Brucellosis is a disease that is spread to humans through contact with infected animals or contaminated animal products. It is most commonly spread by eating or drinking unpasteurized milk, cheese, and other dairy products. Brucellosis can usually be treated. However, it can be life-threatening if the infection leads to inflammation of the heart (endocarditis) or linings of the brain (meningitis). For some people, brucellosis can become a long-lasting (chronic) disease.


Brucellosis is caused by a bacteria of the genus Brucella. Humans become infected when they come in contact with animals or animal products that are infected or contaminated with these bacteria. Dairy products that are made with unpasteurized milk are the most common source of this bacteria. Pasteurization is the process of heating and quickly cooling milk to kill bacteria. Brucellosis is found worldwide, but it is more common in less developed places such as Mexico, other Central and South American countries, Asia, and Africa. Pasteurization of dairy products in these countries is not as universal as it is in the United States, Canada, and Western Europe.

Animals that can carry the bacteria include:

  • Sheep.

  • Goats.

  • Cattle.

  • Deer.

  • Elk.

  • Pigs.

  • Dogs.

Less commonly, the bacteria can enter the body through a skin wound or inhalation. People at risk for this type of infection include:

  • Lab workers.

  • Slaughterhouse or meat packing plant workers.

  • Veterinarians.

  • Hunters.

Very rarely, has brucellosis been passed from an infected mother to her child during breastfeeding, from an infected person to another person during sexual contact, and after receiving a blood transfusion or bone marrow transplant from an infected person.


Symptoms typically begin 2 to 4 weeks after you are exposed to the bacteria. Many infected people do not feel sick at all. Fever is the most common symptom. When other symptoms occur, they may include:

  • Sweating.

  • Headache.

  • Back pain.

  • Weakness and fatigue.

  • Chills.

  • Joint pain (arthralgia).

  • Muscle pain (myalgia).

  • Depression.

Your caregiver may also find that your lymph glands, liver, or spleen are enlarged during your exam.


Brucellosis is diagnosed by a lab test that looks for the bacteria in a sample of blood or bone marrow. Blood tests can also look for antibodies that fight the bacteria. Other testing may be done to check for liver damage, since this is a commonly infected organ. Your caregiver may also use imaging tests to check for complications. This may include X-rays, CT scans, or MRI scans.


You will need to take antibiotic medicines for at least 6 weeks. Depending on the severity of your illness, recovery may take a few weeks to several months. If the disease returns, you will need further treatment.


  • Do not consume unpasteurized milk, cheese, ice cream, or other dairy products while traveling. If you are not sure whether a dairy product is pasteurized, do not eat it.

  • Hunters, slaughterhouse workers, and veterinarians should wear rubber gloves when handling sick or dead animals.

  • Immunocompromised people (cancer patients, HIV-infected people, transplant patients) should not handle animals that are possibly infected with a Brucella bacteria.


Take your antibiotics as directed. Finish them even if you start to feel better.


  • Your problems do not go away after 1 or 2 months.

  • Your problems return.

  • You have a fever.

  • You have long-lasting weakness or fatigue.

  • You have aches or pains that do not go away.

  • You cannot take your antibiotics for any reason.


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.