The ' new strain of parvo ' hysteria and why it should stop

Suddenly all the dog blogs and email lists are going crazy over a supposed new strain of canine parvovirus (CPV) that the current parvo vaccines don't protect against and that is deadly to adult dogs as well as puppies.



These reports all cite a press release from Oklahoma State University, dated January 14, 2008, as saying that OSU has identified a new variant of CPV, known as CPV-2c.



Is any of this true?



Well, there's a press release.



And there's a strain of parvo that's not new as in, "just discovered yesterday," but it's new as in, "it's eight years old now."



And it's new as in, "we knew it was common in Europe but we only just looked for it in the U.S. and found it here":

“We were quite fortunate to discover this variant,” explains (Dr. Sanjay) Kapil. “It has been known for six years in Italy but nobody paid attention to it here until we found it last year.”

Nobody except the other researchers who had written about it in a bunch of places including here (2007; U.S.) and here (2006; Prague) here ("Management of canine parvovirus type 2 in a kennel environment"; Toulemonde CE, Brunet S, Cariou C, et al.: 2006, Proc Journe´es GTV, Dijon, France; Spibey N, Greenwood N, Tarpey I, et al.) and here (2001; Japan) but okay.



And okay, probably not really new in the U.S. either, given that it's apparently everywhere already:

“What was so interesting was that after we described this disease, we ended up with samples from other locations here in the U.S.”

No, the only thing new here is this press release [UPDATED WITH NEW LINK HERE]. And perhaps this one line from it:

A patent has been filed on the characteristics of the U.S. CPV-2c.

But the press release is full of scary little phrases like "six hundred dead puppies in one night" and mention of an adult dog (one single dog) who had been vaccinated multiple times and still came down with parvo:

“Sometimes we received ten dead puppies a day. We are working with several veterinarians and are receiving samples from cases with a history of vaccine failure,” continues Kapil.

I'm going to guess they were getting "ten dead puppies a day" because people are sending them those for purposes of their research, not because there has been any increase in the number of puppies getting sick with parvo, a disease known to be particularly common in puppies.



Back to the release:

According to Kapil, the disease presentation is different in that normally parvovirus does not affect adult dogs only puppies. However, since publishing their findings, the OADDL has received samples from adult dogs in Minnesota.



“Veterinarians are confused because the in office diagnostic tests come up negative,” explains Kapil. “Clinically it looks like parvovirus so they send it to us. The OADDL tests it and it is parvovirus. Now world-wide (except for Australia), this particular variant can attack the heart and intestines.”

Let's start with this: adult dogs have always been able to get canine parvovirus. It's simply more common in puppies, because there are difficulties in successfully immunizing young puppies against this disease -- not just the "new" strain, but all known strains. But most adults are vaccinated for parvo, and since the vaccine is extremely effective, even those who don't continue getting so-called "booster shots" remain immune for many years, most likely their lifetimes.



The problem of a very, very small number of dogs who cannot be successfully vaccinated for parvo is not new, and has been established long prior to this in the veterinary literature.



All strains of CPV attack the intestines, and they can all attack the heart in young puppies. I have no idea why this is being presented as some kind of "stop the presses" news; it's not.



What is news is that there are some qualities about this strain that make its laboratory diagnosis difficult, and yes, vets and veterinary labs do need to be aware it's out there and account for it.



What this release is not saying is either of these things:

• That there is a new strain of parvo that we have no vaccine for



• That you should be sure to vaccinate your dogs more for parvo because of this new strain

This strain of parvo has been around for eight years now:

In 2000, a new variant of CPV (subsequently named CPV-2c) was detected in Italy and is now widely distributed and cocirculating with types 2a and 2b in that country. The CPV-2c has also been reported from single outbreaks in Spain and Vietnam.

