Bayer has announced the result of a survey it commissioned from YouGov which found that 85% of British adults are unaware that foxes are a carrier of Angiostrongylus vasorum and might be responsible for spreading the potentially fatal infection to pet dogs.

It might explain why, according to the research, around 14% of British adults actively encourage fox visitors into their garden, with 10% of adults leaving out food, water or toys for foxes and 48% of them admitting they would feel disappointed if their garden fox did not return at night.

Bayer highlights research which showed an increase in the number of foxes infected with Angiostrongylus, from 7.3% in 2008 to 18.3% in 20152,3.

More recent work led by the aptly named Professor Mark Fox at the Royal Veterinary College has shown that, in the Greater London area, nearly three out of four foxes (74.4%) are infected with the parasite.4

Mark said: "We had previously mapped the distribution of Angiostrongylus in pet dogs by seeing how many cases every small animal practice in Britain had seen over the previous 12 months. This revealed the parasite’s widespread distribution coupled with hotspots of infection in Greater London/south-east England and South Wales, where dogs were four to five times more likely to be infected than elsewhere in the country.

"We then investigated why hot spots were seen in these locations and, apart from land type, dog density and climatic factors, we found that the mere presence of foxes locally increased the risk of infection in dogs five-fold."

"The overall prevalence of infection in Greater London was very high, at just under 75 per cent4, and prevalence was maintained at this level throughout the year. These results suggest that foxes act as year-round, wild animal reservoirs of infection for urban dogs."

Donna Tomlinson, Bayer Senior Brand Manager said: "The recent ‘pet foxes’ pet owner research results coupled with the lungworm prevalence fox studies highlights the growing concern of the spread of Angiostrongylus vasorum in the UK and the need for adequate preventative measures for pet dogs.

"Veterinary professionals are perfectly placed to advise dog owners on the risk of their pets becoming infected with the parasite, including the growing role of foxes as potential wild animal reservoirs of Angiostrongylus, as well as advising pet owners to use a monthly spot-on prevention such as Advocate.

"Treatment with products containing moxidectin, such as Advocate, not only kills lungworms present at the time of treatment but also kills larvae after ingestion preventing new infections. Regular monthly use prevents disease and ensures that no lungworm larvae are shed in dogs’ faeces which helps to prevent the spread of the parasite in the environment."

To highlight the increased prevalence of lungworm in foxes Bayer has created a poster for veterinary practices, which you can get from the Bayer Vet Centre at:


  1. YouGov Survey, May 2019, 2036 GB adults surveyed. All figures, unless otherwise stated, are from YouGov Plc.  Total sample size was 2036 adults. Fieldwork was undertaken between 20th - 21st May 2019.  The survey was carried out online. The figures have been weighted and are representative of all GB adults (aged 18+).
  2. Taylor et al. (2015) Parasitology 142:1190-5.
  3. Morgan et al. (2008) Veterinary Parasitology 154: 48–57.
  4. Fox et al. (2017) Proceedings of WAAVP, Abstract No. 4196, p.163.

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