Cryptocotyle lingua (Creplin, 1825) Fischoeder, 1903

ETYMOLOGY:Crypto (hidden) + cotyle (disk) [for the small ventral sucker being incorporated, hidden within, the muscular a ring of small spines around the oral opening] and lingua for the tongue-like shape of the body.

SYNONYMS:Hallum caninum Wigdor, 1918.

HISTORY: This parasite was first described by Creplin in 1825 and placed by Fischoeder in the genus Cryptocotyle in 1903.

GEOGRAPHIC DISTRIBUTION: This parasite has been reported from North America (Burrows and Lillis, 1965), Europe, and Asia.

LOCATION IN HOST: Small intestine.

PARASITE IDENTIFICATION: This small worm (1.29 to 1.46 mm long by 0.59 to 0.77 wide) differs from Cryptocotyle concavum in that the body is more tongue-shaped.

The eggs are 34 to 38 µm long by 16 to 20 µm in width.

LIFE CYCLE: The typical final host are gulls and terns. The life cycle was examined by Stunkard (1930) and by Stunkard and Willey (1929) who experimentally infected cats. The snail hosts are the brackish-water and seawater snails Littorina littorea and Littorina rudis. The cercariae that are released encyst in cunner and other salt-water fishes. Cats become infected by eating the brackish-water fish. The worms rapidly grow to adults, producing patent infections in a week to twenty days.

CLINICAL PRESENTATION AND PATHOGENESIS: Although experimental infections in cats produced worm development between the intestinal villi, no clinical signs developed.

TREATMENT: Probably praziquantel, but not reported.

EPIZOOTIOLOGY: Cats, like the typical bird hosts, become infected by eating raw fish. Animals other than the cat that have been shown to serve as hosts of the adult fluke include the dog.

HAZARD TO OTHER ANIMALS: None. Although other hosts are infected, the major means of infection is through the ingestion of the fish intermediate host which requires that the appropriate snail also be available. Thus, infection of these other hosts will typically only occur in the wild.

HAZARD TO HUMANS: Humans could possibly be infected if they ingested the fish intermediate host.

CONTROL/PREVENTION: Prevention of the ingestion of raw fish.


s Burrow RB, Lillis WG. 1965. Trematodes of New Jersey dogs and cats. J. Parasitol 51:570-574.

Stunkard HW. 1930. Life history of Cryptocotylelingua (Crepl.) from the gull and tern. J Morph Physiol 50:143-191.

Stunkard HW, Willey CH. 1929. The development of Cryptocotyle (Heterophyideae) in its final host. Am J Trop Med 9:117-128.