New Canine Distemper Strains in the News: Real Threat, or Scare Tactic?

Yesterday afternoon, one of our AVMA Facebook page friends posed an intriguing question:

Does the AVMA have any insight as to what is happening with the Distemper virus strains that are hitting the news media? Clients where I work are asking questions, and I’ve been researching but just coming up with OSU doing research at this point. Thank you!

Can you say, “Huh?” Hmm, I thought…I’m not aware of any new canine distemper virus (CDV) strains causing problems, but maybe I’ve missed something. Sure enough, thanks to all-knowing, all-seeing Google, I found online news reports of “2 new strains of distemper.” Being the skeptical person that I am, I wasn’t about to take these articles at face value, so I went to the experts to get the facts on this rumor.

Enter Dr. Ed Dubovi from the Cornell Animal Health Diagnostic Center, and Dr. Ron Schultz from the University of Wisconsin School of Veterinary Medicine’s Department of Pathobiological Sciences. They’re both very highly respected for their knowledge on a number of topics, including canine distemper. I spoke at length with both of them about the new strain rumor, and here’s the Cliff’s Notes version:  it’s bunk.

OK, so maybe you want a little more explanation.

Yes, we’re seeing a lot of media reports about distemper being “on the rise.” The truth is we don’t have the 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. Periodic distemper outbreaks are observed in wild animals – particularly skunks and raccoons, and researchers and officials are investigating a recent outbreak of distemper in desert kit foxes. Animal shelters in Florida, California and Texas seem to be constantly having outbreaks, as do shelters in many other states, and that’s probably due to a combination of warmer temperatures (that favor the virus) as well as a lack of adequate vaccination in the lower-income areas the affected shelters serve. Dr. Schultz has found during the past 10 years that many of the larger city shelters have approximately 40 to 50% of dogs entering the shelter are antibody negative for CDV, meaning they’ve never been exposed to the virus (either by vaccination or by exposure to an infected animal) and are thus susceptible.  We have better testing methods now, which make it easier to detect the virus, so veterinarians may be seeing the same number of cases they’ve seen in the past, but are better able to confirm the diagnosis. Combine all of this with the insatiable 24/7 news media and the near-instantaneous spread of information and rumors via Facebook, Twitter and other social media, and you’ve suddenly got panic-stricken pet owners rapid-firing questions at their veterinarians.  Most veterinarians have not seen a case of CDV in their vaccinated canine patients.

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. Also, a genetic change in the virus doesn’t necessarily change the virus enough to impact our pet’s health. Regardless of whether or not there are new strains in the U.S., there is no scientific evidence that the currently available vaccines won’t protect your pets. Or, to avoid a double negative and make it more clear, the currently available distemper vaccines are highly effective and will protect your pet in all but rare circumstances  – remember, nothing is 100% when you’re dealing with living beings. Dr. Schultz estimates that 1 out of every 5,000 dogs is incapable of developing an immune response to the canine distemper virus, so there is a low risk of disease despite vaccination, but that risk is nothing compared to the likelihood that your dog will become ill if it’s not vaccinated at all.

The REAL issue here isn’t a scare over “new” distemper strains or a national outbreak: it’s that there are unvaccinated (or inadequately vaccinated) and unprotected pets at high risk of developing a very deadly, yet PREVENTABLE, disease. Distemper is one of the “core” vaccines for dogs, which means that every dog should be adequately vaccinated against distemper. (FYI, parvo, adenovirus and rabies are also core vaccines, and it’s critical to vaccinate your dog against them as well.) For more information on vaccinations, check out the American Animal Hospital Association’s Canine Vaccine Guidelines.

Believe me, we’ll tell you when it’s time to panic over an animal disease outbreak…but this ain’t it. Talk to your veterinarian to make sure your dog is adequately vaccinated for canine distemper, parvovirus, adenovirus and rabies, the 4 core vaccines that every dog should receive. There’s no question that these disease are the perfect example of the old saying, “an ounce of prevention is worth a pound of cure.”

21 thoughts on “New Canine Distemper Strains in the News: Real Threat, or Scare Tactic?

  1. Pingback: Thoughts on Vaccinating at Home | St. Bernard's Animal Medical Center

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  3. @Tom Spape
    The mild winter might actually contribute to the survival and persistence of ticks, so I wouldn’t rule it out. If you’re looking for a second opinion, ask your veterinarian about a referral clinic in your area (probably an internal medicine specialist, to begin with), or contact the vet school at Ohio State. Whatever you do, though, keep your vet in the loop because they will need to be involved in your pet’s continued care. The advantage to the vet schools is that they have a wide range of specialists under one roof.
    Hopefully they’ll be able to figure out if all of the dogs’ problems are related, as well as help find a solution.

  4. Thanks Dr. May,

    It is not tick season and we have had a very mild winter. The only things we can’t rule out are the dogs exposed to something in the ground or in contact with feces of a sick skunk, raccoon or rabbit. Very puzzling and completely crippled are 2 year old dog prior to steroids. However, we just reduced the dosage and she is presenting with similar symptoms again. Can anyone recommend a research institute or agency I can contact for further assistance? Especially incase this would manifests into something worse. Thank you so much!

