Investigation and Diagnosis of Nontuberculous Mycobacteriosis in a Captive Herd of Aoudad (Ammotragus lervia)

An epizootic of nontuberculous mycobacteriosis occurred in a captive herd of aoudad (Ammotragus lervia) over a period of 18 mo. Each of the affected animals was subject to a thorough postmortem examination that included histopathology, tissue concentration and acid-fast staining, aerobic and anaerobic bacterial culture, mycobacterial culture, and real-time polymerase chain reaction specific for Mycobacterium tuberculosis DNA. Histopathologic lesions consistent with pulmonary mycobacteriosis, including the presence of acid-fast bacteria, were identified in two captive adult male aoudad. M. avium was isolated in culture from the pulmonary parenchyma, and M. parafortuitum was isolated from a mesenteric lymph node of a third animal, an adult female, euthanized subsequent to an illness characterized by progressive dyspnea and tachypnea. M. intracellulare was isolated within the bronchial lymph node of a fourth aoudad, an adult female that was euthanized due to chronic weight loss. Diagnostic testing of the 34 individuals in the herd included collection of blood for an interferon-γ assay, intradermal tuberculin testing, and radiometric fecal culture for M. avium subsp. paratuberculosis. On the basis of this investigation, mycobacteriosis associated with M. bovis, M. tuberculosis, and/or M. avium subsp. paratuberculosis was ruled out and nontuberculous mycobacteriosis was confirmed in this herd.