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(undulant fever, Bang's disease)

Brucellosis is a bacterial disease that may affect various organs of the body, producing a wide variety of signs and symptoms such as intermittent fever of variable duration, headache, weakness, swollen lymph nodes, profuse sweating, chills, weight loss and generalized aching. Brucellosis can also cause infection and inflammation of the bone, testicles, and the lining of the heart.

Brucellosis 101

Brucellosis is generally transmitted from infected animals (cattle, goats, pigs, and dogs) to humans and occurs more commonly outside the USA and Canada. Wisconsin averages only about one to two cases per year. Although everyone is susceptible and may get the disease if exposed to the Brucella bacteria, brucellosis occurs most commonly in people who work with livestock or in slaughterhouses, or who consume unpasteurized dairy products. The consumption of raw milk cheese from Mexico is a well-recognized risk factor. Occasionally, persons who work in bacteriology laboratories can get exposed to the bacteria.

Brucellosis can cause of range of signs and symptoms, some of which may present for prolonged periods of time.

Initial symptoms can include:

  • Fever
  • Sweats
  • Malaise
  • Anorexia
  • Headache
  • Pain in muscles, joint, and/or back
  • Fatigue

Some signs and symptoms may persist for longer periods of time. Others may never go away or reoccur.

These can include:

  • Recurrent fevers
  • Arthritis
  • Swelling of the testicle and scrotum area
  • Swelling of the heart (endocarditis)
  • Neurologic symptoms (in up to 5% of all cases)
  • Chronic fatigue
  • Depression
  • Swelling of the liver and/or spleen

Before treatment begins, a diagnosis of brucellosis infection must be made by a doctor.

Tests will be performed to look for bacteria in samples of blood, bone marrow, or other body fluids. In addition, a blood test can be performed to detect antibodies against the bacteria.

Once a diagnosis is made, a doctor can prescribe antibiotics.

Depending on the timing of treatment and severity of illness, recovery may take a few weeks to several months. Death from brucellosis is rare, occurring in no more than 2% of all cases.

The best way to prevent brucellosis infection is to be sure you do not eat or drink:

  • Undercooked meat
  • Unpasteurized dairy products, including:
    • Milk
    • Cheese
    • Ice cream

Pasteurization is when raw milk is heated to a high temperature for a short period of time. This heating process destroys harmful bacteria that may make the milk unsafe to drink.

If you are not sure that the dairy product is pasteurized, do not eat or drink it.

People who handle animal tissues (such as hunters and animal herdsman) should protect themselves by using:

  • Rubber gloves
  • Goggles
  • Gowns or aprons

This will help ensure that bacteria from potentially infected animals do not get into eyes or inside a cut or abrasion on the skin.

Brucellosis fact sheet, P-42033

Provider Information

This is a Wisconsin disease surveillance category II disease:

Wisconsin case reporting and public health follow-up guidelines:

Case Reporting and Investigation Protocol (EpiNet): P-01902 Brucellosis (PDF)

Brucellosis Case Report Form - CDC

Questions about Brucellosis? Contact us!
Phone: 608-267-9003 | Fax: 608-261-4976

Wisconsin Local Health DepartmentsRegional officesTribal agencies

Last revised October 7, 2021