Heartworm Prevention

While preparing this post about heartworm prevention for dogs, I came across many controversial issues during my research. While I myself do give my pups Heartgard monthly, I am now beginning to get a little concerned. Of all the supplements, vitamins and preventatives I use, Heartgard is the only Vet prescribed preventative used; everything else I use is all natural and non-chemical. (essential oils, vitamins, herbs)

We all know that our Veterinarians prescribe heartworm preventative for a reason. Heartworm is a serious and potentially fatal disease caused by foot-long worms that live in the heart, lungs and associated blood vessels of affected dogs.

Dogs are considered a natural host for heartworms, meaning that heartworms living inside dogs mature into adults, mate and produce offspring. If untreated, numbers can increase and dogs have been known to harbor several hundred worms in their bodies. Heartworm disease causes lasting damage to the heart, lungs and arteries, and can affect the dog’s health and quality of life long after the parasites are gone. For this reason, Veterinarians believe prevention is by far the best option, and treatment, when needed, should be administered as early in the course of the disease as possible.

While heartworm preventives are highly effective, they do have risks; no drug is entirely harmless. Heartworm preventives are chemical insecticides with the potential for short- and long-term side effects that can damage your pet’s health. Adverse effects of heartworm preventions include reactions such as vomiting, loss of appetite, shock, tremors, coma, seizures, and respiratory failure.While drug reactions can happen in any pet, some breeds are particularly sensitive to certain drugs. If you are concerned, your Veterinarian can actually run a test and find out. A quick blood sample or cheek swab can be taken to test for the presence of the MDR1 mutation which determines whether your dog may have increased sensitivity to these drugs. That said, it’s important to keep in mind that any pet can have a reaction to any medication at any time. 

In addition to concerns about the toxicity of these insecticides, there is also evidence growing of heartworm resistance to preventives. A “Superbug” resistance is typically the result of overuse of certain drugs, like antibiotics.

There are a number of heartworm preventatives advertised as being natural alternatives available on the market. Most of them are basically combination of liquid extracts, herbs, and, essential oils, with some diatomaceous earth and black walnut. While some of these ingredients can help to “repel” pests their effectiveness to actually prevent infection is, doubtful.

The latest rationale for recommending year-round heartworm preventives to all pets everywhere is that “… heartworm disease has been diagnosed in all 50 states, and risk factors are impossible to predict.” While it may be true that at least 1 dog in all 50 states has been affected, it does not mean heartworm disease is a significant threat in every state, or even in most states.

If you live in an area of the U.S. where mosquitoes are common and you know your dog’s risk of exposure is significant, here are some recommendations for protecting your furry family member:

With guidance from your Veterinarian try using natural preventives like heartworm nosodes rather than chemicals.

Since heartworms live in your pet’s bloodstream, natural GI (gastrointestinal) dewormers, such as diatomaceous earth, and anti-parasitic herbs (e.g., wormwood, pumpkin seed, black walnut tinctures) are NOT effective at killing larvae in the bloodstream.

Focus on keeping your dog’s immune system in tip-top shape by feeding an appropriate diet that helps bolster natural defenses.

If your dog’s kidneys and liver are healthy, try using a chemical preventive at the lowest effective dosage. Give the treatment at six-week intervals rather than every four weeks, for the minimum number of months required during mosquito season.

Avoid all-in-one chemical products that claim to get rid of multiple types of worms and external parasites as well. The goal is to use the least amount of chemical necessary that successfully treats heartworm. Adding other chemicals just increases the toxic load your dog’s body must contend with. Also it is recommended to avoid giving your pet a chemical flea/tick preventive during the same week.

Always insist on a heartworm test before beginning any preventive treatment. If your pup spends a lot of time outdoors it is recommended to test for heartworm every six months. The reason is because parasites are becoming resistant to heartworm, flea and tick chemicals. The sooner an infection is identified in your pup the sooner treatment can begin with fewer long-term side effects. 

Obviously, there’s tons of information out there on both sides of the heartworm prevention issue. I have shared what I think is important for all of us to know. I also recommend you do your own research, and if you have concerns or your pet has had any kind of reaction to the preventative you are giving, sit down and talk to your Veterinarian. Don’t be afraid to voice your concerns!

So you may be asking what does this author think now? If I had a dog that had a specific issue or reaction I may try other holistic methods, but based on my research and weighing the pros and cons, I honestly believe your dog is more likely to contract and even die from heartworms than to have a reaction to the prevention. 

Sources and further reading: