What options do I have in heartworm “prevention?”

Heartworm medications are regulated by the FDA. Legally, your pet’s only protection is with one of the standard veterinary products. These days, those are either monthly chewable or topical products. The problem is that only pharmaceuticals can legally be licensed to treat an illness. Therefore, any of the other options for protecting your dog or cat against heartworms is with supplements. Supplements, under national law, cannot be labeled as treatment for any illness.

A less expensive option for “preventing” heartworm infection in dogs is to use ivermectin. You must be very careful! In fact, one dose is such a minuscule amount of ivermectin that a small bottle of pig dewormer (injectable ivermectin) would last your lifetime, not just the lifetime of your pet. However, because it is very easy to overdose an animal on ivermectin, I highly recommend you have your veterinarian help you calculate the correct dosage of ivermectin. Hopefully your veterinarian will be open to dispensing inexpensive medication safely. Not all veterinarians are in the business to make money selling pharmaceuticals! Oh – and the tiny dose of ivermectin is given orally (by mouth) once every 30-45 days during heartworm season (when temperatures are over 57F for more than 2 weeks in a row).

One other very strong warning: do not give ivermectin to Collie breeds. Collie dogs cannot process ivermectin.

These days, most heartworm “preventatives” are combination medications designed to treat not only heartworm disease, but also intestinal parasite infections. The irony is, unless your pet eats worm infested feces, risk of infections with intestinal parasites should be quite low. This previous statement does assume that the dog or cat in question was fully evaluated as a puppy or kitten and the worm infection associated with infancy was cleared.

These days, there are even some new combination heartworm “preventatives” which are meant to prevent tapeworm infections. The only way a dog or cat, or humans for that matter, gets tapeworms is from eating a flea or uncooked mouse. Prevent fleas, and get your pets to cook their mice!

Silliness aside, those people whose pets are hunters know who they are; if you see tapeworm segments on your pet’s rectum, then it’s time to treat for tapeworms. The majority of pets do not have these exposures in this country. Therefore they do not need to be treated with a strong chemical on a monthly basis to prevent an intestinal infection to which they are not exposed.

Perhaps you’ve noticed I keep putting the word “prevention” in quotations. This is because heartworm “prevention” is not truly prevention. The medication kills the previous 30 to 45 days of exposure to heartworms. When an infected mosquito bites and inserts its heartworm larva laden saliva into the dog or cat, the heartworm lifecycle continues. The pharmaceutical heartworm “preventatives” are treatments, not preventatives.

One thing to consider with heartworm “prevention” is what is your pet’s exposure or risk? If you live near a swamp, the risk is high; if you live in the desert, the risk is quite low. And remember, the lifecycle of heartworms must include a mosquito. If your dog lives next door to a heartworm positive dog, your dog will not get affected by the other dog – has to be a mosquito bite.

Legal disclaimers out of the way, anecdotally, there are people who have used alternative methods to prevent heartworm infection in dogs and cats. I will list some of these, please remember that legally none of these treatments are FDA approved to “prevent” or treat heartworm infections.

• Homeopathic nosodes
• Herbal heartworm formulas
• Pine resin
• Essential oils to repel mosquitoes (be especially careful in cats as they can be extra sensitive to oils)

While I cannot list companies or names because I don’t want to show favoritism, enter the above bullet points for internet searching and find what appeals to you.