Expert: Jana Connell RVT, CVT - 5/12/2011

Question
Hello Jana,

I brought my kitten to the vet for her last set of vaccine, and my vet mentioned heartworm prevetion. He said unlike dogs, heartworm is untreatable for cats and could be very dangerous, and heartworm is transferred by mosquito bites so although my kitten is strickly indoor, there is still a chance she will get it. However, he also said it's less common for cats to have heartworms.

So I did some research on cat heart worms and basically confirmed what he said. But most of the articles I can find are about heartworm symptoms and treatment, very few talk about prevention and what's the odd a cat may get it. From the limited sources I can find, it seems the prevention (pills or shots) have to be applied every month, which could be a real hassle to me. Also my kitten is only 4 month old, so I'm worring the side effects of the med will do more harm to her than good. I cannot find any discussion on the side effects of heartwormer, but, well, every med has side effect.

So, could you share some knowledge on heartworm prevention for cats? Do you think I should go for it or chance is too small to worry about? Thank you very much!

Answer
Well I have seen cats with heartworms more than once, and it's not a pretty sight. I have my cat on heartworm prevention, and I give her a chewable Sentinel tablet that is for dogs and used off label for cats. She is flea and heartworm free as a result.

Cats that are indoors can get heartworms and even leukemia! Other cats can wander by and unless you live in the 10th story of a huge apartment complex that is a risk.

The pills I give are small and if you start your cat now, she will get used to them and chew them up. They taste good to the cat. There is also heartworm pills just for cats made by Heartgard. I prefer the Sentinel for the flea protection as well.

There are no side-effects from what I use because the ingredient that prevents the heartworms is basically an antibiotic that they found works better on preventing heartworms then as an antibiotic and the flea medicine is a hormone that only disrupts the fleas life cycle. It only affects creatures with chitinous shells (the hard body shell that fleas have).

I would would start her on it and yes, it's a monthly pill for life but oh how it will help extend her life!! You don't want to risk her getting heartworms because your vet is right- there is no treatment and cats will just drop dead from it.

We saw this for years and years in cats before we knew it was heartworms causing it. This was long before they had the tests they do now or even knew that cats could get heartworms! Because a cat is so different from a dog the worms affect them much differently.

Here is the definitive authorities on feline heartworm:

http://www.heartwormsociety.org/pet-owner-resources/feline-heartworm.html

I would not use the shots by the way. The pills are much easier to deal with and don't run the risk associated with injections.