Heartworm preventative questions

[Saeleofu]

It's not that you have to test every time you buy more. You have to test once a year (depending on the vet), which you're doing.

Exactly The test is good for a year as long as you stay on preventative.

I use HeartGuard, which my dog loves, that I get on line. The last time i bought it, I found a site in New Zealand that shipped it to me without a script.

I would advise against getting stuff from out of country. Sure, people do it, but I personally wouldn't. At our clinic we'll actually match the prices of the online pharmacies as long as people bring in proof (like a printout of the prices).

 

[GlassOnion]

Ok I didn't follow the whole thread, just poked in at various points through the pages to see what was being said.

To answer the initial question: no preventatives don't (readily) kill the adults. They can though (depends on which you use). If you give a heartworm infested dog preventative and it does kill an adult, the adult dies, breaks up, and gets lodged in pulmonary capillaries. Your dog then basically has a heart attack, suffocates, and then dies (which is the common end result of the former two conditions). This is generally only an issue with large numbers dying at once, but that's exactly the problem. A controlled dose of an arsenic compound can more or less control how many die at once. A shotgun blast of preventative could just kill everything all at once. You get the job done, but there's a lot of friendly fire too.

This is the primary reason why the vet won't sell you heartworm preventative past a year without having a test. It's for the good of the animal, and the vet (you could sue the vet if your dog died from meds they sold you without them following 'protocol').


EDIT: Oh forgot, yah you're getting boned on the cost of the test. That IS a money grab. We charge $30 for the test and still get about $10 of profit off it. I'd find another vet.

Because of the lifecycle of the heartworm explained above plus the way the "prevenative" works. The "prevenative" only kills larvae. It kills the larvae that is in the dogs body the day the "prevenative" is administered. It doesn't hang around in the body for a month until the next one is given. When the next prevenative is administered, it kills all the larvae that have entered the body since the previous dose was given. If you give the "prevenative" no further appart than 45 days, all the larvae will die before becoming adult heartworms.

Problem with this is that the preventative sometimes doesn't kill every single microfilarid. Also the preventative only kills two stages of the microfilarid. There's three in the dog (well technically 4 but only 3 that cause issues). To make it simpler, there's L1, L3, L4, L5, and then the adult. L1 is what the mosquito picks up, L3 is what infects the dog. L4 and L5 are what's primarily moving through the dog. Preventatives kill L3 and parts of L4 (this is where it gets dicey). It doesn't always kill all L4 though, and won't work on L5 at all.

Personally, I think you've just gotten lucky up to this point and you're doing you and your dog a disservice. No offense intended, just how I see it. But I"m by no means an expert on this stuff. The internet isn't either, though.

 

[noludoru]

Personally, I think you've just gotten lucky up to this point and you're doing you and your dog a disservice. No offense intended, just how I see it. But I"m by no means an expert on this stuff. The internet isn't either, though.

He's been tested regularly up until I want to say a year or a year and a half ago - the last time I bought preventative.

And again, I just want to add for the seven-thousandth time, I don't have an issue with the actual test, I think it's a good idea. It was the price that made me freak out and wonder if the testing was actually necessary on a yearly basis, and if it could be skipped for another year. As I stated previously in the thread I'm going to be going somewhere that doesn't charge $100 for a test this spring.

ETA: I just realized I had forgotten to include that bit of info in my OP. We switched vets about a year ago, and a little less than a year and a half ago he had a heartworm test from the previous vet and I bought heartworm preventative. The current vet has been pushing the test since I came to them, even though he'd had it fairly recently and was on medication when I came to them.

 

[Jynx]

I also think 100 is excessive for testing for HW...I just paid 55$ for a Snap 4,,which is HW, Lyme, Equii erhlichia and canine erhlichia.

I test once a year, and keep them on a monthly prevantative from april thru november.

 

[GlassOnion]

Personally, I think you've just gotten lucky up to this point and you're doing you and your dog a disservice. No offense intended, just how I see it. But I"m by no means an expert on this stuff. The internet isn't either, though.

