Tuesday, March 1, 2011

Parvovirus

I thought this might be an interesting post for ya'll (and an easy "cheat" for me, since I see it at minimum once a week).

Parvovirus first showed its ugly face in the late 60s. At that time, it was an unknown disease. It was incredibly deadly and killed most pets that contracted it. Eventually, its secrets were unlocked, and we began to understand parvovirus. A vaccine was developed against it, immunities were passed from mother to offspring, and the disease became less deadly.

We still see it extremely frequently here. It's a combination of living in a warm, temperate area and the fact that we live in a poor area in the South. Parvo lives in the soil for years and years, and it can be transmitted on the soles of your shoes, hands, or other fomites. Infected dogs shed it in their feces. Parvo incubates for about 3-7 days.

Many people here do not vaccinate their pets, often for financial reasons. Either that, or they administer the vaccines themselves often procured from Tractor Supply. There is nothing inherently wrong with the vaccines from Tractor Supply; they are legitimate vaccines. On the other hand, in the process of shipping, it is likely that they become over-warmed and inactivated. On top of that, I've had owners inform me that they "vaccinated the dog with the liquid - but what was that powder for??"

It is a crafty little virus. It attacks the gastrointestinal tract - wiping out the cells that are crucial for absorbing nutrients and water, as well as crucial for protecting your bloodstream from all the nasty bacteria that live in your intestines. With those cells gone, diarrhea, vomiting, and rapid dehydration rapidly set in. Worse, bacteria translocate across the thin GI wall and straight into the bloodstream. Sepsis rapidly sets in. And parvovirus isn't even done yet. It also attacks the bone marrow cells. Bone marrow makes all the white blood cells that fight off infection. So, when under attack, the white blood cells are not produced. Thus, nothing to fight infection with.

As a result, patients rapidly sicken. Puppies with parvovirus are often feverish, extremely lethargic, very dehydrated, with copious vomiting and very bloody diarrhea. The presentation is very classic, and we can usually make the diagnosis without testing (although we do test to confirm the diagnosis and distinguish it from others such as severe GI parasitism, etc).

Treatment is aimed at managing the sepsis that occurs due to bacterial translocation and neutropenia. Broad-spectrum antibiotics are crucial, as are very aggressive IV fluids to replace the losses through vomiting and diarrhea. Pain relief is also important, as these puppies are often very uncomfortable due to the GI inflammation and diarrhea. Further, the vomiting must be controlled to help prevent worsening dehydration, as well as to help the patient feel better. Unfortunately, the cost of this aggressive treatment usually runs at least $700-1000 for the first 24 hours, then $250-400/day. Couple that with the fact that most of these people didn't vaccinate for financial reasons in the first place, and I do a fair amount of parvovirus euthanasias.

We do offer outpatient therapy to the more stable patients - subcutaneous fluids, anti-emetics, and oral antibiotics to go home. Some patients pull through this way, but the odds are about 50/50.

It can take as little as 48 hours for a patient to turn around with treatment, or as long as a week or more. Yet, we manage to save about 80-90% of these puppies. Some still die - particularly Rottweiler, pit bull, and German shepherd puppies. For some reason, these puppies have a weaker immune system.

The bright side to all of this is that parvovirus is SO EXTREMELY preventable. Puppy vaccines starting at 6 weeks and continuing until 12-16 weeks, followed by a vaccine at a year, then every 3 years will virtually insure that your pet never contracts this disease. So simple to prevent, and yet I see repeat offenders at least once a month at work. No matter what you do, sometimes you cannot get through to people.

Oh well, whatever pays the bills, right??

6 comments:

thelearningvet said...

Wow, perfect timing! I just posted a parvo-related post tonight too! Yours does a far better job of explaining what it is, but I hope you enjoy mine as well (it has a happy ending!):
http://thelearningvet.wordpress.com/2011/03/02/parvo-positive/

voguevet said...

Hah, I hope you were kidding with your last line!

Question: What's the benefit of prescribing oral antibiotics on an outpatient basis? I can understand the need for IV abx to kill any bacteria from the intestines that may enter the bloodstream, but with the destroyed villi, will the oral abx even be effective?

I'm lucky to have never seen a case of Parvo myself, yet...

Chris Bern, DVM said...

Ugh, I HATE parvo. And I 100% agree with all of your points! Well stated overall.

It's so frustrating because this is a very preventable disease, and like most things is far cheaper to prevent than to treat. In my opinion people who don't let a vet vaccinate for this really probably shouldn't have a pet. Harsh but true.

Nicki said...

Parvo sucks. Gotta love the people that don't believe in vaccines and then can't affort to treat their kid's dog for parvo. Yep had that one happen along with all the others that just didn't bother or "have the money" to vaccinate

EQN said...

Would you agree that it's necessary to not only vaccinate the puppy diligently but to also ensure that the bitch has had adequate vaccinations? I ask as this was recommended in our area (which has a high parvo rate).

The Homeless Parrot said...

EQN: Absolutely. For the first 6 weeks of life, all immunity for the puppies comes from mom's colostrum. If mom has never been vaccinated, she will not have any immunity to pass on, and the puppies will be highly susceptible to parvo.