Brucellosis in Dogs: A Vet’s Guide to Symptoms and Treatment

Although there have never been cases of brucellosis in dogs in the UK, cases have been on the rise over the past couple of years.

These cases are usually linked to dogs imported from Europe, although transmission within the UK (opens in a new tab) also happened now.

If you own a foreign shelter, work with dogs, or even spend a lot of time with dogs, you should read on for the latest news on canine brucellosis.

What is brucellosis in dogs?

Brucellosis in dogs is a reproductive disease caused by bacteria Brucella canis. Unless dogs are breeding, it is not always obvious that they are infected, as the disease is accompanied by few symptoms.

However, it is still an important disease to be aware of because brucellosis can be transmitted to humans. Once a dog has brucellosis, they should be considered infected for life and will always be a risk to others.

How do dogs get brucellosis?

The bacterium responsible for brucellosis is carried in the bodily fluids of infected dogs. While the main way dogs catch brucellosis is through mating, it can also be carried in saliva, blood, feces and secretions from the eyes and nose, and dogs who ingest or even inhale the bacteria can be infected.

Additionally, mothers can pass it to their puppies in milk or in their womb, although most female dogs with brucellosis abort their litters.

Although brief contact with an infected dog is unlikely to cause a dog to become infected, prolonged contact (such as sharing a house) can cause infection, as can spending time in an environment where an infectious dog has been.

How is brucellosis contagious?

Brucellosis is quite contagious between dogs – although rare, it is possible for dogs to catch brucellosis simply by sniffing the areas where an infected dog has passed urine or feces.

In most cases, neutered dogs without symptoms will be much less likely to transmit brucellosis to other dogs, while the highest risk comes from pregnant female dogs.

These dogs usually abort their litter, and abortive fluids are highly contagious as they contain a lot of bacteria. Fortunately, although brucellosis can infect humans, it is much more difficult for a human to catch it than a dog – the main risk is for people who work closely with whole dogs, such as breeders and veterinarians.

pregnant female dog lying on the floor

(Image credit: Getty Images)

Can brucellosis affect male and female dogs?

Yes, brucellosis affects both male and female dogs. It is spread by mating and the bacterium is often found in seminal fluid in men or in vaginal secretions in women.

What does brucellosis look like in dogs?

One of the problems with this disease is that many dogs do not show the symptoms of brucellosis. The most common symptoms are related to breeding – infertility, aborted litters or weak puppies. Since most people do not actively breed their dogs, they may not see any signs of brucellosis in their dog at all.

Other symptoms of brucellosis in dogs include:

  • Lethargy
  • Decreased activity
  • Lameness
  • Back ache
  • Weightloss
  • Eye problems
  • Swollen testicles
  • Swollen lymph nodes

However, it is important to know that many dogs do not show symptoms but are still able to transmit the disease to other dogs or humans.

How long does it take for brucellosis symptoms to appear?

Once infected with brucellosis, a dog may show mild signs, but may also remain asymptomatic. This means you can’t assume your dog is negative just because you haven’t seen any symptoms.

If your dog has been imported or has been in contact with an imported dog for extended periods of time, it is best to have them tested, especially if your dog is not spayed (neutered).

How to Test for Brucellosis in Dogs

So how do we go about testing for brucellosis? There are several tests available, none of which are perfect. The most accurate test involves your veterinarian sending a sample to an outside lab.

This will provide a quick response if your dog has brucellosis. An in-clinic option (much like home covid testing) is available but will not be stocked by all veterinary practices.

False positives are also possible with this test – all positives must be confirmed by sending a sample to the external laboratory. These tests may need to be repeated a few months later if your dog’s exposure to brucellosis is recent, as the levels may still be undetectable.

If a dog is confirmed positive for brucellosis in the UK, the the result must be reported to the APHA (opens in a new tab)the government body responsible for animal health in the UK.

veterinary examination dog

(Image credit: Getty Images)

Treating Brucellosis in Dogs

Unfortunately, once a dog is infected with brucellosis, it is considered infected for life. Treatment with antibiotics can reduce symptoms and dogs seem to recover from brucellosis, but the dog will still be able to spread the disease.

Spaying dogs can also reduce the risk of spreading the disease, but does not eliminate it entirely. Infected dogs will not be allowed to come into contact with other dogs and should not be taken to areas frequently visited by other dogs, which severely limits their quality of life.

Should dogs with brucellosis be euthanized?

Although this seems extreme, especially when many dogs show no symptoms, the recommended course of action when a dog is diagnosed with brucellosis is euthanasia.

Indeed, no treatment can prevent the dog from being a danger to others, as well as to humans. For safety reasons, limitations must then be imposed on the dog – you will be asked to keep them away from other dogs, not to walk them in areas frequented by other dogs and not to allow them to greet people.

Veterinarians may not be able to hospitalize your dog or operate on it due to the risk to their staff and other patients. They are unlikely to be accepted by groomers or boarding houses, and you will need to maintain excellent hygiene in the home, wash your hands after touching your dog, and not allow him to spend time in the main rooms of your dog. the House.

For all of these reasons, it is generally considered milder to euthanize a dog when it has been confirmed to be infected with brucellosis.

Dr. Joanna Woodnutt MRCVS

After graduating as a veterinarian from the University of Nottingham, Dr Joanna Woodnutt (opens in a new tab)then practiced companion animal medicine in the Midlands. She quickly developed a love for consulting and helping clients with medical issues such as dermatology, behavior and nutrition, and wrote for countless online and print publications.

What about humans? How dangerous is brucellosis for me?

Brucella canis can spread to people, especially where the number of shed bacteria is high. The greatest risk is for those who assist dogs with whelping or who handle a lot of bodily fluids, such as veterinarians and breeders.

However, anyone can catch brucellosis from a dog if they have sustained contact, especially if they are immunocompromised in any way. The symptoms (opens in a new tab) include weight loss, headache, fever, sweating and back pain, and treatment is essential to prevent more serious problems.


Brucellosis is fortunately still rare, but it is on the increase. Where previously it was entirely restricted to dogs from overseas, it is now moving from dog to dog in the UK.

If your dog has been rescued from abroad or has been in constant contact with a dog from abroad, it is a good idea to have him tested, especially if you have noticed symptoms.

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