Parasite Protection

Year-round prevention to keep your pet and family safe from dangerous parasites.

Our city’s changing climate is gradually increasing the parasite risk to our pets...and us. Fleas have always been an itchy and painful nuisance, but the tick risk in Toronto is increasing every year. Black-legged ticks transmit Lyme Disease, the Lone Star tick causes alpha gal syndrome (which makes humans allergic to red meat), and brown dog ticks can live indoors and cause home infestations. Heartworm risk is also rising due to high infection rates among the coyotes living in our parks and ravines, and the increasing numbers of globe-trotting dogs in Toronto.  

Fleas, ticks, ear mites, intestinal worms and heartworms aren’t just icky or annoying – their impact on your pet can range from discomfort and pain to life-threatening blood loss, complications, or even death. Some of these parasites can also infect your home and spread to humans. To protect your pet and your family, both parasite testing and parasite protection medication are essential parts of your pet’s healthcare plan. 

Are fleas really that harmful to my pet? 

Fleas are incredibly uncomfortable for your pet...but their risks go far beyond that. They are so horribly itchy that cats and dogs create wounds by scratching at them, which can get infected. Many pets are allergic to their saliva and develop painful skin disease when bitten by fleas. Fleas also spread tapeworms and bartonella (cat scratch fever, which can also be transmitted to humans). If there are many fleas feeding on your pet, they can actually lose enough blood to become anemic – especially kittens and puppies. Fleas are usually out in full force after 3 days of warm weather, so we see dogs and cats with fleas all year long! And unfortunately, each female flea lays hundreds to thousands of eggs, so they quickly infest your home. Fleas are far easier to prevent than they are to treat!  

Are ticks in Toronto dangerous to dogs and cats? 

Ticks are very common in Toronto now and any pets that go outside are at risk. Many of our parks (such as High Park, Trinity Bellwoods, and Cherry Beach) are well-known tick hotspots, and popular weekend or vacation destinations like Humber Bay Park, the Rouge Valley, cottage country, and the Kingston/1000 Islands area are even worse. It is common to find dozens of ticks on dogs after a walk in these areas – and it's very important to check yourself too! We are also starting to see a lot more ticks on cats, even if they just have supervised backyard visits, since cats like to explore the grasses and shrubs where ticks are often found. Ticks are a year-round risk in Toronto now: they go dormant when the temperature is below freezing but wake up every time it warms up to 0 degrees, which happens even in the coldest winter months. 

In Toronto, the ticks that pose a risk to dogs and cats are the black-legged (deer) tick, the American dog tick, the brown dog tick, and the Lone Star tick. The most common disease they transmit is Lyme disease, but they can also spread ehrlichiosis, anaplasmosis, bartonellosis, babesiosis, Rocky Mountain Spotted Fever and cytauxzoonosis, or even cause Tick Paralysis from the bite itself. These illnesses can cause bleeding disorders and anemia, lameness and joint problems, organ damage, paralysis and even death.  

Ticks are so small before they feed that they can be virtually impossible to spot on your pet

Is heartworm disease a risk for dogs and cats in Toronto? 

Heartworms can be fatal and all pets are at risk, even if they don't spend a lot of time outdoors. They are transmitted by mosquito bites – and if you’ve ever had a mosquito buzzing around your bedroom at night, you know that they don’t just stay outside! Once a mosquito has bitten a dog, coyote, fox or wolf with heartworm, they transmit heartworm larvae to every future dog, cat, ferret and susceptible wild animal that they bite. These larvae grow into foot-long worms that live in the heart, lungs, and associated blood vessels, causing severe lung disease, heart failure, and other organ damage. Dogs have the highest risk because they are the natural host for heartworm. Cats are “atypical hosts” so their heartworms don’t usually survive to adulthood, but when they do there is no effective treatment, so the disease is even more deadly.  

Heartworm disease is still uncommon in pets in Toronto, thanks to the wide use of preventative medication, but your pet is at risk if they aren’t protected. Infection rates are high among the coyotes that live in our neighbourhood, and pets from the southern US and tropical countries can also bring it to Toronto. Fortunately, heartworm disease is easy to prevent with medication that kills heartworm larvae before they can reach the heart and mature - as long as pets take it every month during the entire risk period from June to November.  

How do pets get intestinal parasites, and what do they do? 

Your pet can get intestinal parasites such as roundworms, tapeworms, hookworms, whipworms, giardia or coccidia at any time of the year. These are spread by contact with other animals, feces, or contaminated dirt, or by eating infected prey like rodents or bugs.  

Intestinal parasites can cause diarrhea, vomiting, weight loss, dehydration, malnutrition, anemia, and intestinal obstructions, and weaken cats and dogs so they are more susceptible to other infections and diseases. Without treatment they can be deadly, particularly for puppies and kittens. Some intestinal parasites are also zoonotic, which means that they can infect people too. Click here to learn more about intestinal worms and what you can do to help prevent them from spreading to your family. 

How can I treat and prevent parasites in my dog or cat? 

Our veterinarians can prescribe all-in-one monthly medications that prevent fleas, ticks and heartworms and kill most intestinal worms. These medications are pesticide-free (unlike many dangerous over-the-counter flea and tick products) and are very widely used with few side effects. You can easily request your pet’s parasite protection medication online here

In addition to taking preventative medication, annual Accuplex testing for heartworms and tick-transmitted diseases is very important for dogs. (There is no equivalent reliable test for cats.) Despite their owners’ best intentions, very few dogs receive perfectly administered year-round preventative medication, and by the time clinical signs of heartworm and some tick-borne diseases are visible, their damage can be permanent. Even with intensive treatment they can be fatal; the earlier these diseases are diagnosed, the better the chances for recovery. Learn more about Accuplex testing.

Annual fecal testing for intestinal parasites is also important: even indoor pets can get them, they may have no symptoms, and they can spread to other pets and family members. Our recommended all-in-one parasite prevention medications kill the most common intestinal worms. However, they don’t kill all species of worms, or the common single-celled parasites giardia and coccidia. By bringing a fresh fecal sample to your pet’s annual health checkup, we can test for and treat any intestinal parasites that your pet has picked up over the year.  

How often do I need to treat my pet for parasites?

We recommend year-round once-a-month parasite prevention & treatment for dogs and cats that go outside (yes, the porch or backyard counts!) and at least once-a-season treatment for 100% indoor cats. Remember that dogs and cats are only protected from heartworm if they take monthly preventative medication for the entire June to November risk period. You can request medication for your pet using our online Parasite Prevention Request Form.

Parasite Prevention Request Form

Practice information

Roncy Village Veterinary Clinic

  • Mon
    8:00am – 7:00pm
  • Tue
    8:00am – 7:00pm
  • Wed
    8:00am – 1:00pm & 3:00pm – 7:00pm
  • Thu
    8:00am – 7:00pm
  • Fri
    8:00am – 7:00pm
  • Sat
    8:00am – 2:00pm
  • Sun
    Closed (Sundays & Holidays)

After-Hours Emergencies

Please call:


Find us here:

215 Roncesvalles Avenue Toronto, Ontario M6R 2L6
get directions with Google Maps

For after-hours emergencies, please call: