Look at the life cycle yourself. The microfilaria have to live inside the mosquito for 10-14 days and if at ANY point the temperature drops below 57*(F) then the microfilaria die. What I do is keep an eye on the weather. If the temp stays above 57* for 2 weeks then 3 months later I give 1 dose of Heartguard. A single dose will wipe out any infection that has occurred in the previous 3 months, from what I've come to understand.

http://www.heartwormsociety.org/veterinary-resources/canine-guidelines.html#2

The susceptible mosquito becomes infected when taking a blood meal from a microfilaremic host. The microfilariae develop to the third stage in the mosquito’s malpighian tubules and then migrate via the body cavity to the head and mouthparts of the mosquito where they become infective. The time required for the development of microfilariae to the infective stage in the mosquito is temperature dependent. At 27°C and 80% relative humidity, development takes about 10 to 14 days.

When I do give Heartguard, I smash it up really well first.

 

I just gave my dog his first heartworm pill the beginning of this month.

I also use the safe heart dose.http://www.fda.gov/AnimalVeterinary...lVeterinary/Products/ApprovedAnimalDrugProducts/FOIADrugSummaries/ucm054862.htm

Basically the safe heart was interceptor given at a lower dose. Since interceptor was discontinued I use sentinel. I just give the dose for dogs up to 10lbs. The only problem is it doesn't protect against other worms. I don't think it's something that I should have to worry about every month anyways. There is just no need to deworm a dog every month which is basically what giving those all-in-one products is doing.

 

Whether or not it's a significant risk totally depends on where you live.

I have fostered several HW+ dogs and seen half a dozen die of serious complications of untreated heartworm disease. My best friend lost a dog to HW disease while using 12 month prevention. For real. Dog couldn't survive the "slow kill" method of treatment that her vet suggested given the dogs age and other issues.

The disease is very real and very serious. Nice snappy headline, but man, heartworm sucks.

 

I think the article is much less applicable if you're in the South. Here in Ontario (Canada) there has been an increase in HW incidence but the numbers are still very low. I want to do a lot more research, we're covered for the rest of this year since HW season is short. I'm considering doing something different next summer though. My vet bills this year were *insane* - seemingly without very good cause. I want to reign it in next year but of course not compromise too much or put him in danger.

 

FYI-- I live in MN.

 

One of the rescues I help out with crunched their numbers a few years back and found out that 80% of dogs over one year old that come into their rescue are HW+. Luckily, the majority have worm loads that make the "slow kill" method possible, so that is primarily what they do. Keep in mind we have pretty decent winters and live in a climate where a person can get by on seasonal dosing. In southern states many rescues hit the 100% mark.

You have to keep in mind that for those 18-24 months the worms are STILL causing damage, so if there is significant damage already present it will continue to worsen. If the dog has other complicating conditions many times they can't physically last that long with heavy worm loads.

You also have to adhere to a measure of exercise restriction for the entire length of treatment, versus only for a couple months for the "fast kill" method. Imagine trying to keep a young super energetic dog relatively quiet for years. HW+ status also leaves the dog more susceptible to other illnesses. So while the dog may be okay with the heart worms, you often wind up seeing more frequent and serious respiratory issues.

Emmett was positive when he was dumped. Weighing all the pros and cons we decided on the "fast kill" method, but he will always have a sporadic cough, not be able to handle the heat as well as he should and need to be watched in is physical exertion because his respiratory system can't handle it. No he didn't drop dead the minute he was infected, nor even the first year, but it is still a serious disease and a serious risk in most of the country.

 

It is a serious problem here and every time we take a new rescue dog into the vet for a first check up and heartworm test, everyone just crosses their fingers and prays. Basically, if a dog isn't on prevention (it IS prevention in the sense of preventing the development of adult heartworms that cause the problems), there is a high chance of being HW+
It seems most rescues go for the fast-kill method while the dog is in foster in order to limit continuing strain on the dog and to be able to adopt out a HW Neg dog.
I would hazard an unscientific guess that well over 50% of the adult dogs that come in as strays or neglect cases (as opposed to cases like owner surrenders due to owner's housing or health etc where the owner was caring for the dog properly) are HW+

You don't HAVE to use the branded pills/topical, plenty of people do use ivermectin from the farm store at a very cheap price, but I would say that you do HAVE to use something around here. Last winter we had mosquitoes popping up all winter on the odd warm weeks and just not enough deep freezes to knock them out completely so year-round prevention is recommended.

