Case study: The man with the worm in his eye

When a live worm burrowed into the eye of a 25-year-old man, he required surgery that eventually helped him regain vision.

Dave Yasvinski 3 minute read February 12, 2021

Each week we comb through science journals to explore a baffling medical issue.

Whoever said a little hard work never hurt anyone is clearly unfamiliar with the lovely little larvae that causes African eye worm.

A 25-year-old man living in India got up to speed in a hurry after doctors discovered a “long, live worm” had burrowed into his left eye. Researchers documenting the bizarre experience for BMJ Case Reports in 2015 believed his job put him at heightened risk of acquiring the parasite caused by the bite of an infected mangrove fly.

The flies, more commonly found far from India in the rainforests of Africa, leave behind a type of roundworm called Loa loa (or worm worm) that can develop into an infection known as Loiasis (or African eye worm). “His occupation as a fruit vendor may have increased his risk for infection, as fruit flies may carry the parasite,” said Bhagabat Nayak, co-author of the case study and an ophthalmologist and eye surgeon at the Dr. R.P. Centre for Ophthalmic Sciences in New Delhi, India, according to Live Science.

The man soon sought medical attention complaining of floaters, threads and clouds moving across his field of vision. His left eye was red and painful and he said his vision had been impaired for two weeks. The case study said the worm, which was causing the blurred vision, was visible during inspection. “On examination, the anterior segment revealed moderate inflammation,” the report said. “Posterior segment examination showed a grade one vitreous haze with a fairly long live worm moving around in a haphazard and relentless manner throughout the vitreous cavity.”

It was the first time African eye worm had been reported in that area of the eye, leading investigators to speculate the worm may have made the journey through the blood vessels or tissue layers of the eye while still in rambunctious larvae form before maturing to adulthood in its new home. Many people who experience African eye worm have no symptoms or symptoms that only present months after infection, according to the Centers for Disease Control and Prevention. If they do appear, tell-tale signs include itchy, non-painful swellings anywhere in the body — though mostly near joints — that appear and disappear without warning. The most jarring symptom of all, however, is likely watching a worm wiggle across one’s eyeball or slowly slither beneath the surface of the skin. Less common indications of the disease include muscle pain or fatigue.

Doctors, concerned the drugs available to kill the worm might permanently damage the man’s vision, opted for surgery to remove the slimy stowaway. Once it was evicted, microbiologists were able to confirm the team’s suspicions. “We planned the patient for vitrectomy and removal of the worm was performed under steroid cover,” the report said. “The worm was sent to the microbiology department for examination and it was found to be the species of Loa loa. The patient was administered a course of diethylcarbamazine and, on follow-up after two weeks, his vision had improved to 20/40.”

This particular type of eye worm had not been encountered by any of the attending physicians although they were familiar with the work of other eye parasites. The species, which thrives during rainy season, is uncommon in India. A couple of weeks after successful surgery, the produce peddler said his vision had vastly improved and the floaters had disappeared.

No word on whether he is taking precautions to ensure his line of work doesn’t leave him as an option on the menu.

Dave Yasvinski is a writer



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