The vaccine we currently have, as well as natural immunity in dogs who have recovered from parvo, both produce immunity to this strain. ("Canine parvovirus type 2 vaccine protects dogs following challenge with a recent type 2c strain;" Proceedings of the World Small Animal VeterinaryAssociation Congress, Prague, 2006.)



The study on which the OSU press release is based says the exact same thing:

The original CPV type 2 based vaccines have been shown to provide protection against the Italian isolate of CPV-2c.

In addition, in a study at the University of Georgia in 2006, the dogs with what they found out was CPV-2c and the dogs with other strains of parvo all had similar vaccine histories. I want to go through this information carefully:



Researchers tested 33 samples from dogs with parvo; 27 were found to be positive for CPV using a test known as "real-time PCR."



Of those, seven turned out to be the CPV-2c strain. ALL of those dogs were puppies. They had all been given vaccines, of several different brands, between two and four times.



Of the dogs who had the older strains of parvo, some of them were young adults (14 months was the oldest), and all had been vaccinated with varying brands of vaccine between two and four times.



In other words, the only difference between the two strains as far as the vaccine went is that the dogs in this study with the new strain were younger than some of the dogs who were sick with the old strains.



It's almost certain that every one of these dogs became ill because their parvo vaccines were given at inappropriate intervals (too close together), or the final vaccine was given too young. The difficulties of successfully vaccinating puppies for parvo are well-established.



Since the dogs who have disease from parvo of any strain have the same kinds of vaccination histories as the dogs who have CPV-2c, there's nothing to suggest that the current immunity, from vaccine or natural infection, doesn't cover CPV-2c, which has been widespread in Europe as well as the United States for years now.



Unless you're dealing with what test to use to diagnose parvo in a sick dog, and where to have the test done, this information means nothing. It doesn't mean your dog's immunity won't protect him.



It certainly doesn't mean you need to re-vaccinate your dog; the logic of this suggestion, which I've seen dozens of times in the last two days, really escapes me, since if the vaccine works against this strain (which it does), your dog is already immune, and if it doesn't, re-vaccinating him won't do anything.



In other words, folks, if the existing vaccine didn't cover the new strain (which it does), re-vaccinating your dog with the existing vaccine wouldn't make one damn bit of difference. It would literally be no better than throwing a virgin in a volcano to placate the fates.



In all honesty, I'm not surprised the loaded language in the OSU press release scared people, with all the stuff about 600 puppies dying in one night and mentions of "vaccine failure" and dead adult dogs. And yet... if you really look at the various studies, what you see are the usual kinds of vaccine failure from maternal antibody interference. You see dogs who are not vaccinated at all. You see dogs who got sick so soon after being vaccinated that they were clearly incubating the disease already.



The researchers themselves say this -- say there's no evidence this strain has evolved out of the coverage from existing vaccines. The very fact that this strain is so widespread, and is being found all over the country, tells us this is just another strain of CPV that's out there, of interest to virologists, yes, but its practical importance? Other than the fact that one of the common lab tests for parvo can miss it, not much.



So enough, already. Sure, one day we might have a strain of parvo that mutates beyond coverage by existing immunity. I'm glad that researchers are watching out for that. I certainly want labs to know when strains evolve beyond the ability of some of their tests to detect.



But all we're doing with this hysterical "sky is falling" reaction, our insistence there's a new strain of a deadly disease and our dogs aren't protected against it, is spreading false information and scaring the crap out of people.



So can we stop all this terror and fear on the lists and blogs?

Comments

[nancy freedman-smith]

Dam girl. You are good!!!

Thanks for the great info.

[JenniferJ]

Thank you!



I will be putting a link to this on my breed forums, with luck, it will settle everyone down

[Susan G.]

Once again Christie lends a calming, rational voice to the internet madness. Thanks for the post. What I want to know is what "breeder" has 600 puppies?

[katie]

Thank you. Thank you thank you thank you. A much needed dose of sanity, indeed.

[Judith Alta K]

I hear cash registers ringing at the vaccine manufacturers.