  5. @Tom Spape
    Tom, I don’t proclaim to be a distemper expert, but what you’re describing doesn’t fit the usual signs of distemper. Given your description of swelling of the joints and spine, plus the close proximity of the dogs, have you considered tick-borne diseases such as Lyme disease(assuming you have that in your area)? It sounds puzzling, and maybe some more tests are indicated.

  6. Recently several neighborhood canines exhibited what appeared to be ACL injuries, but this quickly manifested into swelling in the joints and spine. High doses of Prednisone seem to work initially. Problem is no one locally believes these cases are related. Could this be related to a form of distemper, would it be recognized in normal blood testing? All dogs are current on vaccinations, don’t come in contact with one another, and live within 100 feet of each other. Thanks for any replies. Tom-Northeast Ohio

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  8. Pingback: AVMA@Work – American Veterinary Medical Association » New Canine Distemper Strains in the News: Real Threat, or Scare Tactic? | vmcnotes

  9. @Deb Vaughn
    Deb, can you clarify for me what you mean by “CIV”? To me, that means canine influenza virus, but I didn’t want to assume that’s what you meant. If it is influenza, are you saying that you’ve had dogs react to canine influenza vaccine with illness that resembles canine distemper? If so, I hope the vets reported the cases to the influenza vaccine manufacturer, as well as the USDA.

    And, in response to your query that distemper is being over-diagnosed, we don’t have an answer to that other than it’s possible. We don’t have any data on how many animals are diagnosed with it vs. confirmed to have it. When you’re seeing stories about a rise in a disease, coupled with animals showing signs consistent with that disease, it can be an easy assumption to make. All we can say is that we hope it’s not common, and that vets are doing what they can to confirm their diagnosis.

  10. In New England, we have vets dx’g distemper symptomatically after the CIV was given to some of our adoption pups. We have stopped vaccinating for this. One puppy family was recently told it had distemper, was euthanized, we paid for a necropsy & blood panel- no distemper. I looks to us like distemper is over-dx’d.
    Humane Society for Greater Nashua, NH

  11. Rumors of distemper caused by new “mutant” strains in dogs occur frequently. Following one such rumor, my colleagues and I at the Purdue University College of Veterinary Medicine conducted a field investigation and a controlled epidemiologic study to document the outbreak and identify important risk factors. The major risk factor identified was a dog not being vaccinated for distemper or a dog being incompletely vaccinated for distemper. This increased the risk of distemper 350-fold!! This explained almost all of the known cases of distemper in this Indiana outbreak. The take home message is that distemper vaccines work, but only if your dog gets one. It is far more important for veterinarians and pet owners to ensure that all puppies and adult dogs are vaccinated against distemper following AAHA vaccine guidelines than to worry about the emergence of new strains of the distemper virus.

    Publication: J Am Anim Hosp Assoc. 1995 May-Jun;31(3):230-5.
    Canine distemper infection in pet dogs: II. A case-control study of risk factors during a suspected outbreak in Indiana.
    Patronek GJ, Glickman LT, Johnson R, Emerick TJ.
    Department of Veterinary Pathobiology, School of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907-1243, USA.

    The epidemiologic features of an outbreak of canine distemper during 1992 and 1993 in pet dogs in Indiana are described. Risk factors for disease were characterized using hospital records of private veterinary practitioners. The risk of disease for purebred dogs was 85% lower than the risk of disease for mixed-breed dogs. Lack of vaccination was associated with a 350-fold increase in the risk of canine distemper, and 93.8% of all cases could be attributed to the lack of vaccination. For many of the owners, the cost of medical treatment exceeded the cost of a vaccination program.

    • There is certainly an outbreak of an agressive strain of distemper happening in southern Mexico right now that is infecting vaccinated dogs and grown dogs…….I’m in the process of losing a second (and vaccinated) dog to the virus.
      Local Vets thought it might have been induced by a new rabies vaccination thats making the rounds in the region, due to the tendency of foaming at the mouth and extreme disorientation caused by the new strain. There are reports of it throughout the state of Oaxaca and it appears to be wiping out a noticable portion of the dog population……..It’s a nasty one! I’m watching it destroy my beloved Beagle before my very eyes…..
      I’m not sure if it’s made it to the states or not but beware, it’s here!

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  13. They can measure the amount of protection a pet has. You can always run a titer to see if a pet is adequately protected. This is often done for older animals or ones who have health concerns and may have problems with vaccinations. Most of the ones I have seen in practice do have high enough titers at one and two years post vaccination to not need yearly vaccination. This is a client choice. They should be given this as an option if they have concerns over vaccinations.

  14. @Peter Farrell
    Interesting question, Peter. When I was speaking to Dr. Schultz, he was not advocating for any deviation from the AAHA guidelines. He does stress that for a vaccine to be effective, it must induce immunity (resulting in immunization). We certainly defer to the science-based AAHA guidelines for vaccination.

  15. I latched onto the “inadequately vaccinated” phrase you used. Since Dr. Schulz is the prime mover in the reduce-vaccination-frequency advocates, is this a reference to the possibility that the three year vaccine interval may be inadequately protecting our dogs? It seems to me that perhaps reducing the frequency of vaccination without having any sense of protection, puts inordinate faith in something that you don’t have a way to measure. Just a thought that might be worth investigating.


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