“Do I Really need to Give My Pet Heartworm, Flea & Tick Prevention Year-Round?” – Yes, Yes You Do. Here’s Why

– By Allison Sanders, DVM

Let’s talk about a question I hear all the time in the clinic:

“Do I really need to keep my dog or cat on heartworm, flea, and tick prevention all year? Even in the winter?”

In short: Yes.
In long: Yeeeeeeeeeeees.In fact, I’ll go ahead and say it louder for the people in the back: YES.

I know it might feel like the bugs go away in the winter. It is COLD outside, right? But nature doesn’t sleep, and parasites are sneakier than you think.

Let’s Break It Down

Heartworm:

Heartworm is transmitted by mosquitoes. Most people think mosquitoes vanish the minute temps drop. Unfortunately, they don’t. All it takes is a warm snap—above 50°F—for mosquitoes to reappear.

Also worth noting: heartworm preventatives don’t actually prevent heartworms from entering the body. They kill the early-stage larvae your pet was exposed to last month. If you skip a month, you’re giving baby heartworms the green light to set up shop.

Translation: heartworm prevention is retroactive—missing a dose = opening the door to invaders.

Fleas:

Fleas are basically the zombies of the parasite world. They can survive in cool temps, inside your house, on wildlife, in bedding, in your car—anywhere your pet hangs out. Once inside, they multiply like it’s their full-time job. Miss a dose, and you might go from zero to infestation faster than you can say, “Why is my dog scratching at 2 a.m.?”

Fun (horrifying?) fact: One adult flea can lay up to 50 eggs per day. That’s 350 flea babies in a week. That’s… too many.

Ticks:

Now here’s where it gets really wild. Ticks don’t die in the winter either. They quest.

Yes, quest. Like tiny, disgusting little adventurers.

When temperatures rise above freezing (32°F), ticks become active—even in the dead of winter. They crawl up to the tips of grass blades, stretch out their nasty little legs, and wait. That’s called “questing”. They’re waiting to latch onto your pet (or you, sorry) as you brush
by.

Your pet doesn’t even have to go deep into the woods. Ticks are in your yard. They’re on leaf litter. They’re on neighborhood trails. They’re doing yoga in the bushes waiting for someone warm and full of blood to wander by.

But Isn’t Year-Round Prevention Expensive?

You know what’s more expensive than monthly prevention? Treating heartworm disease. Or flea allergies. Or Lyme disease. Or your soul slowly dying as you wash every blanket in your house for the eighth time because fleas got in.

Veterinary prevention may feel like an investment, but it’s a lot cheaper than treatment— financially and emotionally. Plus, many manufacturers offer rebates and guarantees when you buy through a veterinary clinic like Bowman Animal Hospital.

Don’t Forget the Cats

Yes, even indoor cats should be on prevention. Fleas, mosquitoes, and even ticks can and do get into homes. Ever opened a door? There you go. Parasites are tiny hitchhikers, and once they’re in, they don’t need a lot of encouragement to start multiplying.

And yep—cats can get heartworms too. It’s less common, but way more dangerous. There’s no treatment for feline heartworm, just supportive care. So prevention is really the only option.

Final Thoughts…

Parasites don’t follow the calendar. They don’t care if it’s pumpkin spice season or snowpocalypse. They just want a warm host and a place to hang out (and suck blood). That’s why year-round prevention is not just smart—it’s essential.

Keep those preventatives going, 12 months a year. Your pet (and your couch cushions) will thank you.

Stay safe, stay parasite-free, and give your pets a boop from me.
-Dr. Sanders