Sounds like scare tactics to get people to poison their poor dogs in droves.

[BJ Page]

Great post, Christie.Well done.

Sincerely, BJ

[liz]

Great article, Christie, thank you! I'm off to find a virgin and a volcano ;)

[Christie Keith]

Snort, good luck with the first, Liz. ;)

[Deb Schuster]

From a scientific, evidence-based perspective, the Prague study provides totally inconclusive results as a group of six dogs does not constitute a study. Frankly, it almost borders on anecdotal!



"Twelve seronegative beagle dogs were divided into two equal groups." ("Canine parvovirus type 2 vaccine protects dogs following challenge with a recent type 2c strain;” Proceedings of the World Small Animal VeterinaryAssociation Congress, Prague, 2006.)



What needs to be understood here is that parvo evolves and mutates the same as human influenza and updated vaccines are required. Humans receive a new formulation of flu vaccine every year. WHY IS THAT?



"Nobody except the other researchers who had written about it in a bunch of places including here (2007; U.S.) and here (2006; Prague) here (”Management of canine parvovirus type 2 in a kennel environment”; Toulemonde CE, Brunet S, Cariou C, et al.: 2006, Proc Journe´es GTV, Dijon, France; Spibey N, Greenwood N, Tarpey I, et al.) and here (2001; Japan) but okay."



Regarding the above statement...your source refers to parvo 2, not 2c. Ddo some research on avian flu so you can understand how viruses spread from bird to bird and country to country. The spread of parvo 2c is spreading in exactly the same way and appears to not have present in the US until recently.



Don't dismiss the OSU press release as the foundation for a pharmaceutical cash cow. It is real and dog owners need to be aware.

[Christopher]

That one caught me off guard, especially the paragraph where it specifically states that this variant is different in its ability to infect adult dogs.



"According to Kapil, the disease presentation is different in that normally parvovirus does not affect adult dogs only puppies. However, since publishing their findings, the OADDL has received samples from adult dogs in Minnesota."



That level of distortion is criminal.

[Christie Keith]

Christopher, I agree... although it's not a direct quote from Kapil, and I have no idea of the context. I mean... there are adult dogs with the older strains of parvo, too. I would say that USUALLY parvo only affects puppies, but that's because most adult dogs are immune to parvo, not because a non-immune adult can't normally GET parvo.



I feel that the combination of the wording of the press release and the just plain WRONG information being spread by so many people right now -- going far beyond anything implied in the release -- is doing a real number on people's heads.

[Cindy Frost]

Years back while living on reservation land in MT. where few did vax's, folks came to see a litter, two days later, Parvo. Vet. checked with

a school chum who'd become leading resercher at

Cornell U. for Parvo. Advise: 1st shot 5 wks.

2nd at 7 wks. Product Proguard 5. I've stayed with this, never again have I seen Parvo and

I've shipped puppies to 39 States...never a

puppy demised from Parvo.

[Christie Keith]

From a scientific, evidence-based perspective, the Prague study provides totally inconclusive results as a group of six dogs does not constitute a study. Frankly, it almost borders on anecdotal!



I completely disagree with you here. This was a challenge study in which 100 percent of the vaccinated dogs were protected and 100 percent of the unvaccinated controls were not, when challenged with the CPV-2c virus after being vaccinated with current vaccines.



When you have very small numbers in a study, what you want to see is a very strong pattern to counterbalance that. We have that here. In fact, while it would be even more striking if the numbers were higher, that 100 percent exceeds what you normally see with parvo vaccine against the older strains in similar challenge studies.



What needs to be understood here is that parvo evolves and mutates the same as human influenza and updated vaccines are required. Humans receive a new formulation of flu vaccine every year. WHY IS THAT?



The influenza virus genome is extraordinary for its plasticity -- it has an infamously high mutation rate.



