Parasites and Diseases

A Field Guide


swollen knee joint
Swollen caribou “knee” joint due to brucellosis.

What causes brucellosis?

  • Brucellosis is a highly contagious disease caused by bacteria called Brucella suis type 4 in caribou and reindeer. It is spread in the afterbirth and fluids during calving.

Where does brucellosis occur?

  • Brucella suis occurs naturally in caribou and reindeer and has also been seen in muskoxen and moose.
  • Brucella is most common in the four arctic caribou herds (Western Arctic, Teshekpuk, Central Arctic and Porcupine herds). Predators such as bears and wolves are exposed when they feed on infected caribou.
  • Humans can be infected by Brucella suis type 4.

What are the signs of brucellosis?

  • Animals may appear healthy and not show any signs of disease.
  • Brucellosis usually affects the reproductive organs and leg joints.
  • Often, animals will have swollen leg joints causing limping or lameness (especially in the front legs).
  • When butchering, you may find pus-filled swellings under the skin, in the meat or in the internal organs.
  • The testicles or womb may be swollen.
  • In people brucellosis often causes a high fever that frequently comes and goes.

How can I protect myself? [can infect people]

  • You can get brucellosis through exposure to contaminated parts. The bacteria can enter through cuts or scratches in your skin or through your eyes, nose or mouth. You can also get brucellosis by eating infected meat that has not been fully cooked.
  • Do not cut into diseased parts.
  • Do not spill fluid from the womb onto the meat.
  • Use extreme care when handling any fetal membranes or aborted tissues.
  • Wash your hands, knives and clothes with hot soapy water after handling the animal.
  • Report any animals suspected of having brucellosis to your nearest ADF&G biologist.

Can I eat the meat? [can infect dogs]  [cook well]

  • Meat from animals with brucellosis should be thoroughly cooked.
  • Freezing, smoking, drying and pickling do not kill Brucella.
  • Raw bone marrow from infected animals can contain the bacteria.
  • Do not feed diseased parts to dogs.

Do not collect samples, Photos only please