Last updated February 15, 2018 at 11:04 am
The Oregon case is the first known infection by a parasite usually found in cows.
Thelazia gulosa on the surface of the patient’s conjunctiva (circled). Credit: John Hoyt
A woman from Oregon has become the first person in the world to have been infected by Thelazia gulosa, an eye worm that until now has only ever been found in cows.
Yep, eye worms – they’re a thing.
According to the United States Centers for Disease Control and Prevention (CDC), the woman felt an irritation in her left eye. About a week later, she pulled out a small, translucent worm.
Like some horror film, she ended up having 14 worms removed from her conjunctiva and the surface of her eye – all less than one and a half centimetres long. They were either plucked out with small tweezers, or flushed out with liquid.
The worms are usually spread by flies that feed on the tears that lubricate eyeballs. Doctors think the woman was infected by the flies while horseback riding and fishing in a coastal area of Oregon, a cattle farming region.
Adult female immediately after removal from the eye. Credit: CDC
Copping an eyeful
Tiny eye worms, whose whole family are called Thelazia, are usually found in a variety of animals – including cats, dogs, and wild carnivores like foxes, as well as cows.
They’re not often found in humans, and it was thought that only two species of Thelazia could infect humans at all, however, now a third needs to be added to the list.
Most people who get infected have inflammation and the sensation that there is something in the eye, which usually goes away after the worms are removed.
However, occasionally the worms will wriggle across the surface of the eye, causing scarring of the cornea and even blindness.
Human infections with eye worms are most common in the elderly or in young children, which makes sense as both patient groups may be less able to keep flies away from their faces.
The study was published in the American Journal of Tropical Medicine and Hygiene
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