(species Loa loa), common parasite of humans and other primates in central and western Africa, a member of the class Nematoda (phylum Aschelminthes). It is transmitted to humans by the deerfly, Chrysops (the intermediate host), which feeds on primate blood. When the fly alights on a human victim, the worm larva drops onto the new host's skin and burrows underneath. The larva migrates through the bloodstream, commonly locating in the eye or in other tissues just under the skin. The adult worm is about 5 cm (2 inches) long. The movement of the worm beneath the skin may cause itching or sometimes swellings as large as a hen's egg
Learn more about eye worm with a free trial on Britannica.com.