Monday, June 18, 2007

Two weeks in...

...and I've been woefully tardy in updating you all on my adventures in veterinary medicine. The short, quick story is that I've seen a lot, and learned a lot. Too vague? Perhaps, but so much happens in a day that it gets difficult to get it into some concise, understandable statement. So, I'll just focus on a few cases with big lessons that we all can learn.

Lesson: Vaccinations are a good thing
For most of my first week on the job, I didn't have my official license. This limited a lot of what I could do. I couldn't officially diagnose, treat, or prescribe any medications. I couldn't even vaccinate anything. Therefore, when we had two puppies come in on the same day that tested positive for parvovirus, I volunteered to take care of them.

For those of you unfamiliar with this disease, here is a brief overview. Parvo is caused by a nasty virus that primarily affects puppies. It's main target is rapidly dividing cells in the body, specifically the cells that line the intestinal tract, and bone marrow cells which produce red and white blood cells. As one may expect, the primary signs of this disease are vomiting and diarrhea. These are very sick puppies! The most optimistic survival rates are no better than 50/50. Puppies quickly become depressed and dehydrated, and they simply due not have the body stores necessary to survive for long with the combined anorexia and fluid loss. Due to the bone marrow effects, these puppies have a profound "neutropenia" (low numbers of neutrophils, the "front-line" of the white blood cell defenders). This makes these puppies extremely susceptible to secondary infections on top of the terrible toll the virus itself causes. The virus is very hardy and extremely contagious. It should be considered present in most environments, particularly those in which a puppy with parvo has lived before. Even a puppy that is not yet clinically ill with the virus can shed large amounts in their feces, contaminating even clean areas with large loads of virus. The virus can live for years in soil, not overtly affected by many disinfectants or weather changes.

There are only two good things about parvovirus: (1) it is easy to test for, and (2) it is easy to prevent. If a puppy is suspected of having the disease, all that is needed is a rectal swab and a handy SNAP test. A typical SNAP test is pictured at left (I won't talk more specifically about how those work unless someone asks!)

As for prevention, the current vaccinations -- if used appropriately -- are highly effective in inducing protective immunity in puppies. There are some tricks to it, though. When puppies are nursing, they typically receive a high level of protective antibodies from their mothers. These antibodies do a pretty good job of protecting the puppy. However, they also interfere with vaccines, and will actually prevent the puppy from being able to mount their own, protective immune response to the virus. The end result is that puppies are typically recommended to receive three vaccines one month apart starting at about 8 weeks of age. The idea is that puppies of this age have typically been weaned for about two weeks, and the antibodies they received from their mom are waning. As those antibodies decrease, the puppy will be able to respond to the vaccines and produce their own antibodies.

That is the idea, anyway. So how did my two patients catch parvovirus? Well, one hadn't received their last booster on schedule, and there was some question as to when she had last nursed from her mom and received her first shot. The other puppy had never been vaccinated. He actually came in because he "wasn't feeling good, and, oh, by-the-way, can we go ahead and vaccinate him while he is here?"

Well, long and messy story short, both puppies received treatment and both went home! However, the owners of both puppies certainly received a hit to the wallet as well. Due to the intensive care, fluids, etc, required for treatment, beginning estimates on treating a dog with parvovirus hover around $500. The final bills on both of these puppies were above that. And remember: you can expect to pay all of that and still end up with a dead puppy. These cases are typically very "up-and-down." A puppy that looks like it is doing well one moment will be crashing the next.

So, the lesson here is to make sure you vaccinate your puppy! Vaccines are a lot cheaper than the disease. Even though no vaccine is guaranteed to provide protection 100% of the time, the vaccines to protect against parvovirus are generally thought to be very effective. And your puppy (and your checkbook!) will thank you!

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