including cattle and other ruminants [5]. Clinical tuberculosis in cattle is typically a debilitating illness charac- terised by progressive emaciation and development of tubercle in any tissue [26], especially in the lungs and lymph nodes of the thoracic cavity. Maintenance of M. bovis is pri- marily related to ruminants although other species have been demonstrated to maintain infection from generation to gene- ration [7]. Given that HIV and M. bovis transmission are high in Africa, with 90% of the population of Africa living in areas where neither pasteurisation nor BTB control programmes occur and up to one in ten adults are infected with HIV, the association between these two diseases is of particular concern on this continent [9, 18]. Ethiopia, with an estimated number of 2.9 million adults (15-49 years) living with HIV/AIDS in year 1999, is the second most infected country with HIV in Africa next to South Africa [27]. Though the Prevalence of bovine tuberculosis in zebu cattle under traditional animal husbandry in Boji district of western Ethiopia G. LAVAL 1 * and G. AMENI 2 1 International Livestock Research Institute, Livestock Policy Analysis Programme, P.O. Box, 5689, Addis Ababa, Ethiopia (Seconded from CIRAD-EMVT, TA/30A, 34398 Montpellier Cedex 5, France) 2 Institute of Pathobiology, Addis Ababa University home-based at the Faculty of Veterinary Medicine, Addis Ababa University, P O Box 1176, Addis Ababa, Ethiopia * Corresponding author : e-mail:geraudparis@hotmail.com Villa Sarepian - 64310 F. - SARE RÉSUMÉ Prévalence de la tuberculose bovine en élevage traditionnel de zébus dans le district de Boji (Ouest de l’Ethiopie). Par G. LAVAL et G. AMENI. Une étude a été réalisée dans le district de Boji (Ouest de l’Ethiopie) afin de déterminer la prévalence individuelle et la prévalence troupeau de la tuberculose bovine en élevage de zébus. Cette étude concernait 62 trou- peaux totalisant 780 têtes de bétail. Trente cinq des 62 troupeaux furent tes- tés par intra-dermo tuberculination simple et 27 autres par intra-dermo tuberculination comparative. Le test de tuberculination simple a permis d’estimer une prévalence troupeau de 51% (18/35) et une prévalence indi- viduelle de 4.1 % (19/460). Le test de tuberculination comparative a quant à lui permis d’estimer une prévalence troupeau de 19% (5/27) et une préva- lence individuelle de 1,6% (5/320) et de révéler 2,2% (7/320) de réactions douteuses.. L’association entre réactions positives et symptômes respira- toires n’était statistiquement pas significative (P>0.05). La tuberculose bovine a été reportée pour la première fois pour des zébus dans le système d’élevage traditionnel en Ethiopie. Le risque potentiel d’infection humaine avec M. bovis est discuté. MOTS-CLÉS : Mycobacterium bovis, intra-dermo tuber- culination, zébu, district de Boji, Ethiopie, zoonose. Revue Méd. Vét., 2004, 155, 10, 494-499 SUMMARY A study was conducted to determine the herd and individual animal pre- valence of bovine tuberculosis (BTB) in zebu cattle in Boji district in wes- tern Ethiopia. A total of 62 herds consisting of 780 heads of cattle were included in this study. Of the 62 herds, 35 were tested with single intra der- mal tuberculin test and another 27 herds with comparative intra dermal tuberculin test. The result of single intra dermal tuberculin test indicated a herd prevalence of 51% (18/35) and an individual animal prevalence of 4.1% (19/460). The herd prevalence was 19% (5/27) while the individual animal prevalence was 1.6% (5/320) with comparative intra dermal tuber- culin test, 2.2% (7/320) of the animals being doubtful. The association bet- ween positive reactions and respiratory symptoms was statistically not significant (P>0.05). BTB was reported in zebu cattle kept under traditional farming system for the first time in Ethiopia. On the basis of the results of the present study, the potential risk of infection of man with M. bovis is dis- cussed. KEY-WORDS : Mycobacterium bovis, intra dermal tuber- culin test, zebu cattle, Boji district, Ethiopia, zoonosis.