Some vets tell dog owners that heartworm medicine is too dangerous to use.
Does that surprise you?
Holistic veterinarian Glen Dupree didn’t want his patients taking heartworm medicine. Dr Dupree found that a strong immune system was enough to protect his dogs from heartworm. And he also knew that giving dogs neurotoxic drugs every month would harm that immune system.
“I assume my dogs have heartworms,” said Dr Dupree. “But there’s a big difference between heartworms and heartworm disease.”
And that difference is a fully functioning immune system.
There are many holistic vets who don’t recommend using heartworm medicine but the pro-health approach to parasite prevention isn’t all that popular … yet.
Here’s why holistic vets avoid heartworm medicine for dogs …
Heartworm Prevention For Dogs: Thinking Outside The Box
In fact, the immune system is well equipped to deal with parasites.
A well-tuned immune system is the difference between a few heartworms .. and a large heartworm load that affects your dog’s health.
A Closer Look At Heartworm
The vets at the American Heartworm Society (AHS) agree with me:
“Single-sex heartworm infections, host immune responses affecting the presence of circulating microfilariae and the administration of heartworm preventives can be factors which produce occult infections in dogs.”
An occult heartworm infection means there’s an infection of some sort but the microfilariae … or the heartworm offspring, aren’t circulating in the blood. All of the heartworms might be of the same sex … or the dog might be on preventives. So then those little guys can’t reproduce and cause much of an issue.
While the vets and researchers may call this an occult infection … it’s really just a functioning immune system.
Look at that quote again. If you go to the AHS, it’s easy to miss it. But there it is, nonetheless, shoved into a little corner and never mentioned again:
“Host immune responses affect the presence of circulating microfilariae.“
In a nutshell, this means that dogs with functional immune systems aren’t good hosts for heartworms and other parasites. The mosquito microfilariae or larvae are killed by the immune system before they develop into adult heartworms.
That’s the good news …
The sad part is few dogs these days have a strong immune system. And a big reason for that is over-vaccination.
Your Dog’s Immune System And Heartworm
While vaccines can protect your dog from infectious disease, they come at a cost.
Vaccines contain mercury (yes, even thimerosal-free rabies vaccines can still contain mercury), which is neurotoxic and causes cancer and autoimmune disease. In fact, research labs will give lab animals just a tiny bit of thimerosal to give them autoimmune diseases! (These include allergies, cancer, arthritis, or GI diseases.)
Vaccines also contain aluminum. Aluminum is neurotoxic and can cause degeneration of the brain and nervous system … especially in young dogs. And the scariest part about aluminum is that it increases the toxicity of mercury, so the “safe” levels of mercury in your dog’s vaccines are severely underestimated.
Vaccines also contain MSG as well as formaldehyde … which is one of the most hazardous and highly cancer-causing compounds known.
So … I don’t know about you, but I’d be very reluctant to call any dog who’s been injected with these toxins healthy. Even just once!
As well as having harmful ingredients, vaccines suppress the immune system.
In fact … immunologist HH Fundenberg says if your dog receives just one monovalent vaccine, his cell-mediated immunity will be cut in half … and just two vaccines will lower it by 70%.
Monovalent means the vaccine has a single virus. But most dogs get several at the same time. Here’s what HH Fundenberg says about 3-in-1 vaccines:
“… all triple vaccines markedly impair cell-mediated immunity, which predisposes to recurrent viral infections, especially otitis media, as well as yeast and fungi infections.”
Yet most dogs get 3 to 7 vaccine components at a time. Is it any wonder why dogs … even minimally vaccinated dogs, get heartworm? I hope you’re following me.
We know the immune system is responsible for protecting our dogs from heartworm and other parasites. So why would we purposely expose our dogs to things like vaccines when they destroy that immunity!
Most dogs are vaccinated with too many vaccines … and much too often. It’s no wonder vets worry about heartworm.
But that brings me to …
Why I Don’t Give My Dogs Heartworm Meds
Just as vaccines can damage the immune system, so can your dog’s heartworm meds.
Now I know you’re terrified to even think about not giving your dog heartworm meds. But don’t worry, I’ve got a solution I think you’ll like! Just keep reading.
But you need to know that all drugs carry risk and adverse reactions.
What are those risks?
Actually … I can only guess. Because I don’t think anyone has tested heartworm meds for more than a few weeks. We have absolutely no idea just how toxic they are when given every season for your dog’s whole life.
So the best guess we have is the adverse reactions that occur right after taking heartworm meds. Here they are:
Heartworm Medication Side Effects
HEARTGARD and TriHeartPlus (ivermectin):
Depression/lethargy, vomiting, anorexia, diarrhea, mydriasis, ataxia staggering, convulsions and hypersalivation.
INTERCEPTOR (milbemycin oxime):
Reports the above reactions plus weakness.
