Miracidium


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Related to Miracidium: sporocyst, cercariae, Metacercariae, rediae

miracidium

[‚mī·rə′sid·ē·əm]
(invertebrate zoology)
The ciliated first larva of a digenetic trematode; forms a sporocyst after penetrating intermediate host tissues.

Miracidium

 

the first larva in the development of trematodes, parasitic flatworms. The elongated body is 0.03 to 0.3 mm long and clad in large ciliated cells, which are usually distributed in four to six longitudinal rows. At the anterior of the body open the penetrative glands (a vestige of the intestine that has changed its primary function), whose secretions facilitate implantation of the miracidium in the body of the intermediate host. The organism’s nervous system is represented by the anterior medullary mass of nerve cells. The miracidia of many species have an X-shaped pigmented ocellus in front. The excretory organs are a pair of protonephridia. The body cavity contains germ cells. Miracidia usually emerge from the egg in water, swim for a time, and then implant themselves in the body of an intermediate host (usually a mollusk), where they are transformed into sporocysts.

References in periodicals archive ?
At the center of granulomas are eggs; some containing a developing miracidium and others are empty eggshells.
Adult worms release eggs that are shed in the bird's feces and upon immersion in water, a miracidium emerges.
During the survey, the Kato-Katz technique and the miracidium hatching test were used for fecal examination.
The miracidium within the eggs release proteolytic enzymes that damages the host tissue leading to passing of loose feces with large number of schistosoma ova (Soulsby, 1982).
The larval stage, known as miracidium, is hatched from the egg in the water and enters the snail host.
Miracidium The larve that emerges from the egg in trematodes.
Praziquantel only kills adult worms and does not inactivate schistosomules, nor the miracidium inside the eggs, which will continue to elicit a damaging immunologic response for some time.
by tranverse septa (56) N atrophy or oral sucker (57) N first larval stage a miracidium (58) La miracidium hatches from egg and swims to snail host