What types of Brucella can make people ill?

There are four types of Brucella that can cause illness in humans.

•    Brucella abortus: found in goats, sheep and cows
•    Brucella melitensis: found in sheep and goats
•    Brucella suis: mainly found in pigs (including wild boar)
•    Brucella canis: found in dogs

People can become infected through contact with these animals. Read more below: ‘How does brucellosis spread?’

What are the symptoms of brucellosis?

Brucellosis often starts suddenly with mild symptoms that slowly grow worse. The first symptoms often are:

• mild fever, which sometimes goes away and then comes back
• headache
• tiredness
• listlessness (do not feel like doing anything)
• sweating
• joint pain

If the illness becomes more serious, people may also develop inflammation in different parts of the body. This could affect:

• joints
• testicles
• bladder
• kidneys
• lungs
• heart valves
• brain and spinal cord membranes (meningitis)

These inflammations are more common in infections involving Brucella abortus and Brucella melitensis. Brucella canis usually causes more mild symptoms.

If brucellosis is not detected and treated in time, the patient could end up with permanent damage.

Who has a higher risk of brucellosis?

Some people have a higher risk of getting a Brucella infection, and are therefore at higher risk of developing brucellosis. This mainly applies to:

• people who were recently in countries where Brucella is common and, during their time there:
  • drank or ate raw milk or dairy products
  • had direct, unprotected contact with amniotic fluid, placenta or other tissue from animals
• people working in a laboratory who work with the Brucella bacteria
• people who are in frequent contact with birth material, tissues or bodily fluids from animals. This includes veterinarians, animal breeders and slaughterhouse workers.

Almost no information is available about which people might have a higher risk of becoming seriously ill from brucellosis.

Is it dangerous to get brucellosis during pregnancy?

There is no evidence that brucellosis causes more serious illness during pregnancy. However, there are risks to unborn children. A person who gets brucellosis during pregnancy has a higher risk of miscarriage or preterm birth. The risk is highest until the sixth month of pregnancy.

How does brucellosis spread?

People can get brucellosis if they are exposed to Brucella and develop an infection. The Brucella bacteria can be found in milk and meat from goats, sheep, cows and pigs. People can become ill from undercooked dairy and meat products.

Brucella can also be found in birth material (such as amniotic fluid, placenta or foetus tissue) or bodily fluids (such as urine or saliva) from animals. Direct contact can make people ill.

The time between exposure and illness (the incubation period) is 5 days up to several months, depending on the type of bacteria. The incubation period is usually 2 to 4 weeks.

How can I prevent brucellosis?

There are a number of things you can do to prevent brucellosis:

• always heat meat and dairy products before eating or drinking them
• do not go near animal births
• do not touch any birth material or bodily fluids from animals
• if you touch an animal, wash your hands thoroughly

If you were in contact with an infected animal, and develop symptoms that look like brucellosis, contact your GP.

Is there any treatment for brucellosis?

Brucellosis in humans can be treated effectively with antibiotics. Treatment takes at least 6 weeks. In some cases, symptoms may return after treatment.

How common is brucellosis in the Netherlands? 

Brucellosis is very rare in the Netherlands. The Municipal Public Health Service (GGD) and RIVM receive four or five reports a year of people who have brucellosis. These people contracted the infection in a different country.

Brucella suis has not been found in the Netherlands since 1973, and Brucella abortus has been eradicated since 1997. Brucella canis was not found in the Netherlands until 2016, but has been seen a number of times since then in dogs brought to the Netherlands from Eastern Europe. In 2021, there was one confirmed case of brucellosis in a human that was caused by Brucella canis.