New Strain Of Parvo Hysteria

relax~ it's not so new...

SOURCE

The ‘new strain of parvo’ hysteria and why it should stop
February 8, 2008

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.

the rest:

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.

Good info thanks Suki...