An Oregon woman who had worms coming out of her eye is believed to be the first known human case of a parasitic infection spread by flies.

Key points: Abby Beckley pulls 14 worms from eye

Abby Beckley pulls 14 worms from eye She had been horseback riding and fishing at a coastal cattle farming area

She had been horseback riding and fishing at a coastal cattle farming area Eye worms are seen in animals like cats, dogs and cattle, but not humans

Fourteen tiny worms were removed from the left eye of the 26-year-old woman in August 2016. Scientists reported the case on Monday (local time).

Abby Beckley was diagnosed in August 2016 with Thelazia gulosa.

That's a type of eye worm seen in cattle in the northern United States and southern Canada, but never before in humans.

They are spread by a type of fly known as "face flies". Scientists said the flies feed on the tears that lubricate the eyeball.

She had been horseback riding and fishing in Gold Beach, Oregon, a coastal cattle farming area.

After a week of eye irritation, Ms Beckley pulled a worm from her eye.

She visited doctors, but removed most of the additional worms herself during the following few weeks.

Fourteen worms were removed from Abby Beckley's eye after she visited a coastal cattle farming area. ( AP: Centres for Disease Control and Prevention )

The worms were translucent and each less than half an inch long.

After they were removed, no more worms were found and she had no additional symptoms.

Eye worms are seen in several kinds of animals, including cats and dogs. They can be spread by different kinds of flies.

Two other types of Thelazia eye worm infections had been seen in people before, but never this kind, according to the study's lead author, Richard Bradbury, of the Centres for Disease Control and Prevention.

The report was published in the American Journal of Tropical Medicine and Hygiene.

AP