Tuberculosis in captive exotic birds.

Avian tuberculosis was studied clinically and pathologically in 137 affected birds from the National Zoological Park during a 7-year period (1969-1975). Twelve of 22 orders exhibited were affected by the disease, and the highest annual mortality was 4% (in 1975). Antemortem diagnosis of early cases of the disease, based on tuberculin testing, and serologic, hematologic, and radiographic studies, was inconsistent and often not conclusive. Pathologically, the diseases primarily involved digestive organs and spleen. There was a spectrum of lesions consisting of nodules of large foamy histiocytes packed with acid-fast bacilli to giant cell-containing granulomas that were often caseous but not cavitated or calcified. Amyloidosis was seen in approximately 20% of the cases. Mycobacterium avium serotype 1 was isolated from 30 tuberculous birds cultured. There was no sex predilection, and most of the affected birds were adults ranging from 1 to 10 years of age.