Lungworm infection in dogs is a serious and potentially fatal parasitic infection which is caused by a very small worm (nematode). The worm is widespread in the UK fox population and the fox is therefore referred to as the reservoir host.  

Clinical disease due to lungworm is not a common problem. However, it is more commonly reported in some areas than others and lungworm numbers as a whole may be on the increase due to factors such as climate change.

Adult worms actually live and mate in the blood vessels leading to the lungs. Eggs are then laid in these vessels and after hatching the small worm larvae appear. The larvae then enter the lungs where they cause inflammation and irritation before they are coughed up, swallowed and passed out in the faeces.

Once on the ground, larvae are picked up by slugs and snails which are referred to as the intermediate host. The larvae can now pass to other dogs and foxes if they eat these molluscs or even by licking the slime trail they leave behind.

It is natural to think that lungworm is a countryside problem but one study has suggested that over 70% of urban foxes in London are infected. Therefore, unfortunately the risk is present almost everywhere. 

Prevention of lungworm in your dog

Don’t leave dog toys or feeding bowls outside where they may attract slugs and snails. Food is particularly good at attracting slugs. Clean outside water bowls regularly. 

Pick up your dog's poo to prevent any spread to other dogs.

There are several medications licensed to prevent lungworm infestation. Your veterinary surgeon will advise about the local risks in your area and the best medication to use if you want to protect your dog.

There are “spot on” preparations and tablets available which kill lungworm effectively. To be effective as a preventative these treatments have to be taken regularly and at the correct intervals, your vet is best placed to advise you on the specific treatment for your dog.

How do you know your dog is affected?

In the early stages of infestation and in mild cases you may see no symptoms at all. However, when clinical signs are seen they can be very varied and are similar to many other less serious conditions. Signs of lungworm infection include:

Coughing

Weight loss

Lethargy

Bleeding such as nose bleeds due to poor clotting of the blood

Tiring easily

Even seizures.

The most dangerous effect of lungworm infestation is caused by the parasite secreting material that prevents the blood clotting. This can lead to serious bleeding and this is the cause of the rare fatalities that do occur. 

Your vet can perform tests on blood or a faecal sample to identify the presence of lungworm, sometimes this can be completed in the clinic in a few minutes.

Some clinics will recommend a test prior to surgery as an unknown infestation might increase the risk of bleeding following the surgery.

The dog’s lungworm cannot be transmitted to humans.

If you think that your dog may have lungworm then you should contact your veterinary surgery as soon as possible.