Lumpy Jaw
Causative Agent

  • Lumpy jaw is the result of an infection of the jawbone with the bacteria, Actinomyces bovis.

  • A. bovis is a bacterium that is normally found in the mouths of healthy animals.

  • Bacteria may enter small wounds in the mouth, caused by tooth eruption or by coarse feed.

Click on the photo to enlarge.

Swelling of the jaw bone subsequent to bacterial infection causes the formation of conspicuous "lumps".

Distribution

Geographic and Seasonality:

  • Can occur throughout the year and throughout BC.
Hosts and Life Cycle

  • Occasionally found in wild ungulates such as white-tailed deer, mule deer, moose, caribou and mountain sheep.

Signs and Symptoms

  • Once bacterial infection is established, bacterial by-products break down existing bone and promote the growth of new bone – consequently, affected areas of the jaw expand forming “lumps” or thickened areas of bone, honeycombed with tiny abscesses.

  • Tissues within the mouth may become swollen and there can be spread to nearby areas of the mouth.

  • Difficulty chewing.

  • Tooth loss and impacting of feed usually occurs in affected areas.

  • Other than lesions in the mouth, animals may appear healthy but are often thin since jaw lesions may interfere with the ability to eat.
Transmission
  • This disease does not normally spread from animal to animal, but draining wounds can spread bacteria on common feed sources.

Meat Edible?

  • Affected areas of the jaw should not be consumed – otherwise, the rest of the carcass is suitable for human consumption.

Human Health Concerns and Risk Reduction

  • Although “lumpy jaw” cannot be contracted from animals, care should be taken not to cut into the swellings of the jaw as pus can spread and contaminate other parts of the carcass.

Samples for Diagnosis

  • Lower jaw and surrounding tissue.

Further Reading

Wobeser, G. 2001. Actinomyces and Arcanobacterium infections. Pp. 487-488 in E.S. Williams and I. K. Barker (eds.), Infectious Diseases of Wild Mammals. 3rd Ed. Iowa State University Press, Ames, IA.

Elkin, B, and R. L. Zamke. 2001. Common wildlife diseases and parasites in Alaska. Alaska Department of Fish and Game. Anchorage, AK.

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