This may be my last update on this topic in the short term (unless things change, of course).
The good news:
- Cases of canine infectious respiratory disease complex (CIRDC) around most of the US and Canada seem to be waning, if not back to normal. Since we have no formal surveillance, we have to rely on a variety of data sources for information about this, and none of them (for me, at least) are suggesting that we have anything remarkable going on right now with regard to CIRDC.
The bad news:
- Well, it’s not really bad news, but we still don’t know what actually happened. That’s far from surprising, because with waxing and waning endemic disease conditions like CIRDC, we rarely have a clear picture of what happened and why.
- Everything for me continues to point to a gradual increase in the rate of infectious respiratory disease in dogs over the past couple of years, with the usual intermittent local and regional peaks and valleys. This year’s issues were probably somewhat higher peaks overlaid on a higher baseline, making the issue more obvious and drawing more attention.
What was the cause of the increased cases of CIRDC?
I’m sticking to “the usual suspects, doing their usual thing, just at higher rates.” There’s been a lot of investigation looking for new pathogens and, as far as I know, nothing convincing has come to light. Given the number and quality of the research groups that have been looking, it’s pretty convincing that we don’t have a specific new pathogen that’s caused an outbreak of disease in dogs across North America.
What do we do now?
As with any outbreak, we try to learn some things from the experience:
This situation was a reminder that we don’t have a good surveillance system in place for CIRDC (or most other companion animal diseases). There’s no easy fix for that, especially with no money, so we need to continue to try to leverage the information that is available to better understand disease patterns. We need to do that on an ongoing basis, not just when there’s concern about increased cases, because when we’re concerned about an outbreak, we need to know the normal rates of disease to put things into context.
While we only have vaccines for a few of the important causes of CIRDC (Bordatella, parainfluenza, influenza), they are good vaccines, and we need to optimize their use in dogs that have a reasonable risk of exposure and/or a higher risk for severe disease.
3. Thinking about severe disease
The risk of severe disease in some dogs during outbreaks doesn’t get as much attention as it should; hopefully we’re changing that. In most dogs, CIRDC is a short term, self-limiting problem that’s fairly mild, just like upper respiratory infections in people. However, some dogs get really sick, and some even die. We can’t predict every dog that will have a severe outcome, but we know that there are groups that are at higher risk, particularly older dogs, dogs with pre-existing heart or lung disease, and brachycephalic dogs (i.e. flat-faced breeds). We need to think about minimizing exposure and maximizing vaccine coverage in these groups.
We also need to get people thinking about function over appearance in dogs they are breeding and buying. There is currently a disturbingly high number of anatomically disastrous dogs out there, because people have bred reasonably-functional brachycephalic breeds into extremely flat-faced dysfunctional dogs that have myriad respiratory issues, even without infectious diseases to complicate the situation (see the pictures below). As the French bulldog has shot to the top of the list of the most common breeds in the US, we’re going to see more dogs die from respiratory disease. Not all Frenchies are a mess, but there are enough of them that we see infectious and non-infectious complications in them all the time.
The recent situation with CIRDC also might get people thinking more about their dogs’ social networks and risks, and how to minimize those while having limited impacts on important or enjoyable aspects of dog ownership. We’ll be doing some work on dog social networks later this year, so stay tuned.