Cercaria

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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 ?
The procedure was repeated until several cercariae were obtained from each species of snail.
In a study of Ribeiroia ondatrae, cercariae were consumed by Hydra spp.
9%) were infected with the trematode cercariae of O.
A single infected snail has the potential of shedding thousands of cercariae daily for many months.
In flukes temperature has a pronounced and direct effect on a crucial step of their life cycles such as the production of cercariae in the first (or unique) intermediate molluscan host in both aquatic life cycles (Kendall and McCullough1951; Dinnik and Dinnik 1964; Boray 1969; Ollerenshaw 1971; Nice and Wilson 1974; Tang et al.
Schistosoma mansoni: human skin ceramides are a chemical cue for host recognition of cercariae.
The cercariae are motile, and are phototropic and chemotropic, meaning they respond to changes in light and chemical stimuli--they are especially attracted by chemicals found on mammalian skin.
School-age children who live in these areas are often most at risk because they tend to spend time swimming or bathing in water containing infectious cercariae (larvae).
The cercariae are motile, and are phototropic and chemotropic, meaning they respond to changes in light and chemical stimuli they are especially attracted by chemicals found on mammalian skin.