Definition of miracidium in English:

miracidium

noun

Zoology
  • A free-swimming ciliated larval stage in which a parasitic fluke passes from the egg to its first host, typically a snail.

    • ‘Generally, host seeking by miracidia includes a complicated behavioral process that is initiated through a combination of light and gravity stimuli.’
    • ‘Not only do P. sinitsini become adults in E. symmetrica, but eggs are produced and hatch inside the daughter sporocysts, releasing free-swimming miracidia.’
    • ‘Larval stages of some medically important species include miracidium, redia, cercaria, and metacercaria.’
    • ‘By following this pathway, miracidia are immediately ready to infect other snails, thus by-passing two hosts in the parasite's life cycle, and creating the opportunity for direct, snail-to-snail transmission.’
    • ‘Whereas SmHox8, SmHox1, and Smox1 were all strongly expressed in eggs and miracidia compared to other stages, SmHox1 was much more weakly expressed in all the other stages.’

Origin

Late 19th century: from Greek meirakidion, diminutive of meirakion ‘boy, stripling’.

Pronunciation

miracidium

/ˌmʌɪrəˈsɪdɪəm/