Can My Dog Get Heartworms in the Winter Months?


Dog Parasites

This is a popular question among dog owners. Heartworms are a debilitating disease that can reduce your dog’s quality of like or end it if left untreated. Since heartworms are transmitted via mosquitos and mosquitos are only present during warm weather in the summer, it would stand to reason that your best friend wouldn’t be susceptible to heartworms in the colder months. So why is there all this fuss about taking year-long medication?

First of all we need to talk geography. This parasite is present in all fifty states, with warmer and wetter states have more mosquitos and thus more chances that your dog will become infected. You don’t notice the infection right away because the eggs need time to settle and grow before they travel to the dog’s heart and lungs. The heartworm becomes fully grown and dangerous in six to seven months from the initial infection. While mosquitos are a well known nuisance during the summer time, they also may bite in the fall and winter if the weather is mild enough and wet enough.

Why should I medicate my dog year-round?

Many pet owners are skeptical of any reason that the pharmaceutical companies give for your pet to take medication year-round; aren’t they in business to make money? The cost of a year-round preventative treatment for your dog can run anywhere from $5 to $15 per month depending on what kind you get and the weight of your dog. Many offer treatment against other pests that are still contagious in the winter months. To eliminate full grown heartworms, the cost is anywhere from $300 to $1,000 and by that point any damage that has been done is already permanent. If the pharmaceutical companies wanted to make big money, they wouldn’t be selling preventative treatment. With regular treatment, heartworms are easily preventable with medication. It is difficult and costly to cure the condition and your dog’s quality of life will suffer.

Dog Heartworms

Most preventative medications are topical or ingested. There’s even an injectable medication that can protect your dog for up to six months. Heartworm preventative medications do not actually “prevent” infections – the medication kills the parasites that your pet picked up from the previous month.  So if you’re timing is off when you gave the last dose then your pet could possibly be open to infection. It’s wise to keep up the medication even when the risk is low because we are human and tend to forget to treat the dogs and miss a dose.

Most medications also protect against other year-round parasites like roundworm, whipworms, or tapeworms. If your dog has been boarded up recently or been around other animals your monthly medication ensured protection against communicable things such as ticks, lice, intestinal worms, mange, and fleas.

It’s also almost an insurance plan for your dog’s health. If your dog still gets heartworms and you have been following the instructions every month throughout the year then most manufacturers will pay to have your dog treated. With such a low cost per month it may not be in your pet’s best interest or health to save a few dollars.

As always, it’s wise and recommended to check with your veterinarian about the different type of preventative medications and the potential side effects.

Photo Credit:

WagBrag’s co-founder, Russ Boles, has a deep history in animal rescue and welfare. For the past 12 years, Russ has served in various roles with Atlanta-based animal advocacy organizations focused on rescue, training and education. In addition, Russ led a local rescue volunteer team into New Orleans immediately after Hurricane Katrina, assisting in efforts to rescue and care for stranded animals. This experience changed his life, and animal rescue and advocacy will always be a part of everything he does.