As reported by National Geographic last week, a 28-year-old woman named Abby Beckley experienced the first human case of parasitic cattle eye worm (Thelazia gulosa) in 2016 in Southern Oregon. Beckley had been living on a mostly unused former cattle ranch at the time of the infection.
Beckley originally believed that she had an eyelash poking under her eyelid. When she couldn’t find the lash, she took a closer look at the area. While pulling at the parts of her lid that were inflamed, she discovered to her horror a nearly transparent worm. After doctors from Oregon Health & Science University received confirmation of the species of eye worm from the Centers for Disease Control and Prevention, they were able to help Beckley remove and kill the remaining worms. Thankfully, the “worms” were actually only larvae and not yet mature members of the species that could produce new offspring. They also don’t typically burrow into eyeballs.
Beckley likely became infested with the cattle eye worms as a result of a face fly landing on her eye to drink her tears. Thelazia gulosa live inside of face flies during their larvae state. They are then passed onto cattle and other animals as the flies quench their thirst. Beckley removed 14 eye worms before the end of her treatment.
This incident serves as a chilling warning about flies and hygiene. Although many people in the United States believe that mosquitoes and ticks are the primary insects that pose the greatest threats to human health as disease carriers, different types of flies carry organisms that they deposit on surfaces that they touch. People should do everything possible to keep indoor and outdoor flies away from them. It’s also important to wash or flush, as in the case with eyes, any areas touched by flies immediately after exposure. The World Health Organization has named flies a “vector” of disease and a sanitation risk because they feed and breed near filth and waste and the organisms inside of them can continue to live for days after they die.