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Eye worm danger to dogs

Vets have warned UK dog owners that an infectious parasite increasingly common on the continent could soon pose a health risk to pets on British shores. Eye worm, also known as Thelazia callipaeda, was found last year (2016) in one dog imported from Romania and a further two that had recently travelled to Italy and France. So while the risk of your pet contracting eye worm remains very low, particularly if your dog has not travelled abroad or come from another country, it’s important to be aware of the symptoms and risks.

What is eye worm?

You may be able to see the worms on the eyeball.

Eye worm is a vectorborne disease carried by fruit flies, which are very common in the UK. It can infect a wide range of mammals including cats and humans but, at present, vets are most concerned about it spreading among the UK’s canine population due to a large number of dogs taken abroad by their owners on holiday.

Infection starts when a fruit fly carrying the parasite lands on the eye and lays infected larvae which feed on tears.

What are the symptoms?

  • Red and sore eyes (conjunctivitis)
  • Swollen eyes
  • Mucus around the eye
  • Excessive watering in the eyes
  • Eye ulcers
  • Visual impairment

However, some pets will show no symptoms. In some cases, you might be able to see the worm on the eye.

What countries is eye worm prevalent in?

The disease is infecting increasing numbers of dogs in France, Italy, Switzerland, Germany, Spain, Portugal, Bosnia, Herzegovina, Croatia, Romania, Bulgaria and Hungary. In some locations, including the Basilicata region of Italy, the infection has reached a hyperendemic stage, with more than 40 per cent of dogs contracting the condition. Generally speaking, the parasites are normally found in areas of oak woodland in warm conditions, with peak season being late summer/early autumn.

Can it be prevented?

Yes. Some products which are already given to pets to prevent other parasites can be effective in also preventing eye worm. Speak to your vet about this.

If travelling abroad, ensure all worming and flea treatment is up to date; that is also a requirement of the pet passport. However, all three dogs in the UK that have been affected were compliant with the UK government’s pet travel scheme (PETS) requirements. Therefore, the British Veterinary Association has urged pet owners to be particularly vigilant and look out for symptoms when travelling to an area known to be infected with the parasite to limit the chances of it spreading further. But do remember that thousands of dogs enjoy problem-free holidays on the continent with their owners each year.

How is eye worm treated?

The eyes will be cleaned, normally under anaesthetic or sedation, and any visible worms or larvae removed. Eye drops and antibiotics are then usually prescribed, which can clean up an infection within seven days.

What is the prognosis of eye worm?

If caught early and is treated in time, pets should make a full recovery with no lasting implications. But if left untreated, there is a risk of permanent blindness.

Can it be transmitted to humans?

In theory, yes, but this is very rare. Cases of infection spreading to people have been reported in Spain, Italy, France, Croatia and Serbia. But humans are presently thought to be at a very low risk of being infected, particularly if any dogs with conjunctivitis are promptly treated by a vet.

— Page last updated 22/09/2017