Question

Which one of the following life cycle stages of Liver fluke is infectious to the intermediate host ?

• A. Miracidi
• B. Cercaria
• C. Metacercaria
• D. Sporocyst

Answer 1

The correct option is A Miracidi

Infective stage of the intermediate host

The eggs released by the adult Liver fluke in the sheep give rise to miracidium (infective stage) that enters the snail (intermediate host).

The miracidium $\left(1^{st}\text{larva}\right)$ undergoes changes in the snail.

It changes to a sporocyst $\left(2^{st}\text{larva}\right)$ then rediae $\left(3^{st}\text{larvae by parthenogenesis}\right)$.

Rediae then produces the $\left(4^{st}\text{larvae}\right)$, i.e., cercariae by paedogenesis.

Final answer

(b) Miracidi