PetHeartworm is a mosquito-borne parasite that lodges in a dog's heart and lungs, and treating an established infection is serious, slow, and far more expensive — and risky — than preventing it. In Canada it's a regional risk, present in parts of Ontario, Quebec, and Manitoba, and testing is a routine spring ritual for dogs in those areas. Here's what treatment actually costs, and why almost every vet will tell you prevention is the smarter spend.
What it costs in Canada
| Scenario | Typical cost (CAD) |
|---|---|
| Heartworm test (routine screening) | ~$40–$120 |
| Staging — bloodwork, X-rays to assess severity | ~$200–$600 |
| Melarsomine injection series (adulticide) — all in | ~$500–$1,500+ (scales with dog size) |
| Doxycycline + steroids + supportive meds | ~$100–$400 |
| Advanced / severe cases (hospitalization, complications) | ~$1,500–$4,000+ |
| Monthly / seasonal prevention (the cheaper path) | ~$10–$30/month in mosquito season |
These figures are estimates for general guidance only, not quotes, compiled from publicly available Canadian veterinary pricing. The main drivers are your dog's size (the melarsomine dose is weight-based), how advanced the infection is, and whether complications develop. Treatment also demands weeks of strict rest — a real practical burden — because killing the worms while a dog is active can be dangerous. Prevention costs a small fraction of treatment and avoids the risk entirely. See How we estimated these costs.
With insurance vs paying out of pocket
| Scenario | You pay | Insurer pays |
|---|---|---|
| No insurance | Full $500–$1,500+ (more for advanced cases) | $0 |
| Comprehensive policy (in force before infection) | Deductible + co-insurance share | Staging, injections, meds, hospitalization, up to limits |
| Heartworm prevention | Usually paid in full | Not covered by standard plans (some wellness add-ons include it) |
| No policy until after diagnosis | Full cost — heartworm is pre-existing to any new policy | $0 |
Why treatment is such a big deal
Treating adult heartworms isn't a simple course of pills. The standard treatment is a series of melarsomine injections that kill the adult worms, usually preceded by doxycycline and steroids and combined with weeks of strict rest. That rest is the hard part: as the worms die, fragments can lodge in the lungs, and a dog that runs or jumps during this window can suffer a life-threatening clot. So treatment is not just costly — it's a slow, careful, several-week process that's stressful for dog and owner alike.
Prevention is the whole point
Every vet will make the same case: prevention is far cheaper and far safer than treatment. A monthly (or seasonal) heartworm preventative costs a small fraction of a treatment course and eliminates the risk of the disease and its dangerous treatment altogether. In heartworm regions, dogs are typically tested each spring and kept on prevention through mosquito season. Skipping prevention to save a little is the classic false economy — one infection costs many times a year of protection.
Does heartworm treatment cost vary by city?
The treatment protocol is fairly standard nationally, but your exposure risk is regional: heartworm is established in parts of southern Ontario, southern Quebec, and Manitoba, and is rare in much of the rest of the country. Dogs in endemic areas — or dogs that travel to them, or come from the southern US — are the ones at real risk. Advanced cases needing hospitalization usually mean a referral hospital, concentrated in major metros. Ask your vet whether heartworm prevention is recommended where you live and travel.
How insurance covers heartworm
Comprehensive (accident-and-illness) pet insurance covers heartworm treatment as an illness — the staging, injection series, medications, and any hospitalization — provided the infection wasn't pre-existing before your policy started. What standard plans don't cover is prevention (the monthly preventative and routine testing), since that's preventive care — though some wellness add-ons include it. The pattern is familiar: insure a healthy dog, keep up prevention, and treatment is covered if it's ever needed. See best pet insurance in Canada.
How we estimated these costs
The dollar figures here are estimates for general guidance, not quotes, compiled from publicly available Canadian veterinary pricing. Real costs vary by clinic, province, your dog's size, and the stage of infection — confirm with your own vet. Sources we drew on:
- Canadian heartworm testing, treatment, and prevention cost ranges: our Canadian Vet Cost Index, compiled from publicly available Canadian pricing.
- Complication context from our own hospitalization and heart disease cost guides.
Considering insurance?
Heartworm treatment runs $500–$1,500+ and demands weeks of strict rest — while prevention costs a fraction of that. Comprehensive insurance covers treatment if you enrolled before infection. Keep up prevention and insure a healthy dog. Compare Canadian plans.