SENTINEL (milbemycin oxime):
Reports vomiting, depression/lethargy, pruritus, urticaria, diarrhea, anorexia, skin congestion, ataxia, convulsions, hypersalivation and weakness.
REVOLUTION® (selamectin), Topical Parasiticide For Dogs and Cats:
Pre-approval reactions of vomiting, loose stool or diarrhea with or without blood, anorexia, lethargy, salivation, tachypnea, and muscle tremors. Post-approval experience included the above plus pruritis, urticaria, erythema, ataxia, fever, and rare reports of death and seizures in dogs.
Severe allergic reactions (anaphylaxis): facial swelling, itching, difficulty breathing, collapse; lethargy (sluggishness); not eating or losing interest in food; any change in activity level; seizures; vomiting and/or diarrhea (with and without blood); weight loss; pale gums, increased thirst or urination, weakness, bleeding, bruising; rare instances of death. This product was voluntarily withdrawn from the market in 2004 because of deaths but has been reintroduced.
Here’s the way I look at it. These meds work by poisoning and killing larvae. So if they’re toxic for heartworms, they’re toxic for your dog.
And for my dogs, even a little bit of poison isn’t something I would give them. It weakens their immune system … and makes them more susceptible to all the other diseases out there.
How To Stop Giving Your Dog Heartworm Meds
Now I know you may be reading this and thinking “I’m not going to stop vaccinating my dog and stop giving heartworm meds … you’re crazy, Dana!”
You have every right to think that way. Heartworm is a scary disease that could threaten your dog’s life. And the treatment is costly and really rough on your dog.
But what if I told you it’s possible to protect your dog from heartworm without using those meds?
Here’s some news for you. Heartworm meds don’t prevent heartworm at all … they kill heartworm larvae that are already in your dog.
The only prevention they offer is killing the mosquito larvae before they develop into adult worms. It’s the adults that migrate to your dog’s pulmonary artery and cause heartworm symptoms.
The Difference Between Microfilariae and Larvae
Before I continue, I want to clear up some possible confusion. Anybody who talks about heartworms uses the terms microfilariae and larvae. And frankly, some vets don’t even really understand the difference.
It’s not surprising we’re all confused … because the AHS doesn’t even explain the difference clearly. They say things like …
[by giving heartworm meds] …”you are helping to keep your dog from being a source of heartworm larvae (microfilaria) for mosquitoes to pick up and eventually infect other dogs.”
So that’s a bit misleading. It makes it look like microfilariae and larvae are the same thing. They’re not! They’re both young heartworms. But here’s the difference.
Microfilariae are heartworm babies.
Larvae are the toddlers that grew up from those babies.
So a mosquito gets infected with microfilariae that grow into larvae. Then when the mosquito bites your dog, your dog gets the larvae in his tissue.
How Heartworm Disease Develops In Dogs
I also want to go over the timing of how heartworms develop if your dog gets infected. (This information came from the American Heartworm Society. They also have a very clear chart that does show the process quite well, so I’ve referred to it in the text below).
Breaking down the timing a bit more …
Again … here is the AHS heartworm lifecycle chart. I think the visual image is helpful.
How Heartworm Drugs Work
Heartworm meds work by killing the larvae.
But they’re risky when there are adult heartworms. That’s because they don’t clear microfilariae … and they could cause your dog to have a reaction to the drug. So your vet wants to test before starting the meds each year.
And that’s also why your vet wants you to give your dog heartworm meds every month … so that the larvae don’t develop into adults. But what she likely didn’t tell you is that it takes at least 5 months for those larvae to mature into adult heartworms.
Seems like a lot of unnecessary poisoning of your dog, doesn’t it? Researchers have pointed out that the practice of giving heartworm drugs for 5-7 months is probably more than you need. They suggest that in most places giving the medication during 3 peak summer months is sufficient.
Obviously if you live somewhere with year-round mosquitoes it’s different. In some warm, humid climates your vet will recommend heartworm prevention year-round.
So … now that you understand the timing, here’s how you can replace those dangerous meds with well-timed testing!
Replacing Heartworm Meds With Testing
So we know heartworm meds can kill larvae but shouldn’t be used to treat adult worms.
Note: If your dog develops adult heartworms, your vet may still use the drugs as part of the conventional treatment. But it’s risky because dead or dying microfilariae can cause reactions in your dog. So your vet needs to supervise closely.
We also know it takes at least 5 months for larvae to develop into adult heartworms.
So why are you giving your dog these toxic meds every month when all you have to do is just run a test at the right time?
(Stay with me … I’ll explain in detail). First, I want to tell you about the different ways to test for heartworms.
How Heartworm Tests Work
There are 3 different types of heartworm tests.
The regular test your vet does is an antigen test. Here are the shortcomings of this test.
- It can only identify adult female heartworms. That’s why your vet says it takes heartworms 6 months to show up on testing.
- Heartworm antigen can be in the blood within 5 months. But most dogs won’t show antigen until 7 months after infection.
