Brucellosis in Dogs


  • Canine brucellosis is an infectious disease in dogs, caused by a bacteria called ‘Brucella canis’.
  • In dogs, it mainly affects the reproductive organs (womb and testicles), causing infertility and pregnancy loss, but can also travel to the joints and spine, causing lameness and back pain.
  • Brucella canis is common in other countries around the world but historically the UK has been considered free of it.
  • Vets are seeing an increase in cases due to the rise in dogs being imported into the UK.
  • Canine brucellosis is zoonotic, meaning it can also cause illness in humans who have been in contact with infected dogs but fortunately, this is very rare.
  • It’s important that we control the spread of canine brucellosis to protect both human and animal health.

What is Canine brucellosis?

A brown and white dog looking alert while lying on dusty concrete.

Canine brucellosis is an infectious disease that affects dogs and is caused by a bacteria called Brucella canis. It mainly affects the reproductive organs (womb and testicles) causing infertility and pregnancy loss, but it can also cause lameness, back pain, lethargy and swollen lymph nodes. Some infected dogs show no symptoms, which means they can silently carry Brucella canis without us knowing.

Brucella canis can cause illness in people who have been in contact with infected dogs but, fortunately, this is very rare. We strongly recommend that any dog coming to the UK from a country with Brucella canis is screened for it before they travel. If you are considering importing a dog, speak to your vet for advice about testing, and make sure the dog has tested negative before they enter the UK. Your vet may also advise repeat testing a few months after your dog arrives in the country.

How do dogs catch brucellosis?

Brucella canis travels in reproductive/birthing fluids and tissue, semen (sperm), vaginal discharge (including blood during a season), and milk. It also travels in urine, blood, poo, saliva and snot, however, these fluids seem to be less infectious.

The most common way for a dog to catch brucellosis is by:

  • Mating with an infected dog.
  • Licking/eating/sniffing infected birthing fluids from an infected dog – once an infected dog has given birth or miscarried, she will continue to shed large amounts of Brucella canis bacteria in her vaginal fluids/discharge for 4-6 weeks.
  • Sniffing or licking the genitals of an infected dog, especially female dogs in season.
  • Puppies can catch it in the womb or through contaminated milk if their mother is infected.

Less common (but still possible) ways for a dog to catch brucellosis is by:

  • Coming into contact with infected urine or blood.
  • Contact with saliva, poo or snot.
  • From an environment that has had infectious material such as birthing fluids or tissue in it. An environment can stay contaminated for several months.

How common is brucellosis?

Before 2020, the UK had very few diagnosed cases of Brucella canis. Although case numbers are still low in the UK, since 2020 there has been a significant increase in diagnosed cases due to the rise in dogs being imported and an increase in testing for Brucella canis. Brucella canis is common in Eastern Europe, South America, parts of North America, the Middle East and Asia.

Brucellosis symptoms in dogs

Some dogs with Brucella canis have no symptoms, while others do. Either way, they can still be infectious to other dogs and people. Possible symptoms include:

  • Pregnancy loss (usually between day 45-59 of pregnancy)
  • Stillbirth
  • Infertility in male and female dogs (not able to get pregnant)
  • Weak puppies that die soon after birth
  • Swollen testicles (males)
  • Irritation of the skin around the testicles (males)
  • Lameness and back pain
  • Swollen lymph nodes
  • Low energy (lethargy)


Your vet will ask if your dog has any symptoms, if it has been imported or has been in contact with an imported dog, or if it has recently travelled overseas. They may advise doing a blood test to check for Brucellosis and they may want to run more than one blood test.

After a dog is exposed to brucellosis, it can take up to three months for it to show up in a blood sample. So if it’s been less than that since your dog has come into the UK or been in contact with an infected dog, they will need to be retested after three months.

If your dog is diagnosed with brucellosis, it must be reported to ‘The Animal and Plant Health Agency (APHA)’ by law. The local health protection team will then get in touch to give you further advice.

Can Brucella canis spread from dogs to humans?

Brucella canis is a zoonotic disease which means it can spread from animals to humans, however this is rare. While owners of imported dogs may be at more risk of getting Brucella canis than the general population, the overall risk of getting infected with Brucella canis is fortunately very low.

The most common way for humans to catch brucellosis is if they come into contact with the birthing fluid or tissue from an infected dog. This includes their vaginal discharge, which is extremely infectious for four to six weeks after giving birth or miscarrying. People in regular contact with imported dogs, vets and vet nurses, and lab staff who handle bodily fluids are at the highest risk of being exposed. Although the risk to the general public is extremely low, it’s important to practice good hand hygiene (see risk management below) and avoid touching birthing/reproductive products, blood or urine (pee) from all imported dogs. Even dogs without any symptoms can spread Brucella canis.

People with a weak immune system are likely to be at higher risk of severe infection, so if you, or a member of your household, is pregnant, immunosuppressed, or a young child, you (or they) should consider limiting your interactions with an infected dog.

Treatment and management of infected dogs

Unfortunately, there is no treatment that guarantees a cure for brucellosis in dogs, whether they have symptoms or not. If your dog tests positive for Brucella canis, your vet will discuss the different options available for your dog. Your choice will likely depend on several factors including whether your dog has any symptoms, what their quality of life is like and whether you have anyone with a weak immune system living in your house.

  1. Putting them to sleep: if your dog is suffering from symptoms caused by brucellosis, it can be extremely difficult to treat them successfully and putting them to sleep may sometimes be the only way to stop their suffering. If your dog is infected, the only way to completely prevent any future risk of passing the disease on to other dogs or humans is euthanasia. However, this is a difficult decision to make if your dog is otherwise well, and you may choose to manage the infection and its long-term risks.
  2. Neutering your dog will reduce the chances of them passing the infection on to other dogs and humans. However, it’s important to remember that it does not completely stop them from passing it on. Your vet may recommend a short course of antibiotics before neutering, as it may help protect the veterinary team who are treating your dog from becoming infected. There may also be a chance of an infection flare-up after neutering and antibiotics can lessen the chance of this happening.
  3. Antibiotics: unfortunately, many dogs remain infected with Brucella canis even after treatment with antibiotics, as a result, long courses of antibiotics are not recommended to treat Brucella canis. The bacteria can hide in parts of the body that are hard for antibiotics to reach. Using long courses of antibiotics may also cause antibiotic resistance which can make it more difficult to treat infections later on.
  4. Long-term risk management: to reduce the chance of Brucella canis spreading it is important to follow these guidelines:
    • Remember to wash your hands after every interaction with your dog. Use soap and hot water for at least 20 seconds. If your hands aren’t visibly dirty and there are no hand washing facilities available, you can use alcohol hand sanitiser instead.
    • For added protection, you may want to use surgical gloves, eye protection, and/or a face mask when interacting with your dog, especially if they are giving birth or weaning.
    • Avoid any contact with any discharge from their vagina/penis.
    • Never breed them and have them neutered at a clinic that can do it safely. It’s important to let your vet practice know if your dog has tested positive for Brucella canis so they can put precautions in place to protect the veterinary team.
    • If you, or a member of your household, is pregnant, has a weak immune system, or is a young child, you (or they) may wish to consider limiting interactions with the infected dog as there is a higher risk of developing severe disease if you (or they) become infected.
    • Hard surfaces where there has been birthing tissue/fluids or urine should be thoroughly disinfected with a strong bleach solution. Soft furnishings should be disposed of or steam cleaned.

None of these measures will cure your dog of brucellosis, and it’s important to know there will always be some degree of infection risk to you and any other dogs or people they come into contact with.

When to contact your vet

It’s important to contact your vet for advice if:

  • You are considering buying or rehoming an imported dog.
  • You own an imported dog who has never been tested for brucellosis.
  • Your dog has been in contact with a dog with brucellosis.
  • Your dog is showing symptoms of brucellosis, especially if they’re imported or have travelled outside of the UK.

Due to limited charitable resources, PDSA is unable to offer brucellosis screening unless your dog is unwell and highly suspected to have the disease. We recommend contacting a private veterinary practice for routine screening of at-risk dogs.

You know your dog best, always contact your vet if you’re concerned.


Treatment for Brucella canis can become expensive, so it’s important to speak openly with your vet about the cost of treatment, your finances, and what you think is right for your dog.

Consider taking out dog insurance as soon as you bring your dog home, before any signs of illness start. This will give you peace of mind that you have some financial support if they ever become unwell.


Is there a vaccine for brucellosis in dogs?

Unfortunately, there isn’t yet a vaccine for brucellosis in dogs.

Should all imported dogs be screened for brucellosis before entering the UK?

Yes, we strongly recommend that any dog entering the UK from another country is screened for brucellosis before they travel. If you are considering importing a dog from abroad, speak to your vet for advice about testing, and make sure the dog is confirmed negative before they enter the UK. Unfortunately, PDSA is unable to offer brucellosis screening as part of its charitable service.

Is my dog at risk of catching Brucella from other dogs in the UK now?

Despite rising cases, the risk that your dog will catch brucellosis in the UK is still very low, especially if they don’t spend time with untested imported dogs. If you already have a dog and are considering importing another from abroad, make sure they are confirmed negative for brucellosis before they enter the UK.

What are the symptoms of Brucella canis in humans?

Brucellosis usually causes symptoms in humans such as a high temperature, loss of appetite, weight loss, sweating, headaches, tiredness (fatigue), and back and joint pain. Illness can be much more serious in young children, pregnant women and people with weak immune systems. Symptoms tend to take between a few weeks to several years to develop. Fortunately, brucellosis in humans is very rare and unlike in dogs, it is treatable. If you are concerned that you have been exposed to brucellosis, contact your doctor for advice.

Published: March 2024


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Written by vets and vet nurses. This advice is for UK pets only. Illustrations by Samantha Elmhurst.