Lungworm more prevalent in young dogs not wormed regularly

Young dogs and those that are not wormed regularly are significantly more likely to be infected with the life-threatening, parasitic lungworm, Angiostrongylus vasorum, according to new research from the University of Bristol.

Lungworm is now widespread throughout southern Britain, with reports of cases further north. Veterinarians are advised to be vigilant for lungworm-associated disease.

In the first study of its kind in Great Britain, scientists in Bristol’s School of Biological Sciences tested the faeces of almost 900 dogs for lungworm to look for factors which may increase a dog’s risk of infection and to identify signs of infection.  Lungworm was found to be a common cause of disease in Southwest England and Wales - 16 per cent of dogs presenting symptoms tested positive for lungworm, as well as 2 per cent of seemingly healthy dogs.  However, this is likely to be an underestimate.

Dogs under 18 months were found to be 8 times more likely to have lungworm than dogs over 8 years old, and dogs between 18 months and 8 years old were 4 times more likely to have lungworm than dogs over 8 years old.  Dogs tested positive for lungworm year-round but there was an increase in numbers diagnosed during the winter and spring.

Infected dogs may display a wide range of symptoms and diagnosis is challenging. While over half of infected dogs were reported to be coughing or having difficulty breathing, lungworm infection is not always associated with respiratory signs. Infected dogs may present any combination of a wide range of symptoms including lethargy, tiring easily with exercise, and gastrointestinal signs such as vomiting and diarrhoea.  A significant number of infected dogs displayed signs of bleeding disorders such as excessive bleeding from small wounds or following surgery, blood in the urine and vomit, pale skin and bleeding in the eyes and skin.

Dr. Eric Morgan who led the research, said: “This parasite can cause serious disease and is spreading, reaching many new areas (including Bristol and Scotland) in the last few years.  Disease can present in a variety of ways, not necessarily involving respiratory signs, so pet owners and their vets should be aware of the risk.  Disease is most common in younger dogs, though age is not a barrier to infection.  On the bright side, dogs that are treated regularly with appropriate wormers are at lower risk, so we can act to protect our pets’ health.”