Continuing our theme of nasty places to have worms, how about under the eyelid?! Flukes of the genus Philophthalmus are found in the conjunctival sac of the eyes of many species of birds and rarely in humans. In this case, a rhea (Rhea americana) in a zoo had an unusually heavy infection of several hundred flukes in each eye. The intermediate hosts are aquatic snails. When the cercariae escape from the snail, they encyst on vegetation or occasionally at the surface of the water and the cysts are ingested by the final host, where they hatch and migrate to the eye.
Contributed by Mike Kinsella, photo by Melanie Church.