Bovine tuberculosis in Ethiopian wildlife

Bovine tuberculosis (BTB) is endemic in Ethiopian cattle. However, the status of the disease in wildlife populations that often share habitat with livestock is unknown. We screened for BTB in wildlife in five regions in Ethiopia. Blood and tissue samples from 133 mammals of 28 species were collected from 2006 to 2008. We used a rapid serology test (RT) based on lateral flow technology, and performed culture of lymph node specimens inoculated onto Lowenstein-Jensen and Middlebrook 7H11 media. Acid-fast colonies were further analyzed by molecular typing. Sera from 20 of 87 animals (23%) were positive for BTB by RT; acid-fast bacilli were cultured from 29 of 89 animals (32.5%). None of the positive cultures yielded mycobacteria from the Mycobacterium tuberculosis complex but many environmental mycobacteria were isolated. Among these, Mycobacterium terrae was the most common. We demonstrated a high prevalence of environmental mycobacteria in wildlife, the role of which is unknown. Flagship rare endemic species such as the mountain nyala (Tragelaphus buxtoni) and the Ethiopian wolf (Canis simensis) may be at risk for BTB. We also assessed the utility of RT for field purposes.