Actinomycosis in Dogs

Actinomyces bacteria normally live in the mouth and throat. Several types can cause disease, called actinomycosis, in dogs:

• Actinomyces bovis can cause deep infection in the face, often involving bone. Disease usually starts when the bacteria are pushed deeper into the body through puncture wounds (for example, from sticks, sharp objects, or running through brush). This can lead to facial swelling, loose teeth, and trouble breathing if the nasal area swells. Bone infections can be hard to cure because antibiotics don’t penetrate bones well.

• Actinomyces hordeovulneris can cause abscesses (pockets of pus) and more widespread infections, including pus around the lungs, infection of the abdomen lining, abscesses in organs like the liver or spleen, and infected joints. This type of infection is often a result of the sharp tips of grasses working their way into the body through wounds and carrying bacteria in. Treatment usually requires surgery, plus long-term antibiotics.

• Actinomyces viscosus often causes abscesses under the skin after injuries like bite wounds, especially on the head, neck, chest, or abdomen. It can sometimes cause long-term lung infections or nervous system infection. Early treatment improves success, especially for chest infections. Skin abscesses that remain localized to a limited area, rather than spreading throughout the body, usually respond better to treatment.