Questions and Answers
January, 2000
The disease Tularemia, or Rabbit Fever, is caused by a tiny
but dangerous bacteria called Francisella tularensis. The disease
most commonly affects wild rabbits and rodents, but can also be
transmitted to people and domestic animals. Several species of
ticks are known vectors of this disease. It has a worldwide
distribution, and in the U.S. its most common in the Midwest and
Southwest.
It is not commonly diagnosed in dogs, but when it does occur, the
clinical signs depend on how the animal was exposed. If infected
by eating contaminated raw rabbit meat, sores can occur in the
mouth and throat. Ulcers and abscesses of the skin can be seen
when bitten by an infected animal or by a tick carrying the
organism. Apparently, the bacteria can burrow into the skin with
just incidental contact and no bite wound at all. When airborne,
the organism can cause infection in the eyes or respiratory
tract, including the lungs. Regardless of the route of exposure,
some common signs include fever, poor appetite, listlessness and
enlarged lymph nodes. If treated early,the disease can respond to
antibiotics.
The disease is seen more frequently in people than in dogs,
although it still uncommon, with only about 200 cases per year
diagnosed in the U.S. When it causes pneumonia, the mortality
rate can be as high as 30%. As with dogs, affected humans can be
cured with early antibiotic therapy. If treatment is delayed,
however, relapses of the disease are seen. A vaccine is available
for those at risk, such as hunters, trappers and game wardens.