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 ?
Scanning electron micrographs of Furcocercaria V 14: dorsal view of cercarial body showing arrangement of sensory button papillae and spines on tegument; 15: ventral view of cercarial body showing arrangement of sensory button papillae and spines on tegument; 16: detail of rows of spines on the anterior organ; 17: ventral sucker with 5 circles of spines surrounding its opening and sensory button papillae above it; 18: detail of spines and sensory button papillae on body.
Epidemiology of cercarial stage of trematodes in freshwater snails from Chiang Mai province, Thailand.
Photocycle- dependent emergence by cercariae of Halipegus occidualis from Helisoma anceps with special reference to cercarial emergence patterns as adaptations for transmission.
Cercarial dermatitis outbreak at a state park - Delaware, 1991.
TABLE The differential for a pruritic, erythematous maculopapular rash (5,7) Condition Characteristics Cercarial dermatitis A maculopapular inflammation characterized by pain, prickling, and pruritus that develops several hours after bathing in freshwater and is limited to exposed areas of the body.
Eggs appear in stool or urine (1) to 3 months after cercarial penetration (1).
The cercarial protein extract (CE) was achieved solubilizing the lyophilized cercariae in 7M Urea, 2M Thiourea, 4% CHAPS, 20 mM Tris pH 8, 65 mM DTT (IEF buffer).
Goodman reported the presence of 24 different cercarial species from four species of snails.
As with studies examining the effects of heavy metals on cercarial swimming ability (e.
The snails were then removed from the aquarium, the cercarial suspension was gently mixed and one hundred microliter of the suspension were [+ or -] 10 S.
Seasonal discrepancies in fluke infection rates and parasite loads were insignificant, though sporadic cercarial exposure in young raccoons and small sample size may have obscured seasonal trends.