Lung tuberculosis in a horse caused by Mycobacterium avium subsp. avium of serotype 2: a case report

Abstract

Interstitial pneumonia (2/3 of the lungs were affected) and diffusely enlarged bronchial and mediastinal lymph nodes were diagnosed by gross examination of a dead 16-year-old mare. Based on histopathological examination and the detection of acid-fast rods after staining by the Ziehl-Neelsen technique, tuberculosis was suspected. Mycobacterium avium subsp. avium of serotype 2 and IS901+/IS1245+ genotype was isolated from the pulmonary lymphnode after five-week incubation at 37°C. Due to the fact that horses have a naturally high resistance to mycobacterial infections, the high age of the mare most likely contributed to the development of the disease.