Mycobacterium avium subsp. hominissuis Infection in a Captive-Bred Kiang (Equus kiang)

Equids are considered highly resistant to mycobacterial infections and clinical cases have been described in domestic horses only. Mycobacterium bovis is the most common species reported, although a single report exists of disease due to definitively diagnosed infection with Mycobacterium avium subsp. hominissuis in two domestic horses. This is the first report of a mycobacterial infection in a kiang (Equus kiang), or indeed any wild equid. The animal had chronic loss of condition and serum biochemical changes suggestive of liver disease and chronic infection. Further investigation showed a chronic granulomatous enteritis, lymphadenitis and hepatitis with focal granulomatous pneumonia due to systemic infection with M. avium subsp. hominissuis. The distribution and severity of the lesions suggested that the route of infection was alimentary.