An outbreak of avian tuberculosis in peafowl (Pavo cristatus) and pheasants (Phasianus colchicus) in a zoological aviary in Turkey

Avian tuberculosis was diagnosed histopathologically and microbiologically in two pheasants (Phasianus colchicus) and two peafowl (Pavo cristatus) kept in the same aviary. The incidence of avian tuberculosis in the aviary was 6%. Non-mineralized caseogranulomas were present in the liver (3 cases), spleen (3 cases), intestine (2 cases), lung (2 cases), and cloaca (1 case). Granulomas in the lung were present only in peafowl. The presence of granulomas in the lung of both infected peafowl suggests that peafowl were exposed to the agent via the respiratory route rather than the alimentary route. Histopathologic findings were typical of avian tuberculosis, including acid fast bacilli and centrally located caseo-necrosis surrounded by epitheloid macrophages, lymphocytes, and multinucleated giant cells. Mycobacterium avium subsp. avium was isolated from tissue samples of all infected birds.