Brucellosis: Understanding, Symptoms, Causes & Treatment

Brucellosis: Understanding, Symptoms, Causes & Treatment

Brucellosis is a disease you get from the bacteria Brucella. You get brucellosis from drinking unpasteurized milk, eating unpasteurized milk products or handling infected animals. Symptoms can come and go for a long time and include fever, joint pain and sweating. Brucellosis is treated with antibiotics.

What is brucellosis?

Brucellosis (pronounced “bru-cell-OH-sis”) is a disease you get from the bacteria Brucella. It can cause vague symptoms like fever, joint pain and sweating that come and go over a long time.

Brucellosis is a zoonotic disease, meaning you get it from animals. It’s also sometimes called undulant fever, Malta fever, Mediterranean fever and many other names.

Who does brucellosis affect?

Brucellosis exists in most countries of the world. You’re at higher risk for a Brucella infection if you:

  • Are a veterinarian or work with animals.
  • Work on a dairy farm or ranch.
  • Are a butcher, work in a slaughterhouse or handle raw meat.
  • Hunt animals or field dress.
  • Work in a lab that handles Brucella.
  • Eat uncooked meat or unpasteurized milk products.

How common is brucellosis?

There are about 500,000 cases of brucellosis worldwide each year. Brucellosis is rare in the U.S., with only 100 to 200 cases each year.

What does brucellosis do to humans?

Brucella, the bacteria that causes brucellosis, gets into your body through your mouth, nose, eyes or a break in your skin. From there, it gets into your lymph nodes or tissues where it slowly multiplies. From there, it can infect almost any part of your body, including your heart, liver, brain and bones, and cause swelling and damage.

Symptoms and Causes

What are the symptoms of brucellosis?

Symptoms of brucellosis take two to four weeks or longer to appear after you’re exposed to the bacteria. Symptoms can come and go for months or years, including:

  • Fever.
  • Sweating (sometimes with a moldy smell).
  • Joint pain, especially in your hips, knees or lower back.
  • Unexplained weight loss.
  • Headache.
  • Abdominal (stomach) pain.
  • Loss of appetite or upset stomach.
  • Depression.
  • Large, painful lymph nodes.
  • Generally feeling unwell.

What causes brucellosis?

Several types of Brucella bacteria cause brucellosis, including B. abortus, B. canis, B. meliensis and B. suis. Animals carry Brucella, including:

  • Cattle.
  • Goats.
  • Pigs.
  • Deer.
  • Moose.
  • Elk.
  • Sheep.
  • Dogs.
  • Camels.

How is brucellosis transmitted?

Brucellosis is transmitted through contact with infected animals or unpasteurized dairy products. You can get brucellosis by:

  • Drinking unpasteurized (raw) milk or eating unpasteurized cheese, ice cream or other milk products. Infected animals produce contaminated milk. However, pasteurization kills the bacteria so you can safely drink milk from sheep, goats, cows or camels even if they have brucellosis.
  • Touching the infected tissue or body fluids of an animal. Brucella can get into your body through breaks in your skin or through your eyes, nose or mouth.
  • Inhaling Brucella. You can breathe particles of Brucella in from the air, usually from the exposed tissues or blood of an infected animal. This is a risk if you work with Brucella in a lab, dress game or work on a farm, in a slaughterhouse or in a meat packing plant.
  • Eating undercooked meat.

While person-to-person transmission is a very unlikely way to get brucellosis, there have been rare cases of Brucella transmission:

  • From a person who is pregnant to their unborn child.
  • Through breastfeeding/chestfeeding.
  • Through sex.

Is brucellosis a STI?

No, brucellosis isn’t considered a sexually transmitted infection (STI). There have only been rare cases of brucellosis spreading through sexual contact.

Diagnosis and Tests

How is brucellosis diagnosed?

A healthcare provider diagnoses brucellosis by asking about your symptoms and testing your blood, tissues or other samples for signs of the bacteria Brucella. As symptoms of brucellosis can look like other diseases, your provider may test you for other conditions to rule them out.

The best way to confirm a Brucella infection is through growing the bacteria from body fluid or tissue. Brucella is slow-growing, so it may take a few weeks to confirm your diagnosis. You may need to do more than one blood test over a few weeks to check for signs of Brucella.

What tests will be done to diagnose brucellosis?

