Also found in: Dictionary, Thesaurus, Medical, Wikipedia.


(invertebrate zoology)
The larval generation which terminates development of a digenetic trematode in the intermediate host.



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 ?
First, the infectivity of cercaria is known to be temperature dependent and is reflected in the model through the unit-free infectivity function [I.
The notion is that they will both equal unity if cercaria and miracidia are uniformly distributed in the surface water system, but both can be larger or smaller than unity.
Hence, we expect that the final definition of risk groups will be based on both infection data and spatial features, the latter related to the clear importance of surface water transport of cercaria and miracidia.
Cercaria [not released, measurements based on the 10 largest
According to Bartoli (1974), a gymnophallid cercaria can be identified by the following characteristics: Distome, pharyngeate larva, tegument spinose, eyespots absent, stylet lacking, excretory vesicle thin-walled V or Y shaped, furcated tail, developing in marine bivalves.
Thus, the fellodistomid cercaria observed in the present study likely belongs to the subfamily Baccigeriinae.
maculatus in LIS mussels was Uzmann (1953), who named them Cercaria milfordensis.
Cercaria tenuans, larval trematode parasite of Mytilus and its significance in mussel culture.
subtenuis (Linton, 1907; Hanson, 1960) and description of Cercaria adranocerca N.
The developed QCM immunoaggglutination system was applied to evaluate several unpurified IRS specimens with various degrees of Sj infection, denoted by the numbers of Sj cercarias (parasitic larvae) and days of infection.