Cercaria

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Related to cercariae: schistosomiasis, Schistosoma, Metacercariae, rediae

cercaria

[sər′kar·ē·ə]
(invertebrate zoology)
The larval generation which terminates development of a digenetic trematode in the intermediate host.

Cercaria

 

the larva of parasitic worms of the class Trematoda. The body, which measures 0.3–1 mm in length, has an oral and a ventral sucker. Cercariae have a furcately branched intestine, a nervous system, sometimes ocelli, cephalic glands, and well-developed protonephridia. Typical of cercariae is the development of a tail, which is sometimes bifurcate (in furcocercariae) or equipped with lateral appendages.

The cercaria develops inside the preceding larval form, the sporocyst or redia, as a result of parthenogenesis. It leaves the body of the first intermediate host, a mollusk, and swims in water by means of its tail. It then penetrates the body of the second intermediate host, an invertebrate or frequently a fish, and becomes a metacercaria. The common liver fluke has no second intermediate host; the cercaria becomes encysted on coastal vegetation and is transformed into the next larval form, adolescarium.

References in periodicals archive ?
Comparison of cysteine peptidase activities in Trichobilharzia regenti and Schistosoma mansoni cercariae.
Inducible nitric oxide synthase-deficient mice develop enhanced type 1 cytokine-associated cellular and humoral immune response after vaccination with attenuated Schistosoma mansoni cercariae but display partially reduced resistance.
Putative aporocotylid cercariae from freshwater snails need further taxonomic attention and may represent a phylogenetically unique lineage.
Cercariae and metacercariae were identified to the level of morphotype (e.
Cercariae were shed from laboratory-bred infected snails (Biomphalaria alexandrina) 25-30 days after exposure to miracidiae.
After leaving snails, cercariae penetrate and encyst in tadpoles of the genera Lithobates, Hyla and Pseudacris, which, when fed to snakes of the genus Nerodia, adult flukes occurred in the mouth and esophagus of definitive hosts 35 days later (Byrd 1935; Walker 1939; Schell 1985).