Lumpy Jaw in Hamsters

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Actinomycosis in Hamsters


Actinomycosis is a rare infectious disease caused by gram positive, rod-shaped bacteria of the genus Actinomyces; more specifically, the A. bovis species. This bacterium is a common inhabitant of a hamster's mouth. It is only when the animal has an open wound in the mouth that the bacteria is able to enter the bloodstream and cause a widespread infection. This can lead to inflammation and softening of the jawbones, hence the more common name of the disease: “Lumpy Jaw.”




In the initial stage of actinomycosis, the hamster experiences respiratory difficulties. The heart rate and pulse rate will increase, and the skin may become bluish. In the later stages, pus-filled pockets (abscesses) inside the salivary glands will burst, causing swelling, especially in the jaw region. The jaws will become swollen until the hamster is unable to eat, which leads to weight loss.




Actinomycosis in hamsters is due to the bacteria Actinomyces bovis, which gains entry into the body through wounds present in the mouth.




You will need to give a thorough history of your hamster’s health, including the onset and nature of the symptoms, to the veterinarian. He or she will then perform a complete physical examination.


For a more definitive diagnosis your veterinarian will submit a specimen of pus for culturing. Gram staining, cytology, and acid-fast staining may also be employed.