Dog Health
Heartworm vs Lungworm in Dogs UK — How to Tell Them Apart
Published Last updated 3 min read
Quick answer
Lungworm and heartworm are not the same parasite. In the UK, lungworm (Angiostrongylus vasorum) is the main concern — spread by slugs and snails. Heartworm (Dirofilaria immitis) is rare in Britain but matters for dogs travelling to southern Europe. Prevention products differ — ask your vet.
Quick comparison
| Feature | UK lungworm | Heartworm |
|---|---|---|
| Parasite | Angiostrongylus vasorum | Dirofilaria immitis |
| Spread | Slugs, snails, slime trails | Mosquito bites |
| UK prevalence | Widespread and increasing | Rare (mainly travel/import cases) |
| Main signs | Cough, bleeding, neurological signs | Cough, exercise intolerance, heart failure |
| Prevention | Monthly vet wormers that cover lungworm | Travel-specific heartworm preventatives |
UK lungworm — the priority for most owners
According to the PDSA and BVA, lungworm has spread across much of England, Wales, and Scotland. Dogs ingest larvae from:
- Eating slugs or snails
- Licking slime trails on grass, toys, and outdoor bowls
Warning signs include coughing, bleeding (nosebleeds, pale gums, bruising), weight loss, seizures, and collapse.
Full guide: Lungworm in dogs UK
Not all wormers cover lungworm — check your dog worming schedule with your vet.
Heartworm — UK context
Heartworm larvae are spread by infected mosquitoes. Worms mature in the heart and pulmonary arteries over months, causing progressive heart and lung disease.
Is heartworm a UK problem?
Native UK infection is uncommon. The BVA notes heartworm as a travel and import concern — dogs visiting or relocated from southern Europe, the Mediterranean, and other warm regions may be at risk.
UK owners should discuss heartworm prevention with their vet before travel abroad — see Travelling with pets UK.
Full guide: Heartworm in dogs
Overlapping symptoms
Both parasites can cause:
- Coughing — see Why is my dog coughing?
- Exercise intolerance — see Why is my dog panting heavily?
- Weight loss — see Unexplained weight loss in dogs
Bleeding disorders are more characteristic of lungworm. Heart failure and fluid belly are more typical of advanced heartworm.
Only veterinary tests can confirm which parasite — or another condition — is involved.
Prevention summary for UK dogs
- Year-round lungworm prevention — vet-prescribed product that explicitly covers A. vasorum
- Routine intestinal worming — roundworm and tapeworm per worming schedule
- Travel heartworm prevention — if visiting at-risk countries, start before travel per vet advice
- Never use dog wormers on cats without veterinary direction
When to see your vet urgently
Seek emergency care for:
- Collapse, severe breathing difficulty, or seizures
- Nosebleeds or unexplained bleeding
- Pale gums or sudden weakness
Related guides
Sources & further reading
Facts in this guide are rewritten in plain English from publicly available UK advice. We name the organisation where a specific point comes from their guidance. Links below go to the original pages — use them to read the source material directly.
PETHEALTH+ is independent. These organisations do not sponsor, approve, or partner with this website. Guidance checked against sources listed below (last updated 2026-06-25).
Related guides
- Lungworm in Dogs UK — Angiostrongylus Vasorum Symptoms & Prevention
- Dog Worming Schedule UK — Puppies, Adults & Lungworm Prevention
- Travelling With Pets in the UK — Cars, Trains, Eurotunnel & Safety
- Heartworm in Dogs UK — Travel Risk, Symptoms & Prevention
- Why Is My Dog Coughing? Common Causes & When to Worry
- Why Is My Dog Panting Heavily? UK Heat, Pain & Emergency Signs
Frequently Asked Questions
- What is the difference between heartworm and lungworm in dogs?
- They are different parasites. UK lungworm (Angiostrongylus vasorum) spreads via slugs and snails and is common in Britain. Heartworm (Dirofilaria immitis) spreads via mosquitoes and is rare in the UK but a risk after travel to southern Europe.
- Is heartworm common in the UK?
- No — native UK heartworm infection is uncommon. Cases are usually linked to travel abroad or imported dogs. Lungworm is the parasite UK owners should prioritise for prevention.
- Do the same wormers prevent both?
- Not necessarily — many standard wormers do not cover lungworm. Some travel products cover heartworm. Your vet will recommend products based on UK lungworm risk and any travel plans.
- Can a dog have both heartworm and lungworm?
- Theoretically yes in a dog with UK lungworm exposure and travel-related heartworm risk — but this is uncommon. Veterinary blood tests help identify which parasite is involved.