It is more commonly associated with animals than with humans.
One of the most common forms seen by veterinarians is mouth actinobacillosis of cattle, due to Actinobacillus lignieresii. The most prominent symptom is the swelling of the tongue that protrudes from the mouth and is very hard at palpation ("wooden tongue").
The infection is most commonly caused by abrasions on different soft tissues through which the bacteria, Actinobacillus lignieresii, enters. These soft tissues include subcutaneous tissues, the tongue, lymph nodes, lungs, and various tissues in the gastrointestinal tract. The injury results in different forms and locations of the disease depending on the location of the tissue. The commensal bacteria is also commonly found in the oral cavity, gastrointestinal tract, and reproductive tract, sometimes resulting in disease. There are generally one or two cases of actinobacillosis per herd found in adult cows, foals or adult horses, and other similar animals.
Mouth actinobacillosis of cattle must be differentiated from actinomycosis that affects bone tissues of the maxilla.