Pseudophyllidea

Pseudophyllidea is a tapeworm order within the class Cestoda. These parasites are characterized by their broad, flat bodies and the presence of a uterine pore in addition to the genital pore on the ventral surface of the proglottis. The scolex, or head, typically possesses both bothria, which are shallow grooves, rather than suckers for attachment.

The life cycle of Pseudophyllidea typically involves two intermediate hosts and one definitive host. The eggs are released into the water from the definitive host, usually a vertebrate. Miracidia hatch from the eggs and are ingested by the first intermediate host, often a copepod crustacean. Within the copepod, the miracidium develops into a procercoid larva. This infected copepod is then consumed by a second intermediate host, which can be a fish or other aquatic vertebrate. In this second host, the procercoid develops into a plerocercoid larva. When the definitive host ingests raw or undercooked flesh containing the plerocercoid, the tapeworm matures in its intestine.

Species within Pseudophyllidea are found in a wide range of vertebrate definitive hosts, including fish, birds, and mammals. Some species can cause significant disease in humans, such as Diphyllobothrium latum, the broad fish tapeworm, which can lead to vitamin B12 deficiency and anemia. Control measures often focus on proper cooking of fish and preventing fecal contamination of water bodies.