A 68-year-old woman on a trail run in Carmel Valley on the Northern California coast didn’t think much of it after encountering a swarm of flies in 2018, ScienceAlert reports.
A short time later, however, her eyes felt irritated, and the woman wound up flushing out a half-inch parasitic roundworm from her eye, LiveScience reported. She removed a second roundworm, and an eye doctor in Monterey found a third.
After returning home to Nebraska following the gruesome March 2018 discoveries, the woman still felt discomfort and later removed a fourth roundworm from her eye, according to the publication.
The incident is only the second-known case of eye infestation in humans by Thelazia gulosa in the United States, a study published Oct. 22 in the Clinical Infectious Diseases journal says.
Eye infections by roundworms are more commonly seen in cattle, the Centers for Disease Control and Prevention reports.
Infected flies normally deposit roundworm larvae in the eyes of cattle while feeding on tears, according to the CDC. The larva infest the eyes, where they grow to adulthood and can cause inflammation or other ailments — including blindness.
“It felt like when an eyelash is poking you,” said Abby Beckley, the first known human to suffer an eye infection by roundworms, National Geographic reported.
After five days of irritation while fishing in Alaska in 2016, Beckley became determined to resolve the problem, according to the publication.
“So one morning, I woke up and I was like, If it’s the last thing I do, I’m going to get whatever the heck is in my eye out of there,” she said, National Geographic reported. She ended up pulling five roundworms from her eyes before she could reach a doctor.
“I was just pulling them out, so I knew there were a lot,” Beckley said, according to the publication, adding the doctors were “legitimately freaked out.”
The Clinical Infectious Diseases study, written by CDC scientists, says it’s unclear why humans are only now being infected by roundworms, which have been a problem in cattle since at least the 1940s, LiveScience reported.
The study says the two cases “suggest that this may represent an emerging zoonotic disease in the United States,” according to the publication.
“Importantly, eggs containing developed larvae were observed in utero, indicating that humans are suitable hosts for the reproduction of T. gulosa,” the study says, ScienceAlert reported.