North American Crane Working Group


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Snyder, S. Bret, Michael J. Richard, and Carol U. Meteyer. Avian tuberculosis in a whooping crane: treatment and outcome. In: Urbanek RP, Stahlecker DW, eds. 1997. Proceedings of the Seventh North American Crane Workshop, 1996 Jan 10-13, Biloxi, Mississippi. Grand Island, NE: North American Crane Working Group. pp. 253-55.


Used by permission of the North American Crane Working Group.


A whooping crane (Grus americana) confirmed as suffering from Mycobacterium avium infection was treated for 1 year with daily doses of rifampin (45 mg/kg) and ethambutol (30 mg/kg) and 2 doses of M. vaccae antigen. Remission of disease occurred during therapy; however, recrudescence to active infection was suspected by 10 months after the antitubercular drugs were discontinued when the crane exhibited weight loss and had thickening of bowel wall as seen on radiographs. A second therapeutic regimen using azithromycin was then initiated (40 mg/kg fed daily) and was accompanied by a second remission within 6 weeks. After 16 weeks of azlthromycin therapy, ethambutol (30 mg/kg daily) was added to the azithromycin to reduce the probability of emergent drug resistance. Three weeks later the crane developed severe hepatic dysfunction as suggested by blood chemistry values. This contributed to the crane's collapse and eventual death. All tissues cultured were negative for M. avium infection. A severe hepatopathy and chronic fibrosing cardiomyopathy may have resulted from the drug combinations. This case suggests azithromycin as a promising therapeutic agent in treatment of avian tuberculosis and warrants further investigation.