Nocardiosis in Dogs

Nocardiosis is a long-term, bacterial infection caused by Nocardia bacteria. These organisms are commonly found in soil, decaying plants, and other environmental sources. Infection usually occurs when bacteria enter the body through skin wounds (such as bites or injuries involving plant material), contaminated cuts, or, less commonly, by inhalation. This infection is not contagious (spread from animal to animal).

Dogs with weakened immune systems are at higher risk, including those with diseases like canine distemper. The condition can occur at any age but is seen most often in young adult male dogs.

In dogs, nocardiosis most commonly affects the skin, lymph system, and chest. It can also spread to multiple organs in the body. General signs include fever, weakness, poor appetite, and weight loss.

Infections can form under the skin, cause swollen lymph nodes, or produce tumorlike masses in the skin or underneath it. Some dogs develop inflammation and ulcers of the gums with severe bad breath.

Infections might involve the chest or abdomen. Infection can spread to the heart, liver, kidneys, spleen, eyes, bones, joints, urinary tract, or brain. Rarely, inhaled bacteria can cause a severe, rapidly spreading disease throughout the whole body.

Diagnosis is made using bacterial culture, and imaging (like x-rays) might be needed. Treatment involves antibiotics selected based on culture results, because Nocardia can be resistant to some drugs. Therapy is usually long-term, lasting 1–6 months, and surgery might be required to eliminate the infection. Even with treatment, relapse is possible, so the outlook is often guarded.

Nocardiosis can also affect people, especially those with weakened immune systems. People at risk should avoid contact with contaminated soil, cover skin wounds, and be cautious around animals suspected of infection.