Abstract.

We report a case of thelaziasis in a 26-year-old female, acquired in Oregon. A total of 14 worms were removed from the patient’s left eye and were morphologically identified as being Thelazia gulosa. Until now, only two species of Thelazia have been implicated in causing human disease, Thelazia callipaeda in Asia and Europe and occasional reports of Thelazia californiensis from the United States of America. Here, we describe a third, previously unreported parasite of humans, T. gulosa (the cattle eyeworm) as an agent of human thelaziasis and the first reported case of human thelaziasis in North America in over two decades.