Red dog outside in the winter scratching a tick bite

Does My Pet Really Need Parasite Medication Year-Round?

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Welcome to the Great White North

Living in Canada means we get to experience all 4 seasons in their full glory, whether we like it or not. Each season brings its own set of challenges, and these relate to our pets’ comfort and health as well as our own.


Most pet parents are aware that parasites like fleas, ticks and heartworm pose a health risk to their pets during the warmer months, but what about the colder ones?

Cold Weather Critters

The risk of coming in contact with fleas and ticks may decrease during the colder months, but that risk never goes away completely.


  • Fleas and flea eggs can’t survive in the outside environment below freezing, but they most definitely can survive on warm-bodied hosts year round like dogs, cats and wildlife. Not to mention the fact that they can survive in heated houses, or even the cozy den of your local squirrel or raccoon.
  • Ticks are dormant in the depths of winter, but any time the temperature rises above freezing, even just for a day or two, they become active and start searching for their next meal.
  • The good news is that heartworm disease, spread solely by infected mosquitos, is not a risk here in the colder months. That being said, if you plan to travel south with your pet for a winter getaway, it’s worth keeping in mind that heartworm is a year-round concern in warmer climates.


So Does Your Pet Really Need Parasite Medication in the Winter?

Well, that depends. In a very practical sense, the answer to this question is affected by 3 things:

  1. Your pet’s lifestyle
  2. Your tolerance for risk
  3. Your budget

Let’s look at a few possible scenarios:

The Gold Standard

With the goal of keeping your pet as happy and healthy as possible we recommend year-round flea and tick prevention as the safest option. Modern prescription flea and tick medications are very well tolerated, and for that reason erring on the side of caution makes sense.


The one factor that is often ignored in this equation however, is cost - these medications aren’t cheap. For a Labrador Retriever sized dog, a top-of-the-line parasite prevention program including year-round flea and tick prevention, heartworm and intestinal worm treatment from June to November, and annual testing for intestinal parasites, heartworm disease and tick-borne illnesses will cost somewhere around $600-$800 per year.


Treatwell members can arrange for a payment plan that defrays the cost of these medications over time, but even so, this is not something all pet-parents are able to budget for. If you can, that’s great, but we always feel any decision like this is worth further analysis.


This chart lays out an excellent parasite control program that we recommend for many our Treatwell Pet Care members, but there are other great products out there too!

Start With a Good Base

Using an all-in-one parasite prevention product like Nexgard Spectra (for dogs) or Revolution Plus (for cats) from June to November is a great base to build from.


  • This ensures you pet is safe from heartworm, which is generally the most serious parasite related health problem with see our patients.
  • It makes sure your pet receives intestinal deworming multiple times over the course of the year. Combined with an annual fecal test, and monitoring for signs like diarrhea, means you’re fairly well covered.
  • It provides protection against fleas and ticks in most of the higher risk moths.
  • These convenient, all-in-one products make administration simpler than ever before, although there are other options available depending on your preferences.
  • If your pet leads a low risk-lifestyle (e.g. they’re a purse-riding chihuahua, or an indoor cat), the tick and possibly flea components of these medications becomes less important, and you may want to discuss lower-cost options with your veterinarian.
The Middle Road

If you’re looking to keep costs down, and you’re willing to tolerate some risk, then reconsidering flea and tick medication in the colder months is the place where there is the most room to move.


Keep in mind the following if you decide to omit flea and tick medication for part of the year - Fleas and ticks are not only annoying and gross, but they can also spread diseases like tapeworms infections, Lyme disease and more. These health risks should not be ignored, and there’s a lot to be said for the old adage “an ounce of prevention is worth a pound of cure”. That being said, it’s worth mentioning that these diseases are treatable, and in all but the rarest of cases treatment is usually easy and effective once a diagnosis is made.


December through February are arguably the lowest risk months for parasites, so many pet-parents will forgo coverage in those months, and start flea and tick prevention again in March or April when the weather begins to warm. This is not a bad approach if you’re willing to accept some risk, and still other pet-parents may delay restarting these medications even longer…. We just ask that you be proactive with tick checking your pet, and watching for flea-related itching if you take this approach!

So Which Decision is Right for My Pet?


In the end, every case is different, and with so many parasite-prevention products on the market making a decision can be difficult. Your best bet is to have a frank discussion with your veterinarian about figuring out which plan is best for you and your pet.


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