Keep your dog safe from heartworm disease

If you are planning on taking your dog abroad on holiday with you, one of the things you need to plan for is the risk of canine heartworm. Because this parasite can cause serious and potentially fatal disease in your dog, prevention is extremely important if you are travelling to an area where heartworm is found. Contact your local Healthy Pet Club practice and make an appointment well before you leave home to make sure your dog is protected.


Heartworms are long, hair-like worms that live in the heart and major arteries of dogs. Adult worms can grow up to 30 cm in length. This parasite, which is spread by mosquitoes, is common in Australia, America, Spain, Italy and southern France. Recent changes in climate have allowed the parasite to spread closer to the UK, and it is has recently been reported in Brittany in northern France. So if you take your dog on holiday in any of these regions, he is at risk of becoming infected with heartworm.

Problems caused by heartworm

Signs of heartworm infection include:

  • Mild persistent cough
  • Reluctance to exercise
  • Fatigue
  • Decreased appetite
  • Weight loss
  • Swollen belly
  • Collapse

Symptoms usually start between 6 and 12 months after infection.

How dogs catch heartworm

Canine heartworm is spread by mosquitoes. The heartworm larvae carried by the mosquito enter the dog through the mosquito’s bite wound. It then takes about 6 months for the larvae to develop into adult heartworms – it is at this point that they cause symptoms.

Prevention of heartworm

Prevention of heartworm is extremely important because if the parasite develops within the heart, severe disease will result. Effective prevention requires 2 approaches:

  • Prevention of mosquito bites; this can be achieved using a drug-impregnated collar or
    a spot-on treatment
  • Preventing the worm from developing in your dog if it does become infected; this can
    be achieved using a monthly spot-on or tablet treatment

    • This treatment should be started before you leave home and continued for a
      short period after you return to the UK