The influenza viruses, unlike CPV, have evolved many ways of circumventing the immune system. Changes in the virus antibody-binding sites enable the virus to "outsmart" the immune system by making it think this is not the virus that body is immune to.



In addition, the influenza A virus -- which can infect hosts of many species, including humans -- mutates easily into new subtypes. This means it loves to swap genes with other influenza viruses that are present in the same host.



This is where we got the "avian flu," and many other type-A influenza viruses. These viruses develop all of a sudden and are highly unpredictable, so when a new subtype of Influenza A emerges, it's a cause for fast action and grave concern.



Contrarily, while canine parvovirus is a relatively new virus and certainly worth watching, since its emergence around 30 years ago it's actually been quite stable. COMPLETELY unlike influenza viruses, the parvo strains, including CPV-2c, are around 99 percent homologous, so they will be cross-protective. Immunity from parvo vaccines or natural infection still covers the few new strains that have been identified. So the situation is very unlike that with the influenza viruses.



Sure, I'm glad they're checking. Sure, as I said, a canine parvovirus that mutates beyond the coverage of immunity could come along. But this isn't it. No researcher is saying it is. And it's in no way comparable to the human influenza viruses in that regard.



Regarding the above statement…your source refers to parvo 2, not 2c.



This is incorrect. All those studies were looking at parvo 2c. I have seen the actual studies, even in those cases where they were not available online and I had to link only to abstracts and citations.



Also, ALL the studies on canine parvovirus disease in dogs will look at CPV-2, as CPV-1 is not "parvo" as we know it... it's minute disease in dogs and not the dreaded canine parvovirus we fear. So a study saying it's looking at CPV-2 is the norm -- CPV-2c is also a CPV-2 virus. It's not another virus, it's the category of virus to which CPV-2c belongs.



Do some research on avian flu so you can understand how viruses spread from bird to bird and country to country. The spread of parvo 2c is spreading in exactly the same way and appears to not have present in the US until recently.



CPV-2c is NOT spreading similarly to avian flu, it is not mutating similarly to avian flu, and depending on how you define "until recently," is not some horrific new OMG THE SKY IS FALLING virus in the United States. It is not a plague of locusts, and whatever the press release said or implied, the hysterical statements made by people all over the Internet are demonstrably without basis at this time.



Don’t dismiss the OSU press release as the foundation for a pharmaceutical cash cow. It is real and dog owners need to be aware.



CPV-2c is perfectly REAL. It's just that immunity to older strains still covers this one, it's not as "new" as it's being presented as being, and people are fear-mongering about this virus all out of proportion to any actual information that's out there.



The "news" in this press release is not about vaccines and not about immunity and not about the severity of the new strain, because there's no news there.



The "news" is that this strain can outwit some of the existing TESTS for parvo in dogs. CPV-2c differs by a few amino acids from the others, which is just enough to affect what's known as a "neutralizing epitope" of the virus. The current fecal ELISA tests, which primarily use an antibody that is specific for a single epitope, will miss any variants altered at that epitope. But that's not about immunity, or vaccines. It's about DIAGNOSTICS.



Hence my suggestion that the key line in this press release is about the patent application, not because I'm suggesting it's "the foundation for a pharmaceutical cash cow" but because that's the scientific importance of this information. THAT is the news.

[Elizabeth]

Well written article, commonsensical!!!

[Lyn Kargaard]

I wonder about any breeder who has 600 puppies at one time!!! What other issues were manifested? This sounds like a puppy-mill and what little I know about puppy-mills suggest the care given and the breeding stock can be (may not be, I realize) responsible for health issues. 600 puppies die in one evening and one breeder--that is a problem in and of itself!

[Lori]

I believe I have seen this strain at my clinic. We had an adult dog- about 8 years old, stray from the shelter that presented in life-threatening shock. The standard Parvo test was negative, but he had all the standard clinical symptoms. This dog required plasma transfusions to survive this and several days of ICU care.

