New Strains of Canine Distemper?

Published Feb. 28, 2012

Have any of you run across the reports on the Internet about two new strains of distemper virus affecting dogs in the United States? I have to admit that I hadn’t seen them, but what did eventually catch my eye was an e-mail that I received from the American Veterinary Medical Association (AVMA) in response to the reports. It’s entitled, "False rumors of new strains of canine distemper virus," and goes on to say:

It was recently brought to our attention that there are rumors circulating online about the existence of two new strains of canine distemper virus. These rumors are untrue. After consulting with two experts, Dr. Ed Dubovi (from Cornell) and Dr. Ron Schultz (from the University of Wisconsin), we provide the following information:

There is no data to back up claims that the disease is on the rise on a national level, but there have been many outbreaks of distemper covered in the news media.

Genetic studies of the canine distemper viruses in the U.S. may show strains that were previously undetected here, but it's almost impossible to determine if these strains are newly arrived or just newly detected because of improvements in testing. In addition, minor genetic changes often do not affect the antigenicity of the virus and have no impact on the efficacy of currently available vaccines.

The currently available distemper vaccines are highly effective and will protect dogs against all currently circulating strains of canine distemper virus.

The real issue is that there are unvaccinated (or inadequately vaccinated) and unprotected pets at high risk of developing a very deadly, yet preventable, disease.

Dog owners are strongly urged to consult with their veterinarians regarding vaccination of their dog against distemper and other common diseases, including adenovirus, parvovirus and rabies.

For more information and a "no holds barred" look at this issue, take a look at Dr. Kim May’s blog on AVMA at work.

I can understand why even unconfirmed rumors of a "new" distemper virus would set everyone on edge. Distemper is a terrible disease. Thankfully, I’ve only seen a few cases of it in my career (as the AVMA e-mail says, preventive vaccines are very effective), but they certainly stick out in my memory.

One was in a young, poorly-vaccinated heeler mix. She had a several day history of typical upper respiratory signs — a runny nose, cough, sneeze, goopy eyes. No big deal, I thought, probably just one of the "kennel cough" bugs. After I examined her, I put her in our isolation ward for the day (she was a "drop off" rather than a regularly scheduled appointment). I wasn’t thinking distemper until one of the technicians came back from checking on her and said, "You know, she looks like she feels worse, and now there is some vomit and diarrhea in her cage." Alarm Bells!! We got her through it, but she was hospitalized for about a week and it was touch and go for awhile.

The other case I remember didn’t end so well. He presented after he had developed neurologic signs, and when that happens, the disease is almost always fatal. The owners elected euthanasia.

So, it looks like there’s no need to panic over a "new" form of distemper, but the "old" disease is bad enough to remind us why preventive vaccines are such a blessing.