Sunday, September 14, 2008

The Variety of Life

This is Ruby. She’s a rescue dog. I don't mean that she'll save you in the event of an avalanche or anything, just that she came from of those animal rescue outfits. She came to live with us about three months ago and endeared herself to us in short order.

We’re told that in her former life she belonged to an elderly couple. While the wife was in the hospital for surgery, the husband was driving to visit her when he had a terrible car accident and was hospitalized himself. There was no one to take care of Ruby and so adoption was the only choice.

That absolutely must be the story they tell everyone about every dog. I mean, no way right? That one just reeks of urban legend and I’m not buying it.*

Whatever her story, my guess is that her past was not abusive as much as it was neglectful. She doesn’t flinch when you go to pet her like some abused dogs. She just wants to be around people. Always. Every second. And right under foot too.

So everything is going well and after about three months we go to the vet for some routine medical stuff including a heart worm test. And the test comes back positive. Somehow, between the time that the rescue outfit tested her and got her onto preventative meds, Ruby was infected.

Just rotten luck really.

Anyway, she’s being treated and the vet is optimistic about her chances. But heart worm is a pretty serious disease and it will kill a dog if left untreated. And the treatment itself carries a weird risk also.

But what’s really crazy is the life cycle of these parasitic roundworms.

To become infected with heart worm (dirofilaria immitis), a dog (or cat, wolf, fox, ferret or sea lion) MUST be bitten by an infected mosquito. That bite will cause the larval stage of the heart worm to infect the dog.

As the larvae mature, they migrate to the muscles of the chest and abdomen, concentrating typically in the heart and arteries around the heart. They simply bathe in the blood flow absorbing the nutrients they need to survive. At full maturity, they are about the size of a piece of spaghetti.

They bear baby heart worms called microfilariae by the thousands. Every day. The host’s bloodstream becomes crowded with them. But at this stage, the microfilariae don’t any damage. Until another mosquito bites the dog.

The microfilariae then infect the new mosquito, molt into a new life stage and migrate to the mosquito’s salivary glands and wait. The mosquito then bites another dog and injects the larvae where they migrate to the heart, grow to the size of spaghetti, produce tens of thousands of young and then another mosquito comes along…

The fact is, they must spend two to six weeks inside of a mosquito in order to advance to the next life stage and become infectious..

Isn’t that insane? The bottom-up design strategy of evolution makes for some crazy shit!

So that’s what we’re up against with Ruby. The treatment involves the injection of Immiticide…a nasty compound that kills the mature worms. The risk of the treatment is that once the worms die, they can detach from the heart, get into the lungs and cause pulmonary embolism and the dog dies.

To reduce this risk, you have to keep the dog inside and as calm as possible. No exercise whatsoever. The heavy blood flow associated with increased activity greatly increases the chance of embolism.

After five weeks of trying to keep a three year old lab calm and inactive, you go back for another shot of Immiticide. Then the next day you go and hit ‘em again with a third shot of Immiticide – One-two-Bam-Bam. And then they give a second medication to kill off the microfilariae. Five more weeks of calm and quiet living and, hopefully, your dog is heart worm and microfilariae free and good to go.

So far so good. I’ll keep you in the loop with our progress.

*One quick note about the rescue agency we dealt with, PAWS New England. They are good people doing good work and they have been completely upstanding about all of this. They are paying for Ruby’s treatment. You could do a lot worse than sending some of your charitable contributions their way.

1 comment:

molly said...

ohhhhh, that's so terribly sad. and the sad eyes in the photo don't help the sad bit. my brother was actually stung by four of those infected mesquitos and...well... i'll tell you the story sometimes. it's beyond gross.