MAC is a type of tuberculosis and is believed to be zoonotic. Miniature Schnauzers have a genetic predisposition to MAC infection.
Very young children, immune-compromised adults and elderly people are thought to be most at risk. However, there has been no case where the condition has been transmitted by a dog to a human.
The primary clinical sign of MAC infection is lymph node enlargement. The organisms infiltrate the liver and spleen, resulting in liver and spleen enlargement.
Other clinical signs include lethargy, vomiting, lack of appetite, fever, lameness, blood in the stool, diarrhoea, pale mucous membranes, abdominal distension and eye or nasal discharge.
Diagnosis can be achieved via a lymph node biopsy or aspirate performed with an acid-fast stain to identify cellular changes characteristic of mycobacterial infection.
The condition is usually fatal at a very early age.