Brucellosis is a bacterial infection that originates in animals, which can cause long-lasting flu-like symptoms. It is rare in most developed countries.
In mainland Britain, brucellosis has 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, it is still a problem globally: brucellosis is the most common zoonotic infection in the world ('zoonosis' means a disease that can be transmitted from animals to humans).
An average of 10 cases of brucellosis are diagnosed each year in England and Wales, usually in people who have acquired it abroad or who have consumed illegally imported cheeses.
What are the high-risk countries?
Brucellosis is a problem in:
- The Middle East
- Central and South-east Asia
- South and Central America
- Southern France
If you are travelling to one of these areas, do not consume unpasteurised milk or milk products.
There is no human vaccine to protect you against brucellosis.
How is it caught?
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 less commonly, by eating the raw meat from these animals
- by inhaling it in dust on farms with infected animals, in abattoirs, or in medical or veterinary laboratories
- via indirect contact with infected animals – for example, a vet may catch it through a needlestick injury or by splashing their eye with a live vaccine
Person-to-person spread is rare, although there have been cases of transmission from mother to baby through breastfeeding, and through sexual contact.
People at higher risk of brucellosis are laboratory workers, veterinarians, farmers and abattoir workers.
What are the symptoms?
Brucellosis doesn't always cause symptoms – the infection may persist for several months without you even knowing.
When it does cause symptoms, they tend to last a long time. Typical symptoms include:
- prolonged fever
- weight loss
- joint pains
In some people, symptoms will develop suddenly over one to two weeks.
In others, symptoms may come on gradually and be persistent or relapsing (returning again and again), lasting for years.
It can occasionally take up to six months for the disease to show.
How is it diagnosed?
Brucellosis is usually diagnosed by your GP taking a blood sample and sending this to a laboratory. The blood sample is tested for the antibodies against the brucellosis bacteria.
What is the treatment?
Brucellosis is treated with two or more different antibiotics, such as doxycycline with gentamicin or doxycycline with rifampicin.
The combination prescribed will vary depending on your age and the severity of the disease.
How serious is it?
Brucellosis can make you feel very ill and be long-lasting, however, it is rarely fatal in humans.
Most people recover completely without complications after antibiotic treatment.
However, if left untreated, up to 2% of patients may develop endocarditis (infection of the heart), which can be fatal.