Brucellosis is a bacterial infection originating in animals that can cause long-lasting flu-like symptoms. It's rare in most developed countries.
In mainland Britain, brucellosis has effectively been wiped out from cattle, goats, sheep and pigs through the vaccination of animals, the test and slaughter of infected herds and the pasteurisation of milk.
However, brucellosis is still a problem globally – it's the most common bacterial infection spread from animals to humans worldwide.
It's a particular problem in parts of:
The Middle East
South and Central America
countries by the Mediterranean Sea – such as Greece, Turkey, Portugal, Spain, Italy and Southern France
An average of 10 cases of brucellosis are diagnosed each year in England and Wales, and these are almost always in people who have acquired it abroad.
How the infection is spread
Humans usually become infected with brucellosis in one of the following ways:
by consuming unpasteurised milk or milk products (such as soft cheeses) from infected animals, or very rarely, by eating raw meat from these animals
by inhaling it in dust on farms with infected animals, in abattoirs, or in medical or veterinary laboratories
through direct contact with infected animals or surfaces – for example, a farmworker may become infected if the bacteria get into broken skin or their eyes
Person-to-person spread is very rare, although there have been cases of transmission from mother to baby through breastfeeding, and through sexual contact.
People at highest risk of brucellosis are laboratory workers, veterinarians, farmers and abattoir workers.
Signs and symptoms
Brucellosis doesn't always cause symptoms, and the infection may persist for several months without you knowing.
In some people, symptoms will develop suddenly over one to two weeks. In others, symptoms may develop gradually and be persistent or return again and again, lasting for years.
Typical symptoms include:
a high temperature (fever)
loss of appetite and weight loss
fatigue (extreme tiredness)
back and joint pain
These symptoms tend to last a long time and can make you feel very ill, but most people will eventually make a full recovery after treatment.
Brucellosis is rarely fatal in humans, although some cases can lead to life-threatening complications such as endocarditis (infection of the heart) and meningitis (infection of the membranes surrounding the brain and spinal cord) – particularly if left untreated.
Diagnosis and treatment
Brucellosis is usually diagnosed by taking a blood sample and sending this to a laboratory. The blood sample is tested for the antibodies against the brucellosis bacteria.
The infection is treated with a combination of two or more different antibiotics, such as doxycycline with gentamicin or doxycycline with rifampicin.
These will usually need to be taken for at least six weeks.
There is no human vaccine to protect you against brucellosis, so it's important to take precautions to prevent infection if you're at risk.
If you're travelling to an area where brucellosis is a problem, don't consume unpasteurised milk or milk products, and only eat meat that has been thoroughly cooked.
Cheese and other milk products imported illegally from countries where brucellosis is common may not have been pasteurised. Cases have occurred in the UK as a result of eating such products.
If you work closely with animals that could be infected, make sure you wear adequate protective clothing. This might include gloves, an apron, goggles, and a mask that covers your nose and mouth.
Make sure that any wounds you have are cleaned and covered with a suitable dressing or bandage before dealing with animals, and make sure to clean your skin thoroughly afterwards with water, soap and a disinfectant.