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''Philophthalmus gralli'', commonly known as oriental avian eye fluke, is found in conjunctiva sac of eyes of many species of birds. The oriental eye fluke is described to parasitize the conjunctiva sac of various galliforms and anseriforms (Nollen and Murray 1978). In Brazil this parasite was reported in native anseriforms species (Muniz-Pereira and Amato 1993). It was first discovered by Mathis and Leger in 1910 in domestic chickens from Hanoi, Vietnam.〔Mathis, C. and Leger, M. 1910. Douve oculaire de la poule. ''Bulletin Societe Pathologie Exotique'' 3: 245–251.〕 Birds are definitive hosts and freshwater snail species are intermediate hosts (e.g. ''Tarebia granifera'' and ''Melanoides tuberculata''.)〔Mukaratirwa, S., Hove, T., Cindzi, Z. M., Maononga, D. B., Taruvinga, M. & MATENGA, E. 2005. First report of a field outbreak of the oriental eye-fluke, Philophthalmus gralli, in commercially reared ostriches (''Struthio camelus'') in Zimbabwe. ''Onderstepoort Journal of Veterinary Research'' 72: 203–206.〕 Human cases of philophthalmosis are rare, but have been previously reported in Europe, Asia, and America (i.e., Yugoslavia, Sri Lanka, Japan, Israel, Mexico, and the United States). ==Life cycle== Philophthalmus gralli reaches sexual maturity in a bird and produces eggs. Fully embryonated eggs are shed into the water from the definitive host’s eyes. Miracidium is induced to hatch when ripe eggs are released from the worm into water. Upon contact with a snail, the miracidium perforates the host epidermis with the aid of secretions and the anterior cilia. It penetrates the snail far enough to release a single rediae. The mother redia localizes in the heart and produces daughter rediae, which migrate to digestive glands to continue its development and produce megalurous cercariae. Cercariae are released from the snail and encyst on aquatic vegetation or other solid objects in the water. The definitive host, which is usually an aquatic bird, becomes infected upon ingestion of metacercariae. Excystment of the metacercariae occurs immediately upon reaching the mouth or crop of the bird and not in the stomach or intestine as in many other digenetic trematodes. Within 3 to 5 hours after ingestion, immature worms may be found in the esophagus, nasal passages, the orbit and the lobes of the lacrimal gland. Humans rarely serve as incidental hosts, but may do so when they ingest metacercariae on aquatic vegetation. 〔West, A. 1961. Studies on the Biology of Philophthalmus gralli Mathis and Leger. ''American Midland Naturalist'' 66: 363-384〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Philophthalmus gralli」の詳細全文を読む スポンサード リンク
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