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(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 It might be outdated or ideologically biased.



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 ?
Measurements given in the description of each cercaria are based on heat-killed and formalin-fixed specimens and expressed in micrometers (qm), with range followed by the mean [+ or -] SD in parentheses.
El presente trabajo tuvo como objetivo identificar las especies de trematodos digeneos patogenos para alevines de tilapia, asi como los moluscos hospedadores de dichos parasitos; ademas, determinar las especies de moluscos presentes en estanques de cultivo de tilapia y los morfotipos de cercarias presentes en los moluscos.
Ademas, como repelente contra picaduras de insectos y cobras, se le considera como larvicida de mosquitos y con actividad cercaricidal contra las cercarias de Schistosoma mansoni Sambon (Trematoda).
Lo anterior corrobora la importancia de estas enfermedades en la produccion de rebanos ubicados en zonas cuyas condiciones ambientales favorecen el desarrollo y crecimiento de los estadios de vida libre (miracidios, cercarias, metacercarias) y del hospedador intermediario (en el caso de trematodos) [17,31], y de larvas en desarrollo e infectantes (en el caso de nematodos) [4,18,28].
Especies de estas familias son hospederas intermediarias de trematodos de la familia Schistosomatidae, cuyas cercarias producen el mismo tipo de dermatitis descrita para las especies de la familia Chilinidae (Ostrowski de Nunez 1992).
El contagio de esta enfermedad tiene lugar en la mayoria de los casos por la ingestion de hierbas contaminadas con quistes de cercarias (metacercarias).
Quiniou et al., "Genetic sequence data identifies the cercaria of Drepanocephalus spathans (Digenea: Echinostomatidae), a parasite of the double-crested cormorant (Phalacrocorax auritus), with notes on its pathology in juvenile channel catfish (Ictalurus punctatus)," Journal of Parasitology, vol.