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

The study divulges details of a case report where a 10-year old Freiberger mare was infected with Mycobacterium avium subsp. avium, causing symptoms similar to tuberculosis, specifically affecting the intestines and lungs. The study highlighted the challenges of diagnosis due to these overlapping symptoms with other diseases and suggested the need to consider this infection in the differential diagnosis of granulomatous diseases.

Objective of the Report

• The primary aim of the study was to present a case report on a Freiberger mare infected with Mycobacterium avium subsp. avium, which typically leads to a disease with similarities to tuberculosis, largely affecting the animal’s intestines and lungs. Though rare in Central European horses, the report calls attention to its existence and diagnostic challenges.

Observations and Findings

• The horse showed characteristics of diarrhea, mastitis, neck stiffness, dyspnea (difficult or labored breathing), and chronic cough, which are unique to this infection.
• Generic signs like weight loss, weakness, and lethargy were also reported, which were considered non-specific as these might be symptoms of other diseases.

Diagnosis of the Disease

• Due to the complex nature of the symptoms, it was concluded that diagnosing this type of mycobacterial infection is challenging. The reported symptoms can be found in many other diseases which add a layer of complexity in diagnosing this particular infection.
• However, important measures taken for proper diagnosis consist of biopsies from the rectum or distal colon and staining for acid-fast bacilli.
• Additionally, a bacteriological culture of the granulomatous lesions that the infection generates was also considered imperative for the diagnosis.
• The correct classification of M. avium subsp. avium was achieved through a technique known as PCR-RFLP (Polymerase Chain Reaction – Restriction Fragment Length Polymorphism).

Conclusion of the Report

• The report suggested that while Mycobacterium avium subsp. avium infection is relatively rare, it should be included in the differential diagnosis of granulomatous diseases due to its significant potential to cause severe illness in horses.