Question

In the life cycle of the intestinal trematodes, fasciolopsis/fasciola and heterophyes, which of the following is known to infect snails?

A) Miracidia
B) Cercariae
C) Metacercariae
D) Sporocysts

Answer 1

In the life cycle of intestinal trematodes like Fasciola and Heterophyes, miracidia infect snails, developing further into cercariae that leave