Two studies have published their findings in The American Journal of Tropical Medicine and Hygiene, with one revealing that a woman in the U.S. state of OR is the first known instance in the world of a human infection with Thelazia gulosa.
It means that North Americans may actually be more vulnerable than previously thought to such infections.
"We never expected to see this particular species in a human", Bradbury said. The flies ingest the worm larvae, then land on an animal's eyes, where the flies feed on tears and other secretions.
Beckley had been horseback riding and fishing in Gold Beach, Ore., a coastal, cattle-farming area.
Beckley said she doesn't remember if a fly landed near her eye. Although the OR woman went to the doctor for treatment, she's managed to remove most of the worms on her own.
She said she kept pulling worms out of her eye at home, and was anxious they would attack her brain.
Dr Erin Bonura, from the OHSU School of Medicine explained: 'It's a little unsatisfying to ask the patient to just keep pulling out the worms, but that is the best thing to do because if we give her an antiparasitic agent, the worms would die in there but wouldn't be removed'.More news: Israel, Iran and the war for Syria
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Medical professionals removed more and more worms over the next 20 days, until Beckley's symptoms disappeared.
Eye worms infect a variety of animals, but human infections are rare.
"Cases of eye worm parasitic infections are rare in the United States, and this case turned out to be a species of the Thelazia that had never been reported in humans", said lead author Richard Bradbury, from the CDC's Division of Parasitic Diseases and Malaria. "She's okay. I can be okay too". Adult female face flies typically cluster around the host's eyes, mouth, and muzzle, causing extreme annoyance. "They had to remove them as they became present and visible".
"I stayed in contact with her, and we were able to tell her this was very localised, that it was not systemic", the physician said.
According to the Centers for Disease Control and Prevention, Beckley had a type of eye worm called Thelazia gulosa.
Meanwhile, another species of eye worm - Thelazia callipaeda - is reportedly spreading from Asia to Europe and is also transmitted by a common fruit fly, Phortica variegata.
A WOMAN has become the first person in the world to have her eyes infested with a parasitic WORM usually found in cattle and dogs. In the worst-case scenario, they can cause scarring of the cornea and even blindness, researchers say.