Snails Are the Spring Hazard You Didn’t See Coming

As temperatures rise and the blossoms appear, spring feels just around the corner. For dog parents, it’s a welcome excuse for longer walks and more time outdoors, but it also marks the return of a hidden danger. Slugs and snails, often seen as nothing more than garden pests, can carry a parasite that poses a serious threat to your dog. In areas like Southern England and South Wales, that risk can be especially high.

What is lungworm?

Lungworm is a parasitic infection found in dogs in the UK, caused by Angiostrongylus vasorum, that affects the lungs, heart and blood vessels. If left untreated, it can lead to serious complications including, breathing problems, neurological issues and even death. 

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Once inside the body, the larvae develop into adult worms which can migrate through the bloodstream. They can live in the heart and surrounding blood vessels, disrupting normal breathing and blood clotting.

How do dogs get lungworm from snails and slugs? 

Dogs typically become infected by coming into contact with infected slugs, snails, frogs or even their slime! 

Common ways dogs pick up lungworm include:

• Eating slugs, snails or even frogs carrying the larvae.

• Eating grass or objects contaminated with slime trails.

• Drinking from outdoor water bowls or puddles.

• Chewing toys that have been left outside.

• Grooming larvae off their fur after outdoor play.

• Eating discarded food left outside.

After infection, larvae grow inside the dog. Around four weeks later, adult worms begin producing new larvae, which are passed in the dog’s faeces, continuing the cycle by infecting more slugs and snails. 

It’s important to note:

• Lungworm cannot spread directly from dog to dog.

• It is different to the lungworm seen in cats.

• It does NOT infect humans.

Lungworm symptoms in dogs

Symptoms can be mild at first or vary depending on how many worms are present and where they are in the body. 

Signs of lungworm include:

• Breathing difficulties (fast, heavy or noisy breathing).

• Persistent coughing or coughing up blood.

• Lethargy or reduced energy.

• Weight loss or loss of appetite.

• Vomiting and diarrhoea.

• Unexplained bruising or bleeding (including nosebleeds or bleeding gums).

• Pale gums.

• Wobbly gait or coordination problems.

• Seizures, collapse or even blindness in severe cases.

Some dogs may only show subtle signs initially, while others can become seriously ill very quickly.

Which dogs are most at risk of getting lungworm?

Sadly any dog can get lungworm – it doesn’t have favourites – but certain factors increase the risk:

• Young or curious dogs who explore with their mouths.

• Dogs with regular outdoor access (gardens, parks, rural areas).

• Dogs prone to eating grass or scavenging.

• Dogs in high-risk regions, particularly Southern England and South Wales.

There is also a seasonal increase in spring and autumn, when slugs and snails are most active. 

How to prevent lungworm in dogs

Prevention is far safer and like many things is far cheaper than treatment. 

Key steps include:

• Using regular preventative treatment: lungworm prevention requires a vet prescription in the UK. Spot-on or tablet treatments are available, but not all parasite products cover lungworm so always check with your vet.

• Consider a monthly pet healthcare plan: many UK vets offer schemes that include parasite control.

• Don’t leave toys outside: slugs and snails can crawl over them overnight.

• Clean outdoor water bowls daily: replace water frequently to avoid contamination.

• Supervise your dog outdoors: especially if they tend to eat grass or pick up things. 

• Keep your garden less attractive to slugs and snails: reduce damp areas and remove debris where they hide.

Pet insurance is also worth considering, as treatment for severe cases can be costly. 

When to call your vet

If you’re worried your dog may have been exposed to lungworm, you have seen them interact with a snail, slug, or their slime, or you notice any symptoms, contact your vet as soon as possible.

This is not a condition to monitor at home.

Seek urgent veterinary care if your dog:

• Has breathing difficulties.

• Shows signs of unexplained bleeding.

• Becomes suddenly lethargic.

• Has seizures, collapses or coordination issues.

How lungworm in dogs is diagnosed and treated

Diagnosis typically involves:

• A full clinical history including parasite treatments.

• Blood tests.

• Faecal samples (though these can be unreliable).

• Chest X-rays to check for lung damage.

Treatment depends on severity:

• Mild cases: deworming medication, with careful monitoring (as dying worms can trigger reactions)

• Severe cases: hospitalisation, oxygen support, IV fluids and possibly blood transfusions.

• Additional care: anti-seizure medication or long-term management if damage has occurred.

However the good news is that most dogs recover well when diagnosed and treated early.

Lungworm is an invisible but very real risk for UK dogs, especially in the spring. Infection can happen easily, so prevention and early action are critical. If in doubt, always speak to your vet – it’s a simple step that could save your dog’s life. 

Frequently asked questions: lungworm in dogs

Can dogs die from lungworm?

Yes, lungworm can be fatal, particularly in severe or untreated cases. Early treatment significantly improves outcomes.

How quickly does lungworm develop in dogs?

Larvae can begin developing into adult worms within weeks, with new larvae being produced and spread after around four weeks.

Is lungworm common in the UK?

Yes, lungworm is increasingly common across the UK, particularly in Southern England and South Wales.

Can lungworm spread to humans?

No. Angiostrongylus vasorum only affects dogs and cannot be passed to humans.