Health and Medicine

Woman Runs Through Swarm Of Flies, Ends Up With Parasitic Worm Reproducing In Her Eyes


James Felton

Senior Staff Writer

clockNov 5 2019, 14:40 UTC

Hookworms close up. CDC / Wikimedia Commons

A 68-year-old woman from Nebraska started to feel an irritation in her right eye back in March 2018. Upon flushing it with tap water, she found she had dislodged a moving roundworm about half an inch (1.3 centimeters) in length.


Looking closer at her eye, she noticed a second moving worm, which she also removed by flushing it with water. She went to see an ophthalmologist the following day, and a third worm was found within her eye and removed. It seems there was quite the party going on in there. The ophthalmologist advised the patient – who was staying in Monterey County, California, at the time – to continue to flush the eye with water and manually extract the worms whenever she found them. Just the advice you want to hear.

The patient, who doctors wrote about in the journal Clinical Infectious Diseaseswas also given ointment to prevent bacterial infection and sent away. However, after returning home to Nebraska, she continued to feel irritation and a "foreign body sensation" in both of her eyes and once again sought medical advice. After removing a fourth worm and continuing a new course of treatment, she eventually was worm-free.

So far, so gross. What's really horrifying about this case, however, is how she got the worms in the first place. She may have picked up the parasites after she merely ran through a cloud of flies.

"The patient is a trail runner and recalls in early February 2018, rounding a corner on a steep trail in a Carmel Valley regional park and running into a swarm of small flies," the authors write in the case report.


"She recalls swatting the flies from her face and spitting them out of her mouth".

A sample of the worms sent for analysis was identified as Thelazia gulosa (cattle eyeworm).

"The worm was identified as an adult female T. gulosa," the authors write. Worse: "Eggs containing developed larvae were observed in utero, indicating that humans are suitable hosts for the reproduction of T. gulosa."


This is only the second time that the parasite has been found in humans, the authors from the Centers for Disease Control and Prevention's parasitic division write in the report. The first case was reported in February 2018, involving a woman who pulled 12 of the parasites from her eye. 

The authors are unsure why the species is now infecting humans, as it's normally transmitted between cattle by flies. They speculate it could be due to an increasing prevalence of the parasite in domestic cattle.

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