We called it parvo, but could never prove it through standard diagnostics. He survived after a few weeks in the ICU and lots of donated money.

[Donna Miceli]

When I first read the OSU article, I immediatly noticed that it was implying that the original Parvo didn't effect adult dogs. From experience I knew this was wrong. When Parvo fisrt appeared, before it was identified, whole kennels, adults and puppies, were dieing. During the most reacent major outbreak in my county, one shelter lost all it's puppies, but the other shelter lost half it's population, adults and puppies.

Once I read that (lie? misinformation?) all the claims in the article became suspect.

I know that there is a new Corona virus out that is upper respiratory, not intestinal. I know this because two of my dogs were the first on the west coast to be diagnosed with it. Since it also came from Europe and has been seen primarily in Italy, I wondered ii the writer of the article got the two dieases confused.

[Pat Anderson]

Having just had two outbreaks of this new parvo ( I do not know your definition of it but mine is it is new if not covered by the vaccine ) that affected many dogs, both adults and pups in the 3 to 4 month range, I believe it should be talked about and people should understand that there is no vaccine and pups are not as easy to bring through the disease as adult dogs so more caution for a longer period should be taken to protect the older pups. We have a lot of pups usually but they are fosters not bred here and I will take all caution to protect them from this disease that I can.

[Christie Keith]

Pat, I understand you experienced illness in your dogs, and I'm sorry for what you and they went through, but you're mixing up a lot of different concepts here.



Did you have a test done -- electron microscopy, PCR -- to determine that the symptoms were caused by CPV-2c? Why do you think they were?



Since research has shown that the current vaccines DO protect against CPV-2c, and you had this problem in multiple dogs, the chances that it was, indeed, caused by this strain are so remote as to be nearly impossible. Sure, you could have had a house full of non-responders, but in that case, they'd be just as susceptible to parvo of the other strains, too. And since you're fostering, not breeding, I'd have to bump the odds of them all being non-responders all the way to zero.



Did lab tests show these dogs were leukoenpic? What diagnostics showed this was parvo at all, and not some other form of intestinal disease?



Bad information and over-reacting doesn't protect dogs; only good information does that. That's why I believe we need to be careful that what we say is accurate.

[Michelle Gaden]

My 8-month old (unvaccinated...STUPID,STUPID, STUPID) female mixed-breed went to the vet April 13 for vomiting, lack of appetite and lethargy. Three negative parvo fecal tests left vets mystified. She was admitted to the hospital. Two days later my other 8-month old didn't eat breakfast. I immediately took him to the vet; he had no fever and wasn't acting very sick so they sent me home with amoxi and doxy. He died less than 48 hours later. Three days ago, my four 8-week old puppies started exhibiting symptoms of this as-yet undiagnosed disease. (They had their first puppy shots two weeks ago) Lost one of them overnight, took the other three in the next morning where they tested positive for parvo, so I left them there for treatment. Lost one of them last night and expect to lose the remaining two by the time I get to the vet clinic tomorrow. The first dog to get sick, Sissy, recovered after 12 days of hospitalization and is now staying at a friends house until her vaccinations kick in. There is still not a definitive diagnosis for her illness. For me, the biggest problem with this "new" strain is that it does not show up on the ELISA. I would have sought treatment for all my dogs immediately had I known what I was dealing with.

[Jeanette Harper]

Three months of pure hell. I had a litter of seven boxer puppies(healthy puppies). Took them into vets to have their tails and dewclaws done. Two weeks later one died.(Did not suspect parvo at this time) At six weeks of age I took the others in for their first shots. Nine days later, first puppy comes down with parvo. And it continued until all six came down with parvo. All six had to be hospitalized. Long story short, Four came home, two had to be put down. One with a broke back, which vet could not explain(she came home,but progressively lost control of her back legs)within two weeks I had to take her back to vet to be put down.How this litter got parvo, vets can't explain,as they were born and raised in my home, and never left until I had their tails docked and dewclaws removed. Never on the ground. Now Vets trying to tell me it's a new strain of parvo going around. But thanks to your article I now know better. Thank you. Still suffering, as I can't sell fourteen week old puppies that have had parvo. Not a puppy mill! This was my first litter,and I waited until my female was four to breed her. You know, I just want someone to take responsibility for this.And I know they probably never will. I'm just tired of professionals blowing smoke up my ___,trying to cover theirs.

