Lumpy jaw is a disease of the jawbone caused by a bacterial infection called Actinomyces bovis. These bacteria form part of the normal flora in the mouth of ruminants. So then how does it cause disease? The bacteria enter the soft tissue of the mouth through open wounds. These wounds can be caused by foreign objects such as sticks, wire, thorns, or grass awns. Very coarse feed has also been known to cause injury to the soft tissue of the mouth.
True to its common name, this bacterium produces permanent hard swellings on the bones of the jaw. The bottom jawbone, the mandible, is more commonly affected. The swellings are multiple pus-filled abscesses attached to the bone. The by-products produced by this bacterium start to break down the bone of the jaw – forming little pits in the bone. The body tries to compensate for this loss by laying down new bone. This is how these swellings become permanent. The bone affected by this bacterium has a very characteristic honeycomb appearance. These swellings cause facial distortion, loss of teeth, and difficulty breathing as they obstruct the airway.
Animals do not die from the bacterium directly but rather the consequences of it. Animals affected by this bacterium are unable to eat or drink properly resulting in poor condition.
Lumpy jaw is not a highly contagious disease, often only one to two are affected. Animals can be treated but unfortunately, any bony changes to the jaw cannot be reversed. The bacterium is killed by treating the animal with sodium Iodide intravenously once a week for several weeks. Relapse of this condition is common.
