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Life cycle of Philophthalmus trematode flatworms (eye flukes)

Image of <i>Philophthalmus palpebrarum</i> Looss 1899

Description:

Life cycle of Philophthalmus trematode flatworms (eye flukes)

Fully-embryonated Philophthalmus eggs are shed into the water from the definitive host’s eyes (1). Miracidia hatch almost immediately in water (2) and penetrate the snail intermediate host (3). Several snail genera may serve as intermediate hosts, including Thiara spp. and Melanoides spp. Inside the snail host, the miracidia (which contain a pre-formed redia) undergo a series of stages (3a, 3b) and become cercariae. Cercaria are released from the snail (4) and encyst on aquatic vegetation or other solid objects in the water (5). The definitive host, which is usually an aquatic bird, becomes infected upon ingestion of metacercariae (6). Metacercariae excyst in the mouth and migrate to the eye where the adults reside (7). Humans rarely serve as incidental hosts, but may do so when they ingest metacercariae on aquatic vegetation (8).

From Centers for Disease Control Parasites and Health website.

Source Information

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cc-by-nc
copyright
Centers for Disease Control/Division of Parasitic Diseases and Malaria
publisher
Shapiro, Leo
photographer
Centers for Disease Control/Division of Parasitic Diseases and Malaria
provider
EOL Rapid Response Team
original
original media file
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partner site
EOL staff
ID
17764121