Tuberculosis is an infectious disease caused by bacteria of the genus Mycobacterium. The disease affects practically all species of vertebrates, and, before control measures were adopted, was a major disease of humans and domestic animals. Signs and lesions are generally similar in the various species. Tuberculosis is uncommon in cats in North America.

Three main types of tubercle bacilli are recognized: human (Mycobacterium tuberculosis), bovine (Mycobacterium bovis), and avian (Mycobacterium avium). Cats are quite resistant to the human form.

Ingestion, particularly via contaminated food or milk, is the most common source of infection. The baceria may spread rapidly through the bloodstream and lymphatic channels and cause death. Alternatively, a prolonged course of disease may ensue. The signs reflect the extent and location of infection plus the underlying condition caused by the spread through the bloodstream. Generalized signs include lethargy, weakness, loss of appetite and weight, and fever. The pneumonia of the respiratory form of the disease causes a chronic, intermittent, moist cough with later signs of difficulty breathing and quick, shallow breathing.

The tuberculin skin test for diagnosis is considered unreliable in cats. Treatment of tuberculosis in cats is often not successful. If a cat is suspected of having advanced tuberculosis, it must be reported to the appropriate public health authorities. It is generally recommended that affected cats be euthanized.

Last full review/revision July 2011 by Otto M. Radostits, CM, DVM, MSc, DACVIM (Deceased); Eugene D. Janzen, DVM, MVS; Jodie Low Choy, BVMS; Dennis W. Macy, MS, DACVIM; Dudley L. McCaw, DVM, DACVIM (Small Animal, Oncology); Barton W. Rohrbach, VMD, MPH, DACVPM; J. Glenn Songer, PhD; Richard A. Squires, BVSc (Hons), PhD, DVR, DACVIM, DECVIM-CA, MRCVS; Bert E. Stromberg, PhD; Joseph Taboada, DVM, DACVIM; Charles O. Thoen, DVM, PhD; John F. Timoney, MVB, PhD, Dsc, MRCVS; Ian Tizard, BVMS, PhD, DACVM; Max J. Appel, DMV, PhD; David A. Ashford, DVM, MPH, DS; Stephen C. Barr, BVSc, MVS, PhD, DACVIM; J. P. Dubey, MVSc, PhD; Paul Ettestad, DVM, MS; Craig E. Greene, DVM, MS; Delores E. Hill, PhD; Johnny D. Hoskins, DVM, PhD