Brucellosis

What is it?

Brucellosis is a bacterial infectious disease that affects cattle, goats, sheep and camels, and which can also be transmitted to humans. It mainly causes abortions and reproductive problems in affected animals. This disease is a significant public health concern in Tunisia due to its possible transmission via unpasteurized dairy products.

🎬 Watch the video

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Causes and risk factors

Brucellosis is caused by bacteria of the Brucella genus, notably Brucella abortus in cattle and Brucella melitensis in goats and sheep. These bacteria settle in the reproductive tract and mammary glands of infected animals.

The introduction of new, untested animals into a herd, lack of vaccination and close contact between herds increase the risk of spread. Traditional breeding conditions with mixing of herds also constitute a risk factor in Tunisia.

Transmission

The disease is transmitted primarily through contact with abortion products, placenta, or vaginal discharge from infected animals. It can also be spread by ingesting contaminated, unpasteurized milk. Transmission to humans often occurs through direct contact with infected tissues or through consumption of raw dairy products.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

Treatment

Treatment of infected animals is generally not recommended. The bacteria hide inside the animal's cells. Antibiotics therefore rarely eliminate the infection reliably, and the animal can remain a carrier and contagious.

The course of action is decided by the veterinarian, in liaison with the veterinary authorities. It most often relies on confirmation by laboratory tests, isolation of suspect animals and screening of the herd. Animals confirmed as infected are generally removed from the herd, in accordance with current regulations.

The veterinarian also explains the hygiene measures: safe disposal of placentas and aborted foetuses, cleaning and disinfection of premises, and protection of people who handle the animals. Never attempt to treat a suspect animal yourself.

Prevention

Vaccination

Live attenuated vaccines exist against Brucellosis in ruminants. Generally, a strain called S19 or RB51 is used in cattle, and a strain called Rev-1 in goats and sheep.

Vaccination is usually carried out in young females, before their first pregnancy. The choice of vaccine, age and schedule falls under official programmes and the veterinarian's advice. These vaccines can be dangerous for humans in case of accidental needlestick or splashing. They must therefore be handled only by a professional. They may also cause abortions in a pregnant female.

Vaccination does not replace screening or hygiene measures. There is no vaccine for humans.

Possible complications

In females, the disease can cause repeated abortions, reduced fertility, uterine infection and a drop in milk production.

In males, it can cause inflammation of the testicles and infertility.

Swollen or painful joints may also appear in some animals.

Carrier animals showing no visible signs can contaminate the herd and people for a long time.

In humans, the disease can become chronic, with recurring fever and joint pain. It can also affect other organs.

For the farmer, the consequences are economic: losses of young animals, reduced production and restrictions on the animals or their products.

When to see a veterinarian

References

WOAH — Organisation mondiale de la santé animale (ex-OIE)

OMS — Organisation mondiale de la santé

Content reviewed by the TunisieVet editorial team · Updated 02 November 2026