Disseminated nontuberculous mycobacteriosis due to Mycobacterium avium subsp. hominissuis infection in a reindeer from a zoo

Bacteria in the Mycobacterium tuberculosis complex and nontuberculous mycobacteria may affect a variety of animal species under human care and pose public health risks as zoonotic pathogens. A case of sudden onset of lethargy and increased respiratory effort in a 5-y-old, intact female reindeer (Rangifer tarandus) under managed care had progressed to severe dyspnea despite aggressive treatment. The animal was euthanized due to poor prognosis. Postmortem findings included: disseminated miliary nodules in the lungs, pleura, small intestine, liver, and spleen; enlarged mesenteric lymph nodes; dilated mesenteric and serosal lymphatic vessels; and renal infarcts. Histologically, granulomatous lymphadenitis and lymphangitis with intrahistiocytic acid-fast bacilli were observed. Mycobacterium sp. DNA was detected in lung via real-time PCR. Mycobacterial culture and sequencing identified Mycobacterium avium subsp. hominissuis (MAH) within pulmonary lesions. Infection with MAH has been reported in humans and many animal species; this nontuberculous mycobacterial infection may be an emerging concern in animals under managed care. To our knowledge, MAH infection has not been reported previously in reindeer.