Educate me on heartworm

Let me preface this by saying that I have an unnatural aversion to worms and most invertebrate creatures. Therefore, I've never done any book or internet research on heartworm treatment and prevention because I cannot stomach seeing the yucky pictures. So, please, for my sake, do not post links to photos or photos in this thread.

So my question is this -- the boys have always been on a heartworm prevention pill. I think we've been using Interceptor. Well, I've forgotten to give them their last dose and now we're over 10 weeks past their last dose. I understand that you are supposed to have them tested before putting them on heartworm medicine to make sure they don't already have heartworm.

Is heartworm something that you are not likely to contract in winter, like fleas? It is more seasonal? I have no idea how you get heartworm. I'm just trying to figure out how urgent it is to get the dogs into the vet and get them tested so they can start taking the pills again. We've spent a ton of money of Chester lately so if I can put off another visit for a few weeks, I'd rather do that. Thanks in advance!

Heartworms are caused by heartworm-carrying mosquitoes. It all depends on if the mosquitoes in your area are killed off for the winter.

The life-cycle is like this:

Heartworm infection is spread from animal to animal by mosquitoes. Dogs, cats, ferrets, coyotes, foxes, wolves, sea lions and even humans have all been found to be infected by heartworm.

Heartworms are classified as nematodes (roundworms) and are but one of many species of roundworms.

Adult female heartworms already residing in the heart of the mammal release their young, called microfilariae, into the animal’s bloodstream. Mosquitoes then become infected with microfilariae while taking a blood meal from an infected animal. During the next 10 to 14 days, the microfilariae mature to the infective larval stage within the mosquito.

When the mosquito bites another dog, cat, or other susceptible animal, the infective larvae enter through the bite wound. In dogs, it then takes a little over six months for the infective larvae to mature into adult worms that may live for five to seven years in dogs. In cats, it takes about eight months to mature into adult worms that live from two to three years.

Microfilariae cannot mature into adult heartworms without first passing through a mosquito.

The reason you shouldn't give the preventative after missing for so many weeks is they can get very sick if there is a heartworm growing already.

Better yet? Move to Alaska, we don't have heartworm-carrying mosquites, just plenty of the normal ones. *LOL*

PS: In the dark ages when I worked for a vet clinic, I saw first-hand many a dog's heart who had died from heartworms. Since you are averse to seeing worms, let me just say it was a horrible sight, like something out of a bad horror film.

Thanks, Maryjo! I knew it's been too long to give them the heartworm pill without getting tested. I was missing the mosquito link. It's been in the 50's here so I don't think we have any mosquito issues. But I'll call the vet and get their take. Chester is due for another re-check next week anyway. Thanks again!

Wow, I had no idea about needing to retest after missing for awhile! I've missed for months and didn't think much of it, since its been cold for so long. I guess I'll have to have them tested next time we go to the vet.

lawpug wrote: I've missed for months and didn't think much of it, since its been cold for so long. I guess I'll have to have them tested next time we go to the vet.

There are some people who do not give HW preventative in the winter months in this area. We use Interceptor & give it year round because it also protects against whipworms & other parasites that they can contract at any time. As far as retesting now goes, heartworms takes six months to mature so it probably wouldn't do much good to test now. I would call your vet to see what they recommend, though.

I am sure they are fine. I do not give it from Nov till about March and unless we do blood work for something else, I do not re-test when I start. Mosquitos aren't really much of an issue there and they are not outside dogs. It won't hurt to give the heartworm meds, after all, if we get a rescue with a mild case and they are older, sometimes the meds are enough to treat the heartworms. Also like someone mentioned the test are often of no use as unless it's been 6 mos and it's bad case they usually test negative. With bad cases the vet can listen to the heart and tell if there may be heatworms. You can see problems breathing in bad cases too.

Great question and great info! thanks for asking it..because I too am unfamiliar with it. I have not had to deal with it (*knock on wood*) and hope to never, but i think it's good to educate youself on signs and symptoms.

OK, here is one of those things that make you say hmmmmmm...

I know they say if you miss a month you should retest...but for low grade heartworm, they treat with Heartguard! I think it is more for the guarantee. If you have your animal consistently on the medication and have the tests that show they are HW negative, the durg company will supposedly pay for the heartworm treatment should your dog still get HW while on the meds.

Pugsavers wrote:OK, here is one of those things that make you say hmmmmmm...

I know they say if you miss a month you should retest...but for low grade heartworm, they treat with Heartguard! I think it is more for the guarantee. If you have your animal consistently on the medication and have the tests that show they are HW negative, the durg company will supposedly pay for the heartworm treatment should your dog still get HW while on the meds.

Yeah, that's where it gets confusing. My vet told me once years and years ago that even though the package says you are supposed to give the pill once a month, you can go as long as 8 weeks between pills (I think he was going to say longer but he stopped himself at 8 weeks). This is the longest they've ever gone without the pill. And I will call my vet, but I know what they're going to say -- get them in for the test because it's the safest answer, and the one that generates a bunch of money for blood tests on 3 dogs.

As others have mentioned, you should be safe to go ahead and give the pill. Even if a dog is infected, it takes a bit for the worms to turn into adult worms. Even if for some strange reason the dog became infected, the monthly dose should easily kill the immature worms. I give Interceptor all year round since it protects against some of the other parasites. My old vet wanted to test yearly, but my new vet here says if I give it yearly then he feels safe testing every two years.