A Second Woman Pulls Parasitic Eye Worms out of Her Eye, and Doctors Fear It’s Just the Beginning


My husband likes to watch shows like Monsters Inside Me, and let me tell you – I’ve never been as paranoid to climb in a lake or take a hike in the tropics as I am after living with him for six years.

And this species of worm that infects human eyes seems like it would be as at home on that show as it is wriggling around in people’s corneas.


A case was recently documented in an issue of Clinical Infectious Diseases. The patient involved was a 68-year-old women from Nebraska who had recently run into a swarm of flies while jogging in California. It didn’t take doctors long to realize the flies must have been Musca autumnalis (face flies), because a month later, her eyes were itching, irritated…and housing parasites. Explains lead author Richard Bradbury,

“The vector fly will expel larvae onto the surface of the eye or the conjunctiva while feeding on lacrimal secretions (tears, etc). This can happen very quickly, so the fly would not have had to sit on the eye for more than a few seconds to expel the larvae. Normally people would shoo any flies near their eyes away before they could do this, but in this case the patient had run into so many flies at once that she could not shoo them all away before one expelled larvae onto her eye.”

She washed out the first worm with tap water, then found and took care of a second one a few days later. A day after that, she went to an ophthalmologist, who found a third one. She returned home, thinking all was well, but a few weeks later and still in discomfort, she found a fourth – and final – hitchhiker.

Bradbury and his team studied the worms and discovered they were members of Thelazia gulosa, or the cattle eye worm. Not only that, but the one they examined was an adult female with a cache of larvae-filled eggs of her own, which means (horrifyingly) that our eyes are perfect breeding grounds.

But the Nebraskan woman was actually the second known case.

In 2016, an Oregonian woman had 14 cattle eye worms extracted – she was the first known case – and Bradbury notes that while the women were both lucky to suffer no after-effects, cattle are usually left with damaged or blind eyes.


The emergence of two cases so close together suggests to doctors and researchers this could become a trend, according to Bradbury.

“While it may just be a fluke event that two cases have occurred within a year or two of each other, it does raise the possibility that something might have changed in the ecology of T. gulosa in the USA to cause it to start occasionally infecting humans.”

It’s possible that there has been an increase in the files and that their preferred habitat is widening, meaning that more animals populations in the country – and therefore, more humans – are being exposed. Bradbury thinks the next step is to study those animal populations and see if we can detect significant changes in face fly spread.


“It is also really important that anyone who thinks they might have worms in their eyes should go and see a qualified medical doctor for help. The doctor can arrange to send any worms recovered from the eye to a parasitology reference laboratory for identification to see if they are T. gulosa. This way, we can know if any more human infections like this happen.”

I don’t know about y’all, but I’ll be perfectly happy to never hear about this story every again.