Infection with Mycobacterium avium subspecies avium in a 10 year old Freiberger mare.

In this case report a 10 year old Freiberger mare with a Mycobacterium avium subsp. avium infection is presented. This infection leads to a tuberculosis like disease with granulomatous alterations particularly of the intestines and lungs and is only sporadically reported in horses of Central Europe. Diarrhoea, mastitis and neck stiffness as well as dyspnoea and chronic cough are more specific symptoms of the infection, while weight loss, weakness and lethargy are nonspecific signs. As these clinical signs can occur in many other diseases, the diagnosis of mycobacterial infection is difficult and consists of rectum or distal colon biopsies and staining for acid-fast bacilli and bacteriological culture of granulomatous lesions. Classification of M. avium subsp. avium was achieved by PCR-RFLP. Even though an infection with Mycobacterium avium subsp. avium is rare, it belongs to the differential diagnosis of granulomatous diseases.