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Veterinary Medicine International
Volume 2012, Article ID 642145, 6 pages
Research Article

Pulmonary Disease due to Mycobacterium tuberculosis in a Horse: Zoonotic Concerns and Limitations of Antemortem Testing

1Research and Development Department, Chembio Diagnostic Systems, Inc., 3661 Horseblock Road, Medford, NY 11763, USA
2Museum National d'Histoire Naturelle Department, Paris Zoo, 53 Avenue de Saint-Maurice, 75012 Paris, France
3Infectious Bacterial Diseases Research Unit, National Animal Disease Center, Ames, IA 50010, USA
4Institute of Animal Pathology, Vetsuisse Faculty, University of Bern, P.O. Box 8466, 3001 Bern, Switzerland
5Institute for Infectious Diseases, Medical Faculty, University of Bern, 3010 Bern, Switzerland
6Division of Pulmonary Diseases, Geneva University Hospitals, 1211 Geneva, Switzerland
7Equine Clinic, Vetsuisse Faculty, University of Bern, P.O. Box 8466, 3001 Bern, Switzerland
8Cantonal Veterinary Office Geneva, Quai Ernest-Ansermet 22, Plainpalais P.O. Box 76, 1211 Geneva 4, Switzerland
9Monitoring Department, Swiss Federal Veterinary Office, Schwarzenburgstrasse 155, 3003 Bern, Switzerland

Received 21 December 2011; Accepted 3 February 2012

Academic Editor: Mitchell Palmer

Copyright © 2012 Konstantin P. Lyashchenko et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A case of pulmonary tuberculosis caused by Mycobacterium tuberculosis was diagnosed in a horse. Clinical evaluation performed prior to euthanasia did not suggest tuberculosis, but postmortem examination provided pathological and bacteriological evidence of mycobacteriosis. In the lungs, multiple tuberculoid granulomas communicating with the bronchiolar lumen, pleural effusion, and a granulomatous lymphadenitis involving mediastinal and tracheobronchial lymph nodes were found. Serologic response to M. tuberculosis antigens was detected in the infected horse, but not in the group of 42 potentially exposed animals (18 horses, 14 alpacas, 6 donkeys, and 4 dogs) which showed no signs of disease. Diagnosis of tuberculosis in live horses remains extremely difficult. Four of 20 animal handlers at the farm were positive for tuberculous infection upon follow-up testing by interferon-gamma release assay, indicating a possibility of interspecies transmission of M. tuberculosis.