Detection and anatomopathological description of tuberculosis in an Ankole-Watusi colony

Abstract

The purpose of this study was to detect tuberculosis (TB)-infected animals in a captive Ankole-Watusi colony using tuberculin test, bacterial isolation and identification, and describing the anatomopathological findings at posting. Double, comparative tuberculin intradermal test (CTIT) was applied to 15 watusis. One animal was a positive reactor while other two were suspicious. All three animals were killed in the search of lesions. Samples were collected for histopathology and bacteriology. At postmortem examination, two animals showed lesions consistent with TB, with purulent exudate in both lymph nodes and lungs. Mycobacterium bovis was isolated from the animals that showed gross lesions. HE-stained histopathological preparations from the affected tissues showed lymphadenitis and pyogranulomatous pneumonia. Using ZN stain, scarce acid-alcohol resistant bacteria were observed. CTIT showed to be a useful diagnostic tool in this particular species in order to detect sick animals and to correlate growth lesions at necropsy with histopathology and bacterial isolation. Abscess-like TB lesions are commonly found in deer and other wild animals, but these have also been described in cattle. Such lesions are likely common in Ankole watusi as well. Captive wild animals should be routinely subjected to TB diagnostic procedures for the early detection of infected animals, since they are potential reservoirs for domestic cattle, other captive wild animals, and very importantly, for humans.