Nose of dog

One way brucellosis can be transmitted is through inhalation. Photo courtesy of Depositphotos

Brucella canis is getting a lot of attention these days, and taking up more of my time than I ever would have thought a few months ago.

Identification of infected dogs linked to a commercial breeder in Iowa has attracted a lot of attention. It’s hard to say how noteworthy it is, because we know the bacterium is present in some commercial breeding (puppy mill) operations and in imported dogs. It’s of particular concern because it can be transmitted to people, but we don’t know how much of a concern that is or how often it occurs. It seems to be rare, but it can occur (more on that in a minute).

The Iowa situation is still being sorted out, but may pale in comparison to what’s going on in Ontario. We detected Brucella canis in some imported dogs earlier this year, in a group of dogs imported from South Korea (positive dogs from the same region (possibly the same shipment) were later identified in the US as well). That caused a big stink at the time, but settled down.

Of greater concern is the more recent identification of Brucella canis in commercial breeding dogs in Ontario. We have over 100 known or suspected positive dogs (testing is a bit of a pain for this bacterium, to say the least), and since we certainly haven’t tested all (or even most) commercial breeding dogs in the province, it’s reasonable to assume that the true number of affected dogs is much greater.

So, what’s the risk to people?

• We don’t know. It’s a rarely diagnosed disease in humans. The problem is that could be because it’s a rare disease, or because it’s an under-diagnosed disease. It’s probably a combination of both. It seems to be truly rare, but human infections do occur. The greatest concern involves kids, as they’re more susceptible to infection and severe disease, but it can affect others (see below).
  
  
• As we’ve worked through the Ontario situation, my impression has been the overall risk to people is probably still quite low (dogs may be another story). Otherwise, we should have seen a reasonable number of sick people in Ontario. The lingering concern is whether there are infected but as of yet undiagnosed people in the province.

A recent report from of a British Columbia woman who was diagnosed with brucellosis highlights this concern. The woman had non-specific signs including fever, headaches and weight loss for two months before the diagnosis was reached. The link was believed to be a pregnant dog from Mexico (a place from where Brucella-infected dogs have originated before) that spontaneously aborted two stillborn puppies while being transported by the woman in question, who regularly helps move rescue dogs from the US and Mexico. That dog tested positive for Brucella canis and contact with aborted fetuses, fluids and other tissues would be high-risk for transmission of the infection to the person.

One case doesn’t mean it’s a big problem, but it means there’s concern. Here are a few take home messages:

• Brucella canis is of greatest concern in imported dogs and dogs from commercial breeders.
• If you purchased a dog from an internet source, pet store or anywhere else where you don’t have very clear information about the background of the dog, testing for Brucella is a reasonable idea.
• If you are importing dogs or have adopted an imported dog, you should consider testing for Brucella, especially if it came from Asia, Mexico or eastern Europe.
• All breeding dogs should be tested for Brucella at least once a year.
• You shouldn’t freak out about Brucella because human infections seem to be rare, but you should be aware of it.
• Dog owners should make sure their physicians know that they have dogs (as for any pet) and physicians should be aware of the zoonotic potential of Brucella canis.

For more information, check out the OAHN factsheet on Brucella canis for veterinarians and our archives.

Reprinted with permission from Worms and Germs 

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