Lungworm live in the arteries of the lungs and heart. They are about 2 to 5cm long, so can cause obstruction in the blood vessels. They multiply by releasing the larvae, which are coughed up from the lungs, swallowed and passed out in the faeces. These larvae are then taken up by snails and slugs which act as intermediate hosts, where the larvae develop and are then eaten by dogs or foxes.
The signs of infection can vary greatly and many dogs may not show any signs at all. The worms can be carried by the dogs for months or even years before any signs are shown. The signs can be vague, such as weight loss or poor weight gain, lethargy or vomiting. There can also be much more serious problems, such as blood clotting faults, showing as haemorrhages in the mouth or under the skin, coughing up blood, or blood in the faeces. Also because of where the worms live, they can cause lung and heart disease as well and occasionally they will affect the brain, causing seizures or paralysis.
As long as these symptoms are not severe, treatment is very successful, although it is much better to prevent the problem. Regular worming with the correct wormers, will keep lung worm disease down and removing faeces from the environment will help to keep these areas clean, as larvae can survive for along time on the ground.
To detect lungworm infection, we can test the faeces for the larvae or take a blood test for antibodies. The larvae are not passed out in every sample of faeces so if larvae are not found, we can not guarantee that your dog is lungworm free. It is recommended to take at least 3 samples at a few days apart to check if lungworm is suspected.
If you have any concerns about lungworm and it’s effects, please speak to your veterinary surgeon.