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We have had quite a few enquiries about “French heartworm” or “lungworm” following media reports of the first case in Scotland in spring last year.

The parasite that the media is referring to is called Angiostrongylus Vasorum. The adult worm lives in the heart and lung (pulmonary) blood vessels and the larvae migrate through the lungs before being coughed up, swallowed and passed into the faeces. From here the larvae is then ingested by a slug or snail and develops through a further two stages. Ingestion of the snail or even possibly of the mucus trail on food bowls or toys by the dog, results in infection. The larvae then migrate to the heart and become an adult worm thus completing the lifecycle.

Dog and snail

Clinical signs of infection usually include respiratory signs of coughing, increased respiratory rate and effort and exercise tolerance. Sometimes it can also result in clotting problems and neurological signs and in severe cases collapse.

Definitive diagnosis is from analysing 3 faecal samples for the larvae. Radiographs may also help with diagnosis.

Treatment is usually by the use of a single spot on preparation called Advocate. Alternative treatments include the wormer Milbemax once weekly for 4 weeks or another worming product called panacur for 2-3 weeks. Steroids may also be dispensed to reduce the chance of an allergic reaction to the dead worms during treatment.

Prognosis is generally good but is worse if any bleeding or neurological signs are evident and in most severe cases may be fatal.

Prevention may not be 100% possible but good hygiene of daily disposal of dog faeces and cleaning toys/dog bowls that have been outside will certainly help. Although no data is available, it would be wise to choose a product that is effective in treating the disease as a routine wormer.