An unwelcome companion to man’s best friend

Researchers have reported three cases of a parasitic eye worm in UK dogs that have recently returned from mainland Europe.

As part of an article published in Veterinary Record, the study authors encourage vets to be vigilant when examining dogs that have travelled abroad with their owners.

“Although effective diagnostic tests and treatments are available, more can and should be done to prevent this zoonotic pathogen from becoming endemic in the UK,” they write.

The parasitic worm, thelazia callipaeda, is spread by a fruit fly and is capable of infecting dogs, cats and human beings.

Lead author and University of Liverpool postdoctoral research associate, Dr John Graham-Brown, told OT  that cases of the parasite in humans were reported in Spain, Italy, France, Croatia and Serbia.

“As far as we are aware transmission is not occurring in the UK itself, and the risk to animals and people is currently through travel abroad,” he highlighted.

Clinical signs of the parasite in dogs included conjunctivitis, epiphora and in some cases corneal ulceration.

Dr Graham-Brown explained that while the adult parasitic worms were large enough to see, with a length of between 1-2cm, they were sometimes hidden in the conjunctival fornices and nictitating membranes of the animals.

“In dogs, infection is often only identified following flushing of the usually ventral fornix with sterile staline,” he shared.

Dr Graham-Brown encouraged dog owners to seek veterinary advice before travelling abroad to check whether their holiday destination was an area where transmission of the parasite is occurring.

AOP clinical and regulatory officer, Farah Gatrad, told OT  that cases of thelazia callipaeda are rare in people and they are unable to directly contract the parasite from their pets.

“However, thelazia callipaeda can cause a variety of complications that can present in moderate to quite serious symptoms in the eye including, conjunctivitis, excessive watering, visual impairment, and ulcers or scarring of the cornea,” she highlighted.

“Our advice to patients if they are experiencing symptoms, and especially if they and their pet have recently visited a country where there has been an epidemic, is to seek medical attention,” Ms Gatrad concluded.

Image credit: John Graham-Brown