Dog health in Toronto: winter paw care, Lyme disease prevention and navigating Ontario's pit bull law

Toronto sits at the intersection of three distinct dog-health challenges that dog owners moving from warmer climates — or even from western Canada — may not anticipate. The first is winter: Toronto's humid continental climate brings average January temperatures of -5°C, heavy snowfall, and the near-universal application of road salt and de-icing chemicals across the city's sidewalk network. The second is Lyme disease: the blacklegged tick (Ixodes scapularis), once absent from Toronto, has been steadily spreading northward from Lake Erie and Lake Ontario shorelines, and is now established in parts of the Greater Toronto Area. The third is legal: Ontario's Dog Owners' Liability Act bans pit bull terriers and several related breeds outright — a law with real enforcement consequences that every dog owner in the province must understand.

Winter paw care: why Toronto's roads are harder on dogs than cold alone

Most dog owners understand that cold can damage paw pads. What is less widely appreciated is that the primary mechanism of paw injury in Toronto winters is not cold temperature alone — it is the combination of salt, chemical de-icers, ice melt products, and freeze-thaw cycles that characterise Toronto's November through March period. The City of Toronto applies road salt (sodium chloride) and calcium chloride to public sidewalks, roads, and the PATH underground network. Private property managers often apply magnesium chloride, potassium chloride, or urea-based products. Each has a different toxicity profile if ingested.

Paw pad cracking and fissuring is the other major winter paw concern. Repeated cycles of wet salt exposure, drying out, and re-wetting weaken the stratum corneum (the outer keratin layer of the pad). Cracked pads bleed, are painful on cold surfaces, and create entry points for bacteria. Toronto vets see a seasonal spike in paw pad infections from January through March. Protective boots offer the most comprehensive protection — most dogs habituate to boots within one to two weeks of consistent use. If boots are refused, a thin layer of musher's wax or a product like Paw Balm applied before walks provides a chemical and moisture barrier.

Lyme disease in Toronto: understanding a growing risk

Lyme disease is caused by the bacterium Borrelia burgdorferi, transmitted through the bite of the blacklegged tick (Ixodes scapularis, also called the deer tick). In Ontario, the Public Health Agency of Canada (PHAC) tracks Ixodes scapularis populations, and the tick's established range has expanded significantly in the past decade. As of recent PHAC surveillance, established Ixodes populations exist along the north shore of Lake Erie, the Niagara Peninsula, Long Point, Point Pelee, and are spreading into the Greater Golden Horseshoe — the regional area that includes the outer GTA suburbs.

Within the City of Toronto proper, Ixodes scapularis is not yet considered established in the same density as Niagara or Long Point — but the tick has been detected in Toronto's ravine system and at Rouge National Urban Park in the east end. Dogs that regularly access ravine trails (the Don Valley, Humber River trail, Black Creek), High Park forested sections, Rouge Park, or the Toronto Zoo and Kortright Centre areas carry measurable Lyme exposure risk. Dogs are not protected by vaccination status against other disease they may acquire from ticks — Lyme vaccination (Nobivac Lyme / Recombitek Lyme) provides specific Lyme protection but does not protect against Ehrlichia, Anaplasma, or Rocky Mountain Spotted Fever.

Ontario's pit bull ban: what the law actually says

Ontario's Dog Owners' Liability Act (DOLA), amended in 2005, prohibits the ownership of pit bull terriers in Ontario. The prohibition is defined to capture four specific types: the American Pit Bull Terrier, the American Staffordshire Terrier, the Staffordshire Bull Terrier, and 'a dog that has an appearance and physical characteristics that are substantially similar' to the above breeds. The last clause — the similarity provision — has historically been interpreted broadly by animal control officers and courts.

Dogs that were owned in Ontario before the November 29, 2005 effective date were grandfathered (permitted to remain) but the last grandfathered dog would now be very old. For practical purposes, any new pit bull terrier acquisition in Ontario is prohibited, and the breed remains subject to seizure and euthanasia under DOLA. Toronto Animal Services (TAS) enforces DOLA within the City of Toronto boundaries. Breed identification disputes occur — if you believe your dog has been incorrectly identified as a prohibited breed, you have the right to request a court review. Consult an Ontario animal law specialist or the Animal Alliance of Canada for guidance.

Summer heat: Toronto's humid continental climate and heatstroke risk

Toronto's summer (July-August) brings high humidity combined with temperatures averaging 27-30°C, with heat-humidex warnings issued regularly. Unlike dry Alberta or BC heat, Toronto's humid heat prevents effective panting because the air is already saturated — dogs cannot cool themselves adequately through evaporation. Brachycephalic breeds (French Bulldog, Pug, Bulldog, Boston Terrier) and double-coated Nordic breeds (Husky, Samoyed, Malamute) are at elevated heatstroke risk on Toronto summer afternoons.

The standard guidance applies: walk before 8am or after 7pm on hot days. Test pavement temperature with the back of your hand — if you cannot comfortably hold it there for 7 seconds, it is too hot for paw pads. The Toronto and Region Conservation Authority (TRCA) issues heat alerts through the Toronto Public Health system — these apply to dogs as much as people. Never leave a dog in a parked car in Toronto in summer: Ontario's animal protection law (Animals for Research Act / Ontario SPCA Act) allows officers to intervene if a dog is in distress.

Heartworm in Toronto: a real and preventable risk

Heartworm (Dirofilaria immitis) is transmitted by mosquitoes and is endemic in Ontario. Toronto sits within a moderate-risk heartworm zone — not as high as the southwestern Ontario corridor (Windsor-London), but real enough that the Ontario Veterinary Medical Association (OVMA) recommends monthly heartworm prevention for all Toronto dogs throughout the mosquito season, typically June through November. Toronto's ravine system and proximity to Lake Ontario create standing water and mosquito habitat throughout the summer.

Annual heartworm testing (a blood test at your vet) before starting prevention is recommended — giving preventive medication to a heartworm-positive dog without treatment can cause a serious adverse reaction. Combination products (Revolution, Interceptor Plus, Simparica Trio, Advantage Multi) that protect against both heartworm and fleas are available from your Ontario vet. No Health Canada-approved heartworm preventive is available over the counter in Canada — a prescription is required.

Intestinal parasites and Ontario-specific risks

Raccoon roundworm (Baylisascaris procyonis) is endemic in Toronto's urban raccoon population, one of the densest in the world. While direct transmission to dogs is uncommon, dogs can ingest raccoon feces in parks and yards, and the larvae can migrate through tissues. The risk is low but real — prevent dogs from eating raccoon feces (or anything they find in parks) and maintain regular deworming as advised by your vet. Giardia is present in Toronto's water bodies including the Don River and Humber River — do not allow dogs to drink from these sources.

Toronto's urban environment creates one additional hazard not commonly discussed: sewer grate and storm drain falls. Dogs investigating interesting smells near storm drains on city streets occasionally fall partially through grate openings, injuring their legs or becoming trapped. This is more common in older Toronto neighbourhoods with aged infrastructure. Keep dogs away from storm drain grates when the drain covers are lifted or damaged.