You may have heard recently that owners of imported dogs are increasingly being asked to get blood tests done for a relatively rare infection, Brucella canis. In some cases, vet practices are reportedly saying that they will not provide treatment for dogs who test positive. So what’s going on, and why are we suddenly testing all these dogs?

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Dogs and Brucellosis

The family of bacteria that cause brucellosis are notorious pathogens. It causes severe effects on the reproductive tract as well as longer-term health problems in a range of species, often including humans. Globally, brucellosis in humans has a significant impact on human health, animal health, and economics; but gets very little attention from public health bodies. The specific species in dogs, Brucella canis, is less aggressive to humans than some other strains. But it still poses a risk to human health.

Brucellosis symptoms in dogs

Many affected dogs will have subclinical disease, which is not immediately apparent. However, full-blown clinical disease can take months or years after infection to develop.

In most cases, the infection causes reproductive symptoms:

  • Abortion, still-births or weak puppies in pregnant dogs
  • Reduced fertility in both males and females
  • Orchitis (testicular inflammation) and testicular atrophy (shrinkage) are common in males

However, affected dogs are also at risk of infection of other organs; especially the bones and joints of the spine (discospondylitis), the eye (uveitis and chorioretinitis), and the meninges around the brain (meningitis). This can result in pain when walking, stiffness, loss of balance, lethargy, altered or loss of vision, eye pain, seizures and even death.

Unfortunately, there is no known way to remove 100% of the bacteria. Antibiotics followed by neutering significantly reduce the risk of further disease and spread (as the ovaries and testicles are the main site where the bacteria hide). But they do not eliminate the risk to that dog, other dogs, or people.

Brucellosis symptoms in people

Humans, fortunately, are relatively resistant to canine brucellosis, and death from the infection is very, very rare. However, this does not mean that it is safe or that there is no risk. 

Most healthy non-pregnant adults who are infected will develop moderate flu-like illness, with a prolonged fever and enlargement of lymph nodes and spleen. Most will make a full recovery.

However, more serious complications are well recognised; including infections of the heart (endocarditis), joints (septic arthritis), bones (osteomyelitis) and spine or brain (epidural abscessation). There are also reports of respiratory disease (pneumonitis or interstitial pneumonia) and long-lasting nerve damage after infection (Guillain Barré syndrome).

In children and the immunocompromised, severe disease is much more likely. It is highly likely that Brucella canis can also cause miscarriages and stillbirths if someone is infected while pregnant.

How much of a risk is it really?

This really is the problem: cases appear to be rising. This is almost certainly due to rising numbers of untested imported dogs. In 2020 (the last year we have full records for), about 66,000 dogs were legitimately imported into the UK. However, the number of actual imports using technically illegal schemes was probably much, much higher, with some research suggesting as many as 300,000 dogs being imported through the “back door” of the pet travel schemes.

Sadly, very few of these dogs will have been tested for brucellosis, because our current import policy does not require it.

However, recent research suggests that between 1.6% and 1.7% of dogs imported into the UK may be carriers or are actively infected. This doesn’t sound much. But even if we ignore the pet import loophole, that means between 1000 and 1500 infected dogs are brought into the UK every year. In reality, the numbers are likely to be much, much higher.

Vets are quite right to want to know which animals are infected, so that suitable protective measures can be put in place, to minimise the risk to their owners, and also to other dogs in the country. 

Should I get my dog tested?

If your dog was imported from a country where brucellosis is more common than the UK (so most of Southern, Eastern and Central Europe, Asia, Africa or the Americas), then yes you should. 

As far as we know, the disease is still rare in the UK. And we really want to keep it that way! If positive, this will certainly mean that your dog needs neutering and isolating from others. The best way to eliminate the risk is euthanasia, but of course this is case dependent; if your dog is happy living an indoors life and no-one in the family is very vulnerable, you might want to accept the risk and keep them with you, which is fine, as long as your vets (and any other caregivers or visitors) know that they need to take additional precautions when dealing with them.

However, bear in mind that some tests are more accurate than others. Take a look at this article for more details before making a firm decision on what to do.

Can it be prevented?

This whole sorry sage could have been prevented if we had a proper programme for testing imported dogs for exotic pathogens such as Brucella canis, Leishmania, and others, as we have been arguing for years. It’s still not too late, so if you are planning to import a dog, please, please, PLEASE make sure they are fully tested so you know what you’re getting into!

Want to know more detail?

There’s a recent article from Veterinary Voices UK that discusses this, and more, in a lot more detail – I strongly advise that if you’re interested in brucellosis you check it out!