He's been tested regularly up until I want to say a year or a year and a half ago - the last time I bought preventative.

This wasn't directed to you Nolu. Everything I had to say to you was above the quote.

 

[noludoru]

This wasn't directed to you Nolu. Everything I had to say to you was above the quote.

Ohh okay. I misread. Sorry, GO.

 

[Saeleofu]

I just checked the price list today, and the snap test costs $31.65

Take your business elsewhere and use the remianing $70 to buy preventative

I did hear of one place that charges $101 for a heartworm test, but they send a tech out to your house to draw the blood. Somewhere in Florida if I remember right.

 

[RawFedDogs]

Problem with this is that the preventative sometimes doesn't kill every single microfilarid. Also the preventative only kills two stages of the microfilarid. There's three in the dog (well technically 4 but only 3 that cause issues). To make it simpler, there's L1, L3, L4, L5, and then the adult. L1 is what the mosquito picks up, L3 is what infects the dog. L4 and L5 are what's primarily moving through the dog. Preventatives kill L3 and parts of L4 (this is where it gets dicey). It doesn't always kill all L4 though, and won't work on L5 at all.

Yes, I agree 100% with this paragraph. The larvae is L3 when it goes into the dog. It remains an L3 for 45 days. The "prevenative" will kill L3 larvae that is in the dog at the time he is treated. We don't disagree with this. I don't see what part you are disagreeing with except maybe the part where I am not treating during the parts of the year that there are no mosquitoes. No mosquitoes means no L3's.

The reason the manufacturers suggest once a month instead of 45 days is because many people would have problems keeping up with 45 days. I use 42 days (6 weeks) and mark it on my calendar. It's easier for me to keep up with if I always do it on the same day of the week and I have 3 extra days each cycle incase I forget one day.

Personally, I think you've just gotten lucky up to this point and you're doing you and your dog a disservice. No offense intended, just how I see it. But I"m by no means an expert on this stuff. The internet isn't either, though.

I don't see it that way. I see it as using logic to minimize the number of doses of poison I have to give my dogs in a year. In my case, I give them 4 doses a year, less than half what most people give and I think they are protected very well.

ETA: If you live in a dofferent part of the country or world, your mosquito season would probably differ from mine and you would give either more or less doses.

 

[GlassOnion]

The larvae is L3 when it goes into the dog. It remains an L3 for 45 days.

You may consider double checking your source. The Merck vet manual says 2 - 3 days for the L3 to molt to L4, Heartworm Society says that it can occur as early as day 3, as late as day 12, my undergrad parasitology notes say about two weeks, and the parasitology classes in vet school (A&M and LSU are the only ones I'm familiar with, though you'd expect the information to be standard) are told 3 - 17 days. Your 45 days doesn't sound accurate and the only supporting evidence I could find for that figure was on some holistic vet website which didn't even cite where the information came form, so no guarantee it's legit.

It should be noted that the length of L4 is about 45 days, but again, preventative doesn't kill all L4.

 

[Dekka]

Here's what I do. I don't give prevenative during the winter when there are no mosquitoes. BTW: Mosquitoes are how dogs get heartworm. Also, the heartworm larvae enter the dog's body through a mosquito bite. It remains a larvae for 45 days before becoming an adult heartworm. Sooo ... I wait until about 42 days (6 weeks) after mosquitoes appear around here. They usually appear around the middle of April.

Not that I care much about what you do or not do... But am curious where you live that there are ZERO mosquitos ever in winter. I live in ontario and find the odd one in my house in the winter.

Interesting fact. Westnile is transmitted soley by mosquito vectors. Horses are showing up in the dead of winter in Ontario with the onset. If there can be the odd mosquito in a barn in Ontario in January, how are you soooo sure your dog won't find any in the winter where ever you are?

I live in a very low risk area, so am not overly worried about hw. But to think that your schedule is preventing it seems kind of far fetched.

