At the 2018 American College of Veterinary Internal Medicine (ACVIM) forum, Dr. Michelle Evason gave an update on the Canadian canine lifetime Lyme study, which she also wrote about briefly last year on this blog when the study was launched. It’s a longterm (lifetime, hopefully) study following a large group of dogs, looking at Lyme disease, tick exposure, owner education and various other things (e.g. diet, lifestyle). Longterm studies that follow the same animals are rare because they’re a lot of work and don’t fit into the typical “get a grant, get a student, get it done” approach to research, but they’re critical to fill in important knowledge gaps.
Here are some highlights from the year 1 update:
174 puppies have been enrolled so far.
All 174 were negative for Borrelia burgdorferi (the bacterium that causes Lyme disease) at the time they were enrolled at ~6 months of age.
- That’s good to see. Diagnostic tests are rarely perfect and one thing we pay attention to is the “specificity,” which is basically how often the test provides a false-positive result (i.e. a positive result in an individual that is actually negative). That’s particularly important for a disease that’s uncommon, since the lower the specificity, the more likely a positive test result in an individual patient isn’t real. We suspect the test that we use (SNAP 4DX Plus) is actually better than the company claims, and I think these results support that. If the specificity was really 96%, for example, we’d expect 4 false positive results per hundred tests. Since we had no positive results in 174 dogs (that truly shouldn’t be positive at that age), that’s encouraging.
One year follow-up testing has been done on 25 puppies, and 2 have been positive to antibodies against B. burgdorferi.
- That’s a fairly impressive number, actually, since I wondered whether we’d see any in the first year, That doesn’t mean they have Lyme disease or will develop Lyme disease. It means they were fed on by an infected tick and that their body mounted an immune response, which is normal. This study will help us more accurately define what happens in response to exposure, but current evidence indicates that disease occurs in a small minority of exposed dogs.
Most owners (95%) recalled having a discussion about tick prevention with their vet, and 85% had received Lyme disease information. In contrast, only 7% of owners recalled any discussion about Lyme disease with their physician.
- Since B. burgdorferi exposure and Lyme disease occur in parallel in dogs and humans (both get infected the same way – by being bitten by an infected tick), this shows a concerning education gap. Vets aren’t (usually, I assume) talking to people about preventing Lyme disease in humans, but the messaging around canine Lyme disease prevention and the increased awareness of ticks and tickborne disease provides indirect education to owners. While canine tick preventive and vaccination don’t apply to people, raising awareness about tickborne disease and general tick avoidance practices (e.g. avoiding high risk areas, tick checks) protect both people and animals.
We’ll have more to follow about this study as time goes on. For more information about the lifetime study, please check out the study website: https://www.canadian-k9.com/