Objective: Mycobacteriosis is an important disease of captive and wild Gouldian finches (Erythrura gouldiae). The aim of this study was to assess Gouldian finches from the Adelaide Zoo for mycobacteriosis and determine pathological features of the disease in this population.
Methods: Post-mortem examination was performed on 11 finches culled for the purpose of diagnostic investigations, and on 16 finches following natural death. Tissues from major organs were processed for histopathology using standard techniques, and further staining with Ziehl-Neelsen, Periodic Acid-Schiff and gram stains was performed as indicated. Finches showing granulomatous inflammation associated with intracellular acid-fast bacilli (AFB) were considered positive for mycobacteriosis.
Results: In total, 27 finches have been examined, and 10 birds have confirmed mycobacterial infection. Gross lesions were rarely identified, however histopathological examination revealed granulomatous lesions in the liver and intestines of all infected birds. Intracellular AFB were found in the liver of 8/10 and intestine of 5/10 birds, and less frequently, granulomatous foci containing AFB were present in the heart, lungs, spleen, proventriculus and ventriculus. Other diagnoses included fungal (Candida spp., Macrorhabdus ornithogaster) ventriculitis or proventriculitis in 7/27 birds, apical protozoal infection consistent with Cryptosporidium spp. in 3/27 birds, and hepatic amyloidosis in 2/27 birds.
Conclusions: Mycobacteriosis is present in Gouldian finches at Adelaide Zoo as well as a number of other opportunistic pathogens. These findings complement previous work suggesting that Gouldian Finches may have a decreased immunocompetence caused by environmental factors or inbreeding. Research outcomes will guide further work examining for immunosuppression in captive finches and aid in the implementation of management strategies in zoos.