 

[Bailey08]

This is unrelated to the OP, but I thought I'd put it out there for people buying HW treatment outside of a vet's office.

'Gray Markets' in Veterinary Medicine | PetMD

Maybe it's hype, and/or the chance of getting "bad" meds is tiny, but I do buy Bailey's HW medication from the vet. My vets also see us a lot and often don't charge me for super-short "can you take a look at this?" visits, so I feel okay about supporting them by purchasing Heartgard and Frontline there.

Not preaching, just sharing information.

 

[Saintgirl]

Just a question. I thought that the temperature had to remain above 14 C or 57 F for the mosquito to be able to transmit heartworm, and this is the reason that the winter months are not a huge risk factor in more northern climates? I was always under this impression, but perhaps I am wrong.

 

[elegy]

you're correct saintgirl, and it has to stay above that temperature for a number of weeks.

 

[GlassOnion]

Only two weeks, not any great length of time. And actually it's really only the end stage molting (L2 -> L3) that needs that temperature, so it's really not even two weeks long. That's just the amount of time the L1 -> L3 takes in the mosquito. It's the molting that requires a decent temperature.

And mosquitoes can still live indoors. However yes, the chances of contracting heartworm are greatly reduced in the winter months (excepting the southern climates).

 

[RawFedDogs]

You may consider double checking your source. The Merck vet manual says 2 - 3 days for the L3 to molt to L4, Heartworm Society says that it can occur as early as day 3, as late as day 12, my undergrad parasitology notes say about two weeks, and the parasitology classes in vet school (A&M and LSU are the only ones I'm familiar with, though you'd expect the information to be standard) are told 3 - 17 days.

If any of those were true, that would be the time between heartworm pills. Since the manufacturers state 30 days between pills I suggest that is the minimum time, however I have also read that they suggest 30 days because it's easier to remember to give the pills on the same day of them month. 45 days between pills is safe.

 

[RawFedDogs]

Not that I care much about what you do or not do... But am curious where you live that there are ZERO mosquitos ever in winter.

I live in west Georgia and have a 10 acre swamp on my property. In the 6 1/2 years I've lived here I have never seen a mosquito after around first of November and not again until early to mid may.

Interesting fact. Westnile is transmitted soley by mosquito vectors. Horses are showing up in the dead of winter in Ontario with the onset. If there can be the odd mosquito in a barn in Ontario in January, how are you soooo sure your dog won't find any in the winter where ever you are?

Or maybe the disease lays dormant in the horse for a few months? Don't know. I just know I don't see them and I have zillions during the warm months.

I live in a very low risk area, so am not overly worried about hw. But to think that your schedule is preventing it seems kind of far fetched.

Say what you want. It's worked for me for over 10 years and I live in a highly infested mosquito area. I like not putting poison in my dogs 12 times a year.

 

[Dekka]

Oh I live in a very high mosquito area (but not high hw area) and I don't poison my dogs even as often as you. But I do acknowledge there is a risk. I feel that poisoning my dogs is a bigger risk, but that is not the point.

Most people have dogs their whole lives around here and their dogs never get heart worm. But that doesn't mean that doing nothing is the best plan, just that when playing the odds people get lucky.

No its not dormant. And I have seen mosquitoes in barns in the winter. Not many, but it doesn't take many.

So you have been lucky so far. I hope your luck continues.

 

[bubbatd]

I paid $28.40 for the yearly test . I take my chances during cold weather .

 

[RawFedDogs]

I just took my Thor to the vet today for his annual heartworm check. Total charge was $25. There was no office visit charge.

 

[GlassOnion]

Since the manufacturers state 30 days between pills I suggest that is the minimum time, however I have also read that they suggest 30 days because it's easier to remember to give the pills on the same day of them month. 45 days between pills is safe.

Again, parts of L4 are susceptible to treatment. L3 duration + time that the L4 is susceptible to meds = medication time.

If any of those were true, that would be the time between heartworm pills.

And you're seriously saying that the whole veterinary community is wrong?