Your provider might get body fluid samples, and use imaging or other tests to help diagnose brucellosis, including:

  • Blood tests. Your provider will take a sample of your blood from your arm using a needle. A lab can look for signs of Brucella (antibodies, antigens or DNA) in your blood or try to grow it over time (culture).
  • Tests of other body fluids. Your provider may take samples of fluid from your spinal canal, joints or other parts of your body to look for signs of Brucella or grow it over time.
  • Tissue biopsy. Your provider may take samples of your bone marrow or other tissue to look for signs of Brucella or grow it over time.
  • Imaging. Depending on which parts of your body are affected, your provider may order X-rays, CT scans, MRI, bone scans, ultrasounds or an echocardiogram. These take pictures of the inside of your body to see if there are any changes to your bones or organs.

Management and Treatment

How is brucellosis treated?

Your healthcare provider will treat brucellosis with a combination of at least two types of antibiotics. You’ll need to take them for at least six to eight weeks. Depending on your specific case, you may need other therapies (like draining infected areas or managing complications).

What medications are used to treat brucellosis?

Antibiotics healthcare providers prescribe to treat brucellosis include:

  • Streptomycin or gentamicin.
  • Rifampin.
  • Doxycycline.
  • Trimethoprim/sulfamethoxazole (TMP/SMX).
  • Ciprofloxacin.

How do I manage the symptoms of brucellosis?

In addition to taking prescribed antibiotics to get rid of the bacteria, you may be able to manage some symptoms of brucellosis, like joint pain and fever, at home. Ask your healthcare provider if there are over-the-counter (OTC) medications or other therapies that are safe for treating your symptoms.


How can I reduce my risk of brucellosis?

You can reduce your risk of brucellosis by practicing safe food handling and wearing protective clothing while working with animals, for instance:

  • Don’t drink unpasteurized milk or eat foods made with unpasteurized milk.
  • Wear appropriate safety gear when working with animals and animal tissues. This might include gloves, an apron or goggles. Butchers, veterinarians, hunters, farmers and people who work in slaughterhouses or medical labs need to be especially careful.
  • Cook meat to safe temperatures and always wash your hands and the surfaces and utensils you used to prepare your food. Game meat can be infected with Brucella.

Outlook / Prognosis

What can I expect if I have brucellosis?

Most people with brucellosis will make a full recovery with antibiotic treatment, but it can take a long time. You can expect to take antibiotics for several weeks or months to make sure all the bacteria in your body are gone.

Sometimes, brucellosis can come back after you’ve finished treatment, especially if you don’t take antibiotics long enough. Some symptoms, like arthritis, can last a long time, even after you finish treatment. You may need additional medications or therapies if you have complications of brucellosis.

Complications of brucellosis

Complications of brucellosis are more likely if it goes untreated for a long time. Complications include:

  • Ongoing arthritis.
  • Enlarged liver (hepatomegaly) or spleen (splenomegaly).
  • Chronic hepatosplenic suppurative brucellosis (CHSB). CHSB is an infection that causes abscesses (pockets of pus) in your spleen and liver. It can happen years after a Brucella infection.
  • Infection and inflammation of your heart (endocarditis), brain or its covering (encephalitis or meningitis), spine (spondylitis), bones (osteomyelitis) or lower back (sacroiliitis).
  • Swelling of your epididymis (tube that carries sperm) and testis (epididymo-orchitis).
  • Miscarriage.

Can Brucella in humans be cured?

Yes, Brucella infections in humans can be cured by antibiotics. However, some complications can cause lasting damage.

Can brucellosis cause death?

It’s rare for someone to die of brucellosis. The fatality (death) rate from brucellosis is between 1% and 2% of all cases.

Living With

How do I take care of myself with brucellosis?

If you’ve been diagnosed with brucellosis, take all of your medication as prescribed by your provider, even if you feel better. If you stop taking antibiotics too soon, brucellosis can come back. Contact your provider if you have new or worsening symptoms.

When should I see my healthcare provider?

See a healthcare provider if you have symptoms of brucellosis, especially if your work or hobbies put you at risk for infection.

When should I go to the ER?

Go to the ER if you have symptoms of serious illness, including:

  • High fever (over 103 degrees Fahrenheit/39.4 degrees Celsius).
  • Severe abdominal (stomach) pain.
  • Confusion or other mental changes.

What questions should I ask my provider?

  • How long does treatment last?
  • How do I take my medications?
  • How can I manage my symptoms at home?
  • When should I follow up with you?
  • What symptoms should I go to the ER for?


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