Wednesday, January 05, 2005

Heartworm Concerns

When I first adopted my boys, a coworker pulled me aside and said "be sure to get your cat the heartworm prevention medicine." For those of you who are unfamiliar with heartworm,'s Cat Guide, Franny Syufy, defines heartworm as:

A large, parasitic worm that lives and reproduces inside the heart of a cat, generally in the right side of the heart and the lung. Heartworms are transported from one animal to another, through mosquitos . . .

Surfing the Web, I found a very comprehensive page devoted to feline heartworm at the American Heartworm Society. I also found a great summary of heartworm problems in both dogs and cats in's veterinary section. I read this intriguing Q&A on feline heartworm from a vet. I even landed on some disgusting pictures of heartworms eating away at a cat's heart, but I'll spare you the link to that. Let's just say that I'll never look at spaghetti the same way again.

Here's a quick summary of the things I learned from those articles and others:

  • Cats are at much lower risk (10% as likely) to get heartworm than dogs
  • However, once heartworm is contracted, most treatments for cats are ineffective.
  • Indoor-only cats are less likely to get heartworm, but it is possible
  • Several prevention products, most notably Heartgard, can be administered during mosquito season.
While my cats never go outdoors, I think it would be foolhardy to assume that they will never be bitten by a mosquito. We open the windows during the summer and mosquitos do come in on rare occasions.

So my question is this: would it hurt to give my boys a treatment like Heartgard? Is there a long-term risk or side effect? If not, I'd like to get the boys on a program, because, even if the risk is tiny, it's not a risk worth taking.


Thumper said...

I've had cats all my life--43 years--and none of them have ever been given treatment for heart worm. All the dogs have. Anytime you administer a medication there's the potential for side effects... I think in this case it's a weighing of the very very small chance they'll get heartworm vs. the expense of the medication and the risks of medication.

IIRC, one of the biggest problems with heartworm medication in cats is copius vomiting. While that in itself doesn't seem like a big deal, the resulting dehydration could be.

But honestly, this is something I'd discuss with a vet. There might be a higher incidence of feline heartworm in your area that makes the risks acceptable. That's something you would need to know to make an informed decision.

Peggy said...

Avram, I would agree with Thumper. Heartworm in NYC apartment kitties is highly unlikely. The Pet Education article has some great info on cat heartworm. At our shelter, we don't give heartworm a second thought for our cat intakes, and to my knowledge, we've never had a case in the last few years. I think this is one thing you really don't need to worry about, but of course, ask your vet for a professional opinion.

You need to post the link to Thumper's Psychokitty blog in the margin--it's hilarious!