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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Just in one mollusc can develop at the same time more than 100 trematodes' cercariae. This is confirmed by our own research, according to which, up to 11% of cattle in the territory of Kyiv and Zhytomyr regions are having fasciolosis.
In the laboratory, the snails were kept individually in vials with 20 mL of tap water, and were observed for the emergence of cercariae. Seemingly uninfected snails were dissected to check for other larval intramolluscan stages (e.g.
mansoni cercariae (experimental infection with LE, SJ, and AL, resp.); (2) during the prepatent period (11 days after experimental infection); and (3) noninfected (not exposed to infection).
magna infection (Swales 1936, Pybus 2001), some cercariae may encyst as free-floating metacercariae in surface water (Morley 2015).
However, even with a small infestation of the population, it may be sufficient to maintain opisthorchiasis foci, as opisthorchis larvae's parthenogenetic reproduction occurs in the shellfish body for a long time, resulting in the multiple increase in the numerosity and displacement forms of cercariae. In addition, the lifetime of bithyniidae is rather long, 4-6 years, which increases the foci stability additionally.
(2) After 4-6 weeks of infecting the snail, the cercariae leave the snail and gyrates around for about 72 h looking out for the skin of a prospective host.
Prevalence and epidemiology: The cercariae of liver flukes were observed from a pond first time by Otto Muller in 1773 (Andrews 1999).
Schistosomiasis is a rare cause of tubal disease that could result in ectopic pregnancy, infection occurs when the Schistosoma larvae (cercariae) penetrate the skin following their release by fresh water snails; after maturing into adult forms in the lungs; the latter get carried by the blood to the splanchnic or vesical veins.
gigantica as a result of the ingestion of metacercariae --formed by mature cercariae that emerge from the snail--and which are glued to aquatic vegetables.
We obtained cercariae from red-rim melania snail using the positive-phototaxis methods described by Lo and Lee (1996b) and Umadevi and Madhavi (1997).
Although the main role of cercariae of these parasites, which are components of zooplankton (meroplankton), being to find and infect the target host; secondarily, they play an important role in the trophic web of aquatic environments.