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Pet Owner Version

Nocardiosis in Dogs


Márcio Garcia Ribeiro

, DVM, PhD, Department of Animal Production and Preventive Veterinary Medicine, Faculty of Veterinary Medicine and Animal Science, São Paulo State University (UNESP), Botucatu, SP, Brazil

Reviewed/Revised Jun 2018 | Modified Oct 2022

Nocardiosis is a longterm, noncontagious disease caused by the bacteria of the genus Nocardia. These bacteria are found commonly in soil, decaying vegetation, compost, and other environmental sources. They enter the body through the skin after an injury (such as dog bites or migrating plant material), contamination of wounds, or rarely by inhalation. Nocardiosis is more likely in dogs with underlying disorders that suppress the immune system, for example, dogs infected by distemper virus. The disease occurs at any age and in both sexes, although it appears to affect mainly males, particularly those 1 to 2 years old.

Nocardiosis in dogs most often causes infections of the skin, lymph system, and chest. It can also spread throughout the body and cause infections in multiple internal organs. Poor appetite, fever, lethargy, and weight loss are common nonspecific signs associated with all infection sites. Infections in dogs are often localized, with lesions beneath the skin, mycetomas (infections of the skin and underlying tissues that have the appearance of nodules or tumors), and inflammation of one or more lymph nodes. There may be swelling and inflammation of the gums around the teeth and ulcers in the mouth accompanied by severe bad breath. Nocardiosis affecting the chest often involves pus-producing inflammation of the chest cavity or abdominal cavity, or infection in the lungs. The heart, liver, kidneys, spleen, eyes, bones, joints, urinary tract, and brain may also be affected. Occasionally, young dogs have a form of disease that begins in the lower respiratory tract after inhalation of the organism and spreads throughout the body.

Bacterial cultures are used to diagnose nocardiosis. Other tests, such as x-rays, may also be necessary, depending on which part of the body is affected. Your veterinarian will prescribe antibiotics based on identification of the bacteria. Nocardial infections are resistant to some types of antibiotics. Treatment must often be continued for 1 to 6 months. Surgery to remove infected tissue may also be appropriate. Any underlying diseases also need to be addressed. It is important to continue treatment as directed to allow your pet the best possibility for recovery. The prognosis is guarded due to the long treatment time and the likelihood of relapse.

Nocardiosis can occur in people, especially those with immune system dysfunction or a debilitating disease. At-risk individuals should take precautions regarding contact with soil in areas used by animals, contamination of skin wounds, or close contact with animals suspected of having nocardiosis.

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