Lungworm in dogs


  • Lungworm infection is becoming much more common, and is now a risk to dogs across much of the UK.
  • Your dog is at risk of catching lungworm if they eat slugs and snails, which often happens when they eat grass.
  • Lungworm infections are serious because lungworm travels around the whole body and causes problems such as breathing difficulties, bleeding problems, seizures and even death.
  • Make sure your dog’s worming routine includes lungworm protection.
  • Ask your vet which worming product is best for your dog.

General information

A phot of snails on a tree stump with a dog sitting in some grass in the distance

Lungworm (Angiostrongylus vasorum) is a parasite that can cause severe illness and even death. Despite its name, it actually travels around the whole body and can cause breathing difficulties, heart failure, seizures, bleeding disorders, and even death. It’s important and easy to prevent lungworm by making sure your dog’s normal de-worming regime includes lungworm protection.

How do dogs catch lungworm?

A photo of a dog sniffing a patch of damp ground near a snail

Dogs catch lungworm by eating infected slugs and snails, which often happens by accident whilst eating grass or drinking outside.

Symptoms of lungworm

The symptoms of lungworm can be difficult to spot because they are often very vague and varied. They tend to vary depending on how many worms your dog has inside them and which organs they reach. Common symptoms include:

  • Coughing
  • Breathing problems (fast, heavy, noisy)
  • Weight loss
  • Unexplained bruising and bleeding
  • Seizures
  • Collapse and shock
  • Blindness.

When to contact your vet

Contact your vet immediately if your dog has symptoms of lungworm. If you need advice on how to prevent lungworm, contact your veterinary practice for advice.


Treatment for lungworm depends on how severe your dog’s infection is and what symptoms they have - there is no one treatment that fits all.

Kill the lungworm

Your vet will kill the lungworm with a deworming product. Your dog will be carefully monitored during this process because killing lots of worms at once can cause an allergic reaction and be fatal.

Hospital treatment

Mild lungworm infections often only require lungworm treatment and medication to go home with, but if your dog is seriously ill, they may need intensive care in the veterinary hospital.

  • Oxygen. Your dog may need oxygen if their lungs have been damaged by lungworm.
  • A fluid drip. Your dog may need a fluid drip (fluids given straight into the blood stream) to stop them becoming dehydrated while they recover.
  • A blood transfusion. If your dog has lost a lot of blood, they may need an emergency blood transfusion.
  • Other medications. Other medications such as anti-seizure medication may be necessary depending on your dog’s symptoms.


Preventing lungworm is much easier than treating it. If your dog is diagnosed and treated early (before severe symptoms have developed), their outlook is likely to be good. However, lungworm infections that cause symptoms such as breathing difficulties and seizures, generally have a poor outlook and sadly, severe lungworm infections can be fatal.

Ongoing care

If your dog has recovered from a severe lungworm infection, you will need to monitor them for ongoing issues such as breathing problems and seizures. In some severe cases, lungworm infections can cause ongoing problems throughout life.

Preventing lungworm

A photo of a dog being fed

It’s easy to prevent lungworm, just make sure your dog’s de-worming products include lungworm protection. There are many different products on the market, speak to your vet if you are unsure about which one to use. Always protect your dog with a veterinary licenced product.

WARNING: There are currently no lungworm treatments available without a prescription. Products you can buy without a prescription (from a supermarket, pharmacy, pet shop or online) are not veterinary licenced and often contain less effective ingredients.


Treating a lungworm infection can be expensive, especially if your dog needs intensive care. It’s very important to speak openly to your vet about your finances, the cost of treatment, as well as what you think is right for your dog.

When you welcome a new dog into your life, consider getting dog insurance straight away before any signs of illness start. This will give you peace of mind that you have some financial support if they ever get sick.

Published: April 2020

Written by vets and vet nurses. This advice is for UK pets only. Illustrations by Samantha Elmhurst.