 

Well said. Here in FL, we have mosquitoes year round. Where I am (north FL, close to the coast), we only have a total of about 40 days without mosquitoes. It's a very real, very dangerous risk here. I keep my girl on year round prevention.

 

It sounds like the same kind of stuff I hear from people who are against immunizations for kids.

 

Except the claims here do seem to be rooted in science (I haven't verified everything but nothing pops out as outright quackery). He's not suggesting anything comparable to the anti-immunization crowd's autism claims.

I am very much for immunization for kids. Luckily in Canada our healthcare is socialized so we don't need to consider cost when it come to health care - its not the same equation for dogs as much as I wish it were.

I have more research to do, just thought I'd run it by people here to see if anything pops out as outright wrong or stupid.

EDIT: One thing that I do notice is that my vet told me using HW preventative if he's heartworm positive is really dangerous. Which is why I can only get it on prescription and why they insist on an examination and a blood test before prescription - making just HW a $200 affair. But it looks like the treatment for heartworm actually starts with HW prevention - so why do they do that? Did the vet lie or is there a good reason?

 

I don't think the article is really about whether or not you need to use heartworm prevention but how often. If it takes 3 months for the larva to develop then if you give the prevention every 2-3 months the dog should still be covered. At least that way you're only giving 6 doses at the most instead of 12.

If you're in an area with cold winters then you could give the last does in November and start again whenever the weather rises above 57 degrees for a period of about 2 weaks. It doesn't really matter if the mosquitoes are around in the winter because either way the heartworm parasite can't survive inside the mosquitoes in temps below 57 degrees. They die, even if the mosquitoes doesn't.

 

ok I have a question.. where I live I don't have to worry about heartworm, lyme disease, flea's, nothing. because of this my dogs have never been on any kind of prevention. now in a couple weeks I am travelling with 4 of my dogs, I am going to be backpacking and staying lakeside for a week in an area that has ALL of those things and bad. the vet gave me Revolution with instructions to apply it shortly before we leave home. I am now confused about it not PREVENTING heartworm..its that still right when they are never going to get another dose of anything ever? I don't want to apply it AFTER, then I wouldn't have the flea/tick prevention...

 

I think what the article means is that HW "prevention" is actually HW treatment. That the only way to "prevent" HW is to kill the nematodes/larval worms before they get a chance to develop but after they're in the dog. So Revolution will prevent HW when applied before the trip. I'm using Revolution too and both it and my vet said that I would be covered for the Summer for HW, fleas, ticks etc. That said, we are dealing with a bit of a flea problem so that aspect of it might not work perfectly.

 

I do think that Heartgard has a real scam going, because they place less than one drop of ivermectin on a chewy treat and then sell it for $7 . If they charged something like $2-$3 I wouldn't think it was so awful, but wow, that's some markup. And then the vet insists on a test, so that a LOT of people feel like they can't afford heartworm prevention so they skip it entirely :/. If they knew the lower-cost alternatives it would be a lot better for everybody. And trying to convince people that live in colder areas to give Heartgard all year long.

Other than that, no, I don't think heartworm prevention is a scam. I've known several farm dogs who died of heartworm (or my best guess, because of course they didn't get a diagnosis. But coughing and lethargy were the symptoms).

I use Ivomec.

 

I use Ivomec.

That looks promising. Is there any worry about using it after a period off the drug? Up north mosquitoes aren't a year-round problem so I only do preventative in the summer. The vet said that a blood test was absolutely necessary before taking heartguard because if the dog is infected its really dangerous. Is there any truth to that?

Heartworm test at one of my vets runs about $25 (maybe less when combined with the annual rabies and exam) and the generic of Heartguard around $3-5 per dose depending on dog weight. Of course that is more than Ivomec, but for the ease of giving the dose and the "idiot proof' dosing, $5 a month is really minimal in the grand scheme of things for owning a dog for most people.

