How do I treat my dog for lungworm?


Lungworm is potentially fatal to dogs and is spreading across the UK at an alarming rate. Here we tell you how to protect your dog from this nasty parasite.

Dogs infected with lungworm can suffer serious health problems. Despite this, many owners have a lack of understanding about lungworm and are unsure how to spot the warning signs. We have all the information you need to know on this parasite.

What is lungworm?

The term lungworm refers to a parasitic worm called angiostrongylus vasorum, also known as French heartworm. It infects snails and slugs which carry the life-threatening parasite. If dogs swallow one of these garden visitors there's a chance they could become infected with lungworm.

Once absorbed, the worms migrate to the dog's heart where they produce eggs which enter the bloodstream and lodge in the lungs.

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Who is most at risk of lungworm?

Dogs of all ages and breeds are at risk of becoming infected with lungworm. Young dogs can be more prone to picking up lungworm and young puppies can be infested by their mothers who can pass on the worms or larvae when they're cleaning their offspring.

Dogs who love to rummage through undergrowth, eat long grass, drink from puddles, and target snails and slugs when outdoors are also more at risk.

Spotting the signs of lungworm

There are a number of signs which can indicate that lungworm is present. However, these are easily mistaken as other illnesses. Puppies may not show signs of disease until three to five months after ingestion, when the worms have developed to adulthood in the lungs.

If you suspect your dog has lungworm, contact your vet immediately.

Additionally, in today's digital age, some veterinary professionals also offer the convenience of veterinary work from home for certain consultations and advice, making it easier than ever to ensure your furry friend receives the care they need.

Symptoms of the disease can include:

  • Breathing problems.
  • A bad cough.
  • More tired than usual.
  • Weight loss and poor appetite.
  • General sickness and diarrhoea.
  • Changes in behaviour.
  • Seizures.
  • Poor blood clotting.

Lungworm is on the increase

Lungworm is no longer only seen in isolated areas. According to research by the Royal Veterinary College, the spread of lungworm in the UK is rising rapidly. Last year, the RVC conducted a nationwide survey with every small animal veterinary practice in Britain. It found that not only is lungworm widespread, with hot spots of infection in South Wales and south-east England, but that the parasite is also being seen in areas where it had not been reported previously.

Reasons attributed to the spread of lungworm in the UK include:

  • The movement of dogs around the country when they're bought from a breeder or taken on holiday.
  • Global warming encouraging more snails and slugs to remain active for longer during the year.
  • Foxes becoming infected with lungworm and acting as a source of infection for dogs, particularly in towns.
  • A greater awareness of the parasite among dog owners and vets might contribute to it being reported more frequently.
Hot spots of lungworm infection

Clusters of lungworm cases were originally reported in south-west England, South Wales, and south-east England during the 1980s and 1990s. In 2009, cases of the parasite were seen in the Midlands, northern England, and Scotland.

Top tips to stay lungworm-free

Caroline Braidwood, product group manager at Bayer Animal Health, said owners worried about lungworm should:

1. Speak to their vet about prevention and treatment; normal over-the-counter worming products don't protect dogs against lungworm.

2. Look out for the signs and symptoms of lungworm, but remember that some dogs don't display any symptoms.

3. Make sure outside water bowls are clean and the water fresh.

4. Assess their individual risk of lungworm - do you live in a lungworm hot spot; does your dog eat grass?

5. Don't let dogs drink from puddles if possible.

Postal worming test

Dogs can be tested for lungworm via a postal faecal worm egg counting laboratory. Samples of fresh poo are sent to Wormcount Dotcom via a kit provided by the company, which then tests for both angiostrongylus varsorum and oslerus osleri - another type of lungworm.

After 24 hours, the results are reported back to the owner along with a report and recommendations from an Animal Medicines Training Regulatory Authority animal health adviser.

Michaela Murray, who runs Wormcount Dotcom, said owners can then decide whether to use conventional worming methods and do a worm count test to check the method is working, or replace monthly worming with a regular worm count, only worming if the test result is positive.

Your Dog resident vet Roberta Baxter said: "Not all worms shed eggs all the time and are detectable on faeces samples, so regular worming may still be the most appropriate way to treat dogs routinely." The test costs £8.50; for further information visit

Did you know?
  • Dogs infected with lungworm spread the parasite into the environment.
  • This increases the chances of other dogs becoming infected.
  • Eighty-four per cent of people don't know the signs of a lungworm infection in dogs.
  • More than a third of owners don't know how dogs become infected with lungworm.
  • The lungworm angiostrongylus varsorum was first seen in an imported Greyhound in Hertfordshire in the mid 1970s.  

Treatment for lungworm

(A) Vet Roberta Baxter says: Milbemax is a combined wormer which has efficacy against roundworms and tapeworms and has now been given a licence for treatment and prevention of angiostrongylus vasorum, the lungworm, creating an alternative to Advocate spot-on. Whereas we normally worm dogs once monthly if they are in a high-risk group for worms or if they have close contact with babies, or once every three months otherwise, treatment of lungworm necessitates the dose of Milbemax to be given weekly for four weeks.

I would therefore recommend that Milbemax be used every one to three months for routine preventative worming against roundworm, tapeworm and lungworm, and more frequently where a problem is suspected or known. Other products have been evaluated for their efficacy against lungworm, and Panacur might also be effective.

(A) Vet Holly Mash says: The lungworm parasite is carried by slugs and snails, which are known as intermediate hosts. A dog may eat these common garden pests when rummaging through undergrowth, eating grass, drinking from puddles or outdoor water bowls, or pick them up from their toys. As far as I am aware Advocate Spot-On preparation would be the best treatment of choice for dogs.