We continue to track cases of canine infectious respiratory disease in various parts of Canada, for what it’s worth. The data are obviously a bit dodgy because it’s primarily from self-reporting, but I think we’re getting some interesting information. Cases seem to be slowing down, but we continue to get reports from the two main areas in Canada (and a trickle from the US). Part of the clustering we’re seeing is probably due to local increased awareness and reporting, but I don’t doubt that a couple of reasonable-sized outbreaks have been ongoing.
Click here for the latest version of our canine infectious respiratory disease complex (CIRDC) map (December 31), now with the ability to display cases reported by month. A snapshot of the map is also shown below.
Here are some additional details from the data we’ve collected via the reporting survey:
65% of affected dogs had been vaccinated against “kennel cough” in the past year.
- That’s not too surprising. Kennel cough vaccines protect against one, two or three of the many potential causes of CIRDC, but not all of the causes, by any means. Furthermore, no vaccine is 100% effective. These data don’t tell us anything about how well those vaccines work (they actually work quite well).
Of that 65% of affected dogs that were vaccinated in the past year:
- 40% were vaccinated orally: The oral vaccine only covers Bordetella bronchiseptica, which consistently comes in as the #2 cause of CIRDC in Canada. It’s a good vaccine for that bacterium but has less coverage than intranasal vaccines.
- 29% got an intranasal vaccine: Intranasal vaccines in Canada cover Bordetella bronchiseptica and canine parainfluenza virus, giving protection against the top 2 causes or CIRDC. Some also include protection against canine adenovirus type 2.
- 35% received an injectable vaccine: Injectable vaccines are less protective when it comes to CIRDC. Oral and intranasal vaccines provide better protection where the infection occurs – in the upper respiratory tract.
- 26% were unsure of the vaccine type: So whether these dogs were truly vaccinated against kennel cough is unclear.
Over half of affected dogs had visited a dog park shortly before they got sick.
- That’s not surprising at all, since CIRDC is spread dog-to-dog, and parks are a place where dogs congregate. Groomers came in as the #2 most common previous contact, followed by doggie day care.
- Since we just looked at sick dogs, we can’t say anything about risk factors (e.g. we don’t know if visiting a dog park was more common among sick dogs since we couldn’t compare them to healthy dogs).
- There were a couple specific parks that were frequently named, so it’s likely there were some true hot spots of transmission at those parks.
Diagnostic testing was performed on 17% of sick dogs, but nothing remarkable was apparent in terms of diagnosis.
- That’s actually a pretty high percentage for testing in cases like this. Testing isn’t commonly recommended for routine cases of CIRDC since the cost is hard to justify where there’s little impact of test results on individual patient care.
- Testing is more useful when there’s an outbreak (to figure out what the culprit is and see if there are any control measures that might be applied), with imported dogs (worried about bringing in influenza strains), kennels (outbreak potential) and breeders (outbreak potential, risk of more severe disease in young and pregnant dogs).
- Limited test results were provided on the survey but nothing remarkable was present.
Most of these outbreaks of CIRDC die out over time and we never find the cause.
- Canine parainfluenza is always high on my list since it’s common (common things occur commonly) and can be missed with routine testing because the virus isn’t shed for long. By the time the dog is taken to a veterinarian and sampled, PCR tests looking for the virus may be negative (and other approaches like antibody-based testing aren’t usually done).
- A “new” or (more likely) established but unknown cause of illness is certainly possible. There are undoubtedly many canine respiratory viruses out there that we don’t know about.
- Introduction of canine influenza from imported dogs is always a concern. It’s a “foreign” disease, but canine influenza was introduced to Ontario a few years ago, and was ultimately eradicated (as far as we can tell). Here, since there haven’t been any positive test results, it’s unlikely to be the cause. That virus is shed for a while in infected dogs, and I’d expect to see a positive result with a reasonable number of tests. Introduction of influenza into areas where few to no dogs have immunity to the virus would almost certainly result in more widespread disease. So, I think flu is pretty unlikely here, but the potential for flu is a reason to test. We’ve shown it can be controlled when it’s caught early, but if it’s not, it can cause a lot of damage.
Disease tracking like this won’t provide clear answers, but helps identify and refine things we need to look at, so I think there’s a role for it as an easy, low-cost surveillance tool.