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.

Three main types of tubercle bacilli are recognized: human (Mycobacterium tuber-culosis), bovine (Mycobacterium bovis), and avian (Mycobacterium avium). The 2 mammalian types are more closely related to each other than to the avian type. Each of the types may produce infection in other host species.

The breathing in of infected droplets expelled from the lungs of an infected person or animal is the usual—though not the only—route of infection. Ingestion, particularly via contaminated food or milk, may also be a common source of infection.

Most infected dogs do not have any signs, as the canine immune system actively suppresses the bacteria. When disease does occur, signs generally include chronic coughing with difficulty breathing or quick, shallow breaths. Other generalized signs include progressive emaciation, lethargy, weakness, poor appetite, and a low-grade, fluctuating fever.

The disease is easily transmitted to humans and other animals and represents a public health risk. Therefore, treatment of tuberculosis in dogs should be discussed with your veterinarian. If a dog is suspected of having advanced tuberculous lesions, it must be reported to the appropriate public health authorities, and the dog should be euthanized.

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