Avian mycobacteriosis in captive brolgas (Antigone rubicunda).

CASE SERIES: Avian mycobacteriosis is a significant disease of a wide range of bird species worldwide. The most common causative agent, Mycobacterium avium, is reported to also infect a range of mammals, including humans. Of 11 brolgas (Antigone rubicunda) submitted to the University of Melbourne for postmortem examination over a 10-year period, 7 were diagnosed with mycobacteriosis. All were from a wildlife park and kept in permanent enclosures as part of a breeding program. Most of the brolgas with mycobacteriosis were in poor body condition and had widely disseminated granulomas throughout the body, especially within the liver, spleen and gastrointestinal tract. Respiratory tract involvement was common, with all disseminated cases having pulmonary or air sac granulomas. Rare to moderate numbers of acid-fast organisms were detected in granulomas by histological examination. Where examined by appropriate bacteriological examinations, M. avium complex was isolated from affected tissues. CONCLUSION: This case series is the first known report of mycobacteriosis in brolgas and highlights the pathological changes seen. The complications in maintaining an avian mycobacteriosis-free breeding program and in eradication of the disease from an enclosed wildlife environment are discussed.

Effect of different cell fractions of Mycobacterium avium and vaccination regimens on Mycobacterium avium infection.

Because of the availability of uniform genetic stocks and the ability to modulate stress levels, chickens were investigated as a host for the development of an antimycobacterial vaccine. The imposition and the timing of stress significantly influenced the outcome of Mycobacterium avium infection in chickens. Simple, whole cell or lysate vaccines and combinations of vaccine preparations were identified that led to high levels of protection. In addition, short-term stress at the time of vaccination significantly increased the protective efficacy of M. avium vaccine preparations. Post-infection vaccination of M. avium-infected chickens was also shown to significantly reduce the number of lesions and colony counts.

Mycobacterium avium infections in animals. Literature review.

Mycobacterium avium causes tuberculosis in chickens and other fowls but can also infect an extensive range of different animal species. The authors reviewed the available literature on this organism to show the importance of M avium infection.