Common name. Oriental eyeworm
Geographic distribution. India, Burma, China, Korea, Japan, Russia, etc.
Infection rate. Thelaziasis is thought to be sporadically occurring throughout the world.
Life cycle. The adult worm is parasitic in the conjunctival sac of a final host, and it liberates viviparous larvae. These larvae are equivalent to the 1st stage larva. When they are swallowed by fly, They take off the sheaths in the digestive tract, go through the wall, invade the ovary or testis, where They become thin, 2-2.5 mm long 3rd stage larvae after two molts. They are the infective larvae. When the fly lick tears in the eyes of a final host, the larvae enter the conjunctival sac, and become adults in a month after two molts. The final hosts are mainly dogs and cats, and occasionally rabbits, monkeys, foxes, and humans. The intermediate hosts are insects. In Japan, species of Genus Amiota have been identified.
Morphology. The adult is thin and long. The female is about 15 mm long with thin both ends. The male is about 10 mm long, with a curled tail. In female, the vagina opens at the vulva located little behind the center of the esophagus on the ventral side.
Pathology and clinical symptoms. In case of human infection, it is generally noticed by severe foreign body sensation in early stage. In dogs and cats, however, chronic conjucntivitis induces photophobia, corneal opacity, or ulcer of the cornea.
Diagnosis & Treatment. Detection and removal of the worm.