The screwworm fly, Cochliomyia hominivorax.
Credit: Iowa State University
The scratching sound that Rochelle Harris kept hearing was all in her head — literally.
After the British tourist returned from a vacation in Peru earlier this year, she started experiencing headaches, shooting pains down the side of her face and an unexplained discharge from one ear.
Those symptoms, plus the bizarre scratching sounds she continued hearing, prompted Harris to visit a doctor soon after her return to England.
Though doctors at first dismissed the symptoms as nothing more than an ear infection, specialists soon made a startling discovery: Harris' ear was filled with flesh-eating worms, according to the Daily Mail.
The worms that Harris, 27, was hosting were the larvae of the New World screwworm fly (Cochliomyia hominivorax). The fly is a notorious livestock pest that also seeks out pets, zoo animals and occasionally humans as hosts.
A pregnant female screwworm fly seeks an open wound on the skin of a warm-blooded animal to lay her eggs. Within 24 hours, the eggs hatch into tiny larvae that feed on living tissue and bodily fluids, according to the Food and Agriculture Organization of the United Nations.
The screwworm fly was, after many years of eradication efforts, eliminated from the United States in 1959 by a program that introduced sterile males into the population. The fly, however, continues to plague livestock in parts of Central and South America.
A close relative, the secondary screwworm fly (Cochliomyia macellaria), feeds on dead or diseased flesh. The larvae of this fly have been used successfully in "maggot therapy" to clean infected wounds and promote healing after surgery.
Harris was apparently infected after a swarm of flies pestered her while hiking in Peru; one flew into her ear, but after she shooed the insect away, she thought nothing more of it.
Surgeons succeeded in removing what they called a "writhing mass of maggots" from Harris' ear, the Daily Mail reports. Though a tiny hole had been chewed into her ear canal, Harris suffered no serious damage from her ordeal.
In fact, there may be one positive development from her infection: "I'm no longer as squeamish as I was about bugs," Harris told the Daily Mail. "How can you be when they've been inside your head?"