[Ann]

I have been doing rescue work for 6 years. We have had the same number, on average, of parvo cases in puppies over this time period. We have had an increase of adult parvo cases over the last year. We have personally had 5 cases of adult onset parvo (12 months old or older). In all but one case we had documented vaccines either given 3 times or 4 times, 3 dogs were fully vaccinated by a veterinarian and not by shelter personnel. In addition to these cases, we have cases in affiliated rescues totaling another 6 in the same time period. It really does seem like there is something going on out there. While my numbers may not seem statistically significant, they are to us - the worker bees in the trenches.

[Tim Holt]

We had a 9 month old puppy that was vaccinated by the vet on the vets schedule...he died last night from Parvo...said a new strain...I took him to the vet when he first started acting lethargic..was at the clinic on fluids and treatment and died overnight after the third day.... if this isn't real than what the heck happened? I took him no where except a walk down our street nightly...I can't figure it out

[Christie Keith]

Tim, I'm so sorry for your loss.



There really is no new strain of parvo that isn't covered by the current vaccines, but that doesn't mean his vaccines were effective, nor does it mean he actually had parvo at all.



So without a lot more information, it's impossible to say what happened to your little guy, or whether or not he even had parvo. Did you have a post-mortem exam done? Was the puppy leukopenic? How old was he when he had his last vaccination?



None of these questions can bring him back, but they might help protect a future puppy or dog.

[Jacq]

Parvo 2c is real. Kapil is correct in his findings- read the article people. And not all CPV vacs fully protect against it.

cliff notes version on history of CPV:

when symptoms first 'noticed', not diagnosed, in dogs in early 1980's, dvms had no clue what it was. DVMs later state virus resembled panluekopenia/ a cat virus. DVMs began vaccinating dogs with the panleuk cat vaccine. It worked.

Idexx tasts as of 2009 were not detecting parvo (CPV)2c. Parvo 2 was orignal name. It mutated over time to parvo 2a, 2b and now 2c. Look at what CPV strains are in vaccines and which cross protect. Pfizer and Merial are CPV2/2a strains and do NOT cross protect well against 2C, 50-60% efficacy. Intervet Schering Plough is CPV 2b strain and cross protects extremely well agianst 2c, studies show 100% efficacy. FT. Dodge, now B.I., is a differ 2b strain and cross protects against 2c, 90% effective. Upon necrospy of adult dogs, CPV 2c is being detected where Idexx snap tests, ELISA and PCR missed.

[Francine]

My dog just died from this new strand.. and yeah is worse the new old one.... and people should be a little concerned by it.. since its the winter time in el paso. texas. and they are getting it. when CPV is a spring summer virus. our vet doesnt understand what is going on... and it takes longer to kill your dog. and our dog had half of his shots, he was only a puppy. be careful

[Christie Keith]

Francine, I'm very sorry for your loss, but the old strain kills puppies, too, and it's COMPLETELY COMMON for "half-vaccinated" puppies to die of parvo, and suffer severe complications.

There remains zero evidence that this "new strain" is worse than the "old strain," nor that it's any harder to protect against with vaccination.

Again, I'm so sorry for your loss of your puppy.

[john burns]

Have anyone ever heard of vaccines causing parvo? i rescue puppies and it seem like everyoe once in a while i will get 1 or 2 puppies out of a litter that dies from parvo and the others are fine. clearly its not in my enviroment because i have bought brand new crates and i hold them all for two weeks before placing them. The vaccines i use are called Nobivac