Lumpy jaw is caused by bacteria normally found in the mouths of healthy animals.
The bacteria can enter through wounds in the mouth, which can be caused by coarse feed or when teeth break through the gums during development. Lumpy jaw can be found in ungulates such as sheep, caribou and moose throughout their range in Alaska. The disease does not spread between animals. Infection of the jaw bone itself causes firm swellings that can be quite large. Lumpy jaw may interfere with the animal s ability to eat.