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Pet Owner Version

Nocardiosis in Cats


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 Aug 2018 | Modified Oct 2022
Topic Resources

Nocardiosis is a longterm, noncontagious disease caused by the bacteria of the genus Nocardia. These bacteria are found commonly in soil, decaying vegetation, compost, dust, freshwater, saltwater, and other environmental sources. They enter the body through contamination of wounds (including those caused by punctures, foreign objects, or cat fights), ingestion, or by inhalation. In cats, the disease is often associated with an underlying immune system disorder (such as those caused by feline leukemia Feline Leukemia Virus (FeLV) Feline leukemia virus (FeLV) is one of the most important infectious diseases of cats worldwide. Affected cats can develop anemia (a low red blood cell level), cancers, and/or suppression of... read more or feline immunodeficiency virus Immunodeficiencies Caused by Viruses ).

Nocardia bacteria

Nocardia bacteria

Nocardia bacteria typically cause abscesses (pockets of pus and infection) in organs, skin infections, and pneumonia. Infections can also spread to multiple locations throughout the body. Poor appetite, fever, lethargy, and weight loss are common nonspecific signs associated with all infection sites. Infections in cats are often localized, with lesions beneath the skin, mycetomas, and inflammation of one or more lymph nodes. Skin infections and abscesses are mainly seen on the limbs, flank, nose, and neck. 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 can result in discharge from the eyes and nose, coughing (sometimes with blood), and trouble breathing. Nocardiosis that spreads throughout the body can produce abscesses in more than one organ, or severe pus-producing inflammation of the chest cavity (pleuritis or pyothorax) or abdominal cavity (peritonitis). The heart, liver, kidneys, and brain may also be affected.

Nocardiosis is diagnosed based on laboratory tests, especially bacterial cultures. Additional tests, such as chest x-rays or blood tests, may also be necessary depending on the area affected. Your veterinarian will prescribe antibiotics based on the results of the bacterial culture. Nocardial infections are resistant to some types of antibiotics. Treatment must often be continued for 1 to 6 months because relapses are common with shorter treatments. 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. Treatment is generally less successful when the infection is in the lungs or has spread throughout the body.

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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