- These tests also may not pick up a low worm burden. If your dog only has one or two female worms, the test has a 30-40% false negative rate.
- Some dogs won’t show antibody at all due to “antigen-antibody complexes” in the blood.
So that’s why your vet may also do a microfilariae test.
This test will show if there are microfilariae in your dog’s system. And official recommendations have changed. In the past, vets only did it if the antigen test was positive or weak-positive.
The AHS now recommends doing the microfilariae test annually … to avoid false negatives on the antigen test. A positive microfilariae test confirms there are mature heartworms in your dog … and they’re breeding.
Those two are the tests your vet likely knows about. But there’s a little known, third type of test.
DNA Heartworm Test
This is a DNA test using PCR (polymerase chain reaction) technology. It tests for heartworm DNA in your dog’s blood.
The only place I know to get this test is HealthGene in Canada. The test is the D319 Canine Heartworm (Diofilaria immitis) test on this page. HealthGene confirmed to me by phone that it identifies heartworms at all stages … microfilariae, larvae and adult heartworms.
You’ll need your vet’s help, because HealthGene won’t work with you directly. Your vet can order the test kits here. Then she’ll have to send the sample to HealthGene in Canada.
So … which test should you get? And how often?
Which Heartworm Test To Choose For Your Dog
The best choice is the DNA test by HealthGene.
As you’ll remember … when an infected mosquito infects your dog, it transmits larvae. The larvae take 4-5 months to grow into adults. So … if you did the DNA test every 4 months, you’d find out your dog had heartworms a lot sooner than if you waited for annual antigen testing by your vet.
And finding the larvae vs adult heartworms means the infection is much easier to treat. (I’ll talk about positive tests in a minute.)
DNA testing means you’d only need to give heartworm meds if your dog’s DNA test was positive for larvae … instead of every single month.
It’s more hassle to get this test. But it’s doable … you just have to talk your vet into it! It’s worth the effort to avoid the neurotoxic risks of the heartworm meds.
But if that’s too hard (or expensive) … or you just can’t find a vet to help you …
Next best is the regular antigen test your vet does. But you’ll need to do it more often than once a year.
Vets continue to insist there’s no point in testing more often than once a year. That’s because the test won’t be positive until 6 or 7 months after infection. So most vets will test in spring, before prescribing heartworm meds for the next season.
But wouldn’t it be better to know your dog’s positive sooner rather than later? Assuming peak mosquito season where you live is summer months (June through August) … why not test in January or February … then again in late spring? Or about 7-8 months after the start of heartworm season wherever you live.
So if your dog is positive, you can start treating him a few months sooner … before more adults develop.
(The microfilariae test is just a way of confirming accuracy of the antigen test. So if you want to be more confident, you could do it alongside the antigen test.)
What If The Heartworm Test Is Positive?
But what happens if your dog’s test comes back positive? What then?
Again, it depends on which test you do.
If you get a positive DNA test showing your dog just has heartworm larvae, you can treat him with regular heartworm meds.
Your dog should never get adult heartworms if you do this. And you can avoid the dangerous and costly heartworm treatment your vet warns you about.
If you get a positive antigen test (and maybe microfilariae test) … that means your dog has adult heartworms.
Even then, you do still have a choice.
One More Reason To Dump Your Dogs Heartworm Meds
You might have heard that heartworms are becoming resistant to heartworm meds.
That’s absolutely true. And the more we use the drugs, the less effective they become. In the US, more and more dogs each year are getting heartworm while on the meds.
Yet ironically, the AHS responded to these reports by urging pet owners to give heartworm meds year-round. Let’s see … the heartworms are becoming resistant to the drugs … so the solution is to give more drugs? Doesn’t make sense to me!
Why do they think giving heartworm meds more often is the answer? Well, it might have something to do with the companies who fund them …
Their sponsors are names like …
All makers of heartworm drugs! So of course … the people who make money from heartworm meds want you to take them more often.
But that doesn’t mean you have to buy their products. To me, heartworm meds have no place in my dogs’ health care.
It’s ludicrous to feed my dog a small amount of poison every month and think I’ve made him less likely to get sick. Yes, he might have less risk of heartworm, but my dog (and your dog too) statistically has a 50/50 chance of getting cancer.
That’s right … 50/50. So why add to his health risks by giving him toxic drugs?
I think it’s my job to question every drug my vet wants him to take. And in the case of heartworm meds, the answer is a no-brainer.
So in summary, here’s why I don’t give my dogs heartworm meds:
#1 Heartworms are becoming resistant and even dogs on meds are getting them
#2 Heartworm meds contain toxic ingredients that make my dog more likely to get heartworms and other parasites
#3 Heartworm meds can be replaced with regular testing
Perhaps you’ll consider avoiding these drugs too. Your vet may disapprove … but I hope I’ve given you enough information to help you navigate that discussion!