I like that most of the sites selling the HW prevention notes that the dose kills the parasites acquired previously to the dose rather than preventing something upcoming.

At my vet the exam fee is $75, blood test $45 and heartguard somewhere in the neighbourhood of $50 for the summer doses. If I ask for a prescription and buy Heartguard elsewhere to save a bit they tack on a $25 prescription fee. About $200 minimum. This is the same vet that cost over $400 to get a prescription of Clomicalm because she insisted I get a consult from an e-vet neurologist before prescribing anything. I will be getting a new vet, but in any event I don't make much and like to save money where I can. If I can get a cheaper alternative and still have HW prevention, why not?

This would be for next year so there is lots of time to sort out the best/safest strategy.

Found something helpful...

You should have the dog tested for heartworms first because once you start treating, the test won't work anymore. Ivermectin will not kill adult heartworms, although there is some evidence that it makes them sterile (can't breed any more so your dog is not a pool for infection) and that it may shorten their lives, usually about 2 years if untreated. So if your dog has heartworms and you start treating him without testing first, you won�t be able to tell later if he needs treatment for adult heartworms. It won�t show up on the test anymore.

Ah, but then....

Our vets ask if the dog is receiving ivermectin, and if they are and we still want to do a test for heartworm, there is a different test available that works.

 

We had to treat our HW+ Lab when I was a kid. She wasn't expected to live through the treatment and it was really rough for several weeks. Don't ever want to have to put another dog through that. I live in FL and the mosquitoes will haul you off here. I keep my dog on HW meds.

 

Heartworm test at one of my vets runs about $25 (maybe less when combined with the annual rabies and exam) and the generic of Heartguard around $3-5 per dose depending on dog weight. Of course that is more than Ivomec, but for the ease of giving the dose and the "idiot proof' dosing, $5 a month is really minimal in the grand scheme of things for owning a dog for most people.

I like that most of the sites selling the HW prevention notes that the dose kills the parasites acquired previously to the dose rather than preventing something upcoming.

 

In my hometown in Texas EVERYONE uses heartworm prevention. The mosquitoes are so awful in South Texas that you they hire trucks to go around every night to kill the mosquitos in the summer time. Sometimes the winters aren't that cold either, so you might have mosquitoes all year round.

However up here in the northwest I don't know anyone who uses heartworm prevention. Mosquitoes aren't really big up here and I don't worry much about it.

If I ever travel with Ammy back home to Texas though I will put her on heartworm before we go.

 

Well the three months thing is incredibly misleading. Heartworm preventatives are best at killing L3 and L4 stages but really inconsistent at killing L5. You could not pay me all the money in the world to give heartworm preventative every 3 months. There is a huge variation in how fast the individual larvae mature through their various stages and hitting L5 before 90 days is absolutely possible. Honestly if I lived down south, I would probably give preventative every 2 weeks just because the sheer exposure virtually guarantees some "early bloomers."

And even up here, where it is "cold," there are plenty cases every year, I wouldn't call it "pretty rare." I wish I could go a single year without seeing a case. Incidence depends more on distribution and prevalence of the mosquito vectors than necessarily the climate - some areas without the proper mosquito species don't give heartworm preventative at all.

Second of all, heartworm preventatives prevent heartworm disease; that is, an infection with mature worms in the heart. No one claims it prevents infection with microfilariae.

Third of all... heartworm treatment easy LOL.

Fourth of all... even if the outdoor temperature drops below 57 degrees, our houses (and under the siding or porch or all the other nooks and crannies) often have microenvironments that remain at a higher temperature.


I never understand why people balk at giving monthly heartworm preventatives. People spend more on a couple of lattes than they do on their monthly pill, and even if it isn't about the money why gamble? The drugs are very safe and are eliminated from the body quickly. Maybe people have to see a dog get treated for heartworm before they take it seriously? I honestly don't get it.

 

I never understand why people balk at giving monthly heartworm preventatives. People spend more on a couple of lattes than they do on their monthly pill, and even if it isn't about the money why gamble? The drugs are very safe and are eliminated from the body quickly. Maybe people have to see a dog get treated for heartworm before they take it seriously? I honestly don't get it.

