An Oregon woman has become the first person worldwide known to have had an eye infestation by a tiny worm species previously seen only in cattle that is spread by flies that feed on eyeball lubrication, U.S. government researchers said on Monday.

U.S. Centers for Disease Control and Prevention scientists said 14 translucent parasitic worms of the species Thelazia gulosa, all less than half an inch (1.27 cm) long, were extracted from the 26-year-old woman's eye over a 20-day period before her symptoms dissipated.

This species of Thelazia worm was previously seen in cattle throughout the northern United States and southern Canada, the researchers reported in a study published in the American Journal of Tropical Medicine and Hygiene. They said the study indicates that North Americans may be more vulnerable than previously understood to such infections.