It's fairly common in Argentina in cattle (also in Brazil). Time for a gruesome anecdote! My dad is a retired ophthalmologist (eye doctor), he used to do resi

It's fairly common in Argentina in cattle (also in Brazil). Time for a gruesome anecdote! My dad is a retired ophthalmologist (eye doctor), he used to do residences in a public hospital specialized on eyes for the Greater Buenos Aires area (several million people nearby, so you see all kinds of weird crap). Once I asked him what was the nastiest case he had attended and he told me it was one of a drunk guy that passed out and slept with his eyes not fully closed. While asleep the flies laid eggs on the eyeball, he waited too long to go to a hospital and my dad had to take the worms one by one from the poor dude's eyes. He survived but lost both eyes. Normally is mostly dangerous only to animals, there are sprays you can put on a wound that will kill the larvae and help the animal heal.