Maybe you should try paying over 6k in vet bills to treat acute liver disease so you can understand why some people are scared shitless about giving their dog poison on a monthly basis. Even if it is supposedly "safe" poison.

 

We are living in the tropics, so the temperature never drops below 57. I give my babies Heart-Guard every months, not taking any chances. Faith was infected with heartworms before we adopted here. Rather not have that happening again.


We are run over by mosquitoes during summer and have them pretty much year round. I have to give Jing Jing a mosquito prevention designed for horses or she will be covered in hundreds of bites.

 

Thanks for your post Sass! I have a lot more reading and more than a few months to do it in, before making any decisions.

 

I never bought heart worm pills,it normally gets under 60 degrees at night,even in the hottest months of summer. I haven't been bitten by a mosquito yet this year. In winter it can get as low as 15 degrees F at night. I no longer buy lattes and rarely shop for myself as well,my money does tend to go towards animals.

 

Yea, like I said, some areas of the country don't give preventative at all, they just don't have the mosquito populations.

 

I still give my dog his heartworm but I'm just trying to get you to understand that some people do have a reason to care. It's not just about saving money or whatever.

I'm literally so paranoid about giving it to him that for a full week I give him spirulina, SAMe, and milk thistle. I consistently check his eyes, his gums, his stool, his urine. I mean I seriously turn into a nutcase because I'm so scared that it will harm his liver and he won't get better this time.

So yeah, if I can find a way to give him less poison, regardless of how safe it might be, then I would be thrilled.

 

People care because they are ignorant about the risks of everything else.

 

It is a serious problem here like Shell has said. At my clinic we diagnose HW+ dogs almost daily. This last week alone (from Monday until today) we have diagnosed 16 cases at my hospital alone. People have different reactions to being told their dogs are positive. Many people find out their dog is positive and they want to euthanize. Some take them to a rescue and turn them over (most of the time without saying they have HW's). Some leave it alone and let nature take its course (They say they will be back and never come). And some choose to treat. When the rescue brings their dogs in we send up a silent prayer that they will be okay and test negative.

We are in the progress of 6 treatments right now, all in different stages of treatment. At my clinic I am the main person in charge of these poor dogs while they are with us. Its heartbreaking. Some do very well with the treatments. Others however...do not take well to it. They get sick and weak, their gums pale, and they shake. I sit with them and comfort them as much as I can. I give SubQ fluids (and sometimes other things the drs want them to get) and I wait it out. Eventually the symptoms will pass (most of the time) and they will be able to go home until the next treatment. I hate watching these poor animals go through this. The treatment is anything but easy.

My pups are on HG+ year round. They are tested every year. You can never be to safe when it comes to the ones you love. I couldn't bare to see one my dog have to go through this. Like Sassafras said I have never seen a dog with severe reactions to HWP. I have seen horrible reactions to the treatments.

 

I had to treat one of my dogs for heartworm....she came to me with it. And there was no way to know. She was from a breeder, only 7 months old. There would be no reason to even SUSPECT she had heartworm. When she turned a year old, we ran the annual test....and she came up positive. I had her tested again, and they tested the blood twice.

Positive.

It was an absolutely HORRIBLE experience. I was actually going to opt to do the slow kill method until I found out there was a doxycycline shortage. We ended up doing immiticide. It was nerve wracking keeping her lightly exercised. She got the all clear in July, and for the first time in 2-3 months, she got to really RUN like a puppy should. And while she was running, I was still terrified that she was just going to drop dead in front of me.

All of my dogs get Ivomec every month, and the puppy came to me on Ivomec (she came from Georgia). I hope I don't ever have to go through HW treatment again

 

How do you dose the Ivomec? Also, a quick search showed an injection method. How do you give it? Orally?

 

Yup, just give it orally. That said, it's really not cost effective unless you have multiple dogs.

 

I have three.

 

I can tell you that if you live in the gulf states, heartworms are the REAL DEAL. Fail to use a preventative, your dog will get heartworms. Sooner or later.

I am old enough that I go back pre heartgard, pre flarabits, to some gooey syrupy nasty stuff you squirted on your dogs food every day. Many dogs would not eat it.

Before Flarabits, we lost dogs to heartworms. Dogs die down here from heartworms all the time.

And down here it is a 12 month a year thing.