Biology 625
Supplemental visual material

Eggs and proglottids of Diphyllobothrium latum (Broad fish tapeworm)
(Cestoda, Pseudophyllidea)

Definitive hosts: this species infects a wide variety of fish eating mammals, including humans
Site of infection: small intestine
Typical size: up to 10 meters in length
Distribution: cosmopolitan
First intermediate host: Copepods ingest the coracidia that hatch from the operculated eggs. Procercoids develop in the hemocoel
Second intermediate host: multiple species of freshwater fish, especially salmonids. Pleurocercoids develop in the muscles and viscera. Paratenic hosts are common and help bridge the ascension of the parasite from copepods to predatory fish.
proglottids (above); note rosette-like uterus which is filled with eggs
typical eggs from feces; note "knob" at posterior pole


Originals; photographs by S.J. Upton

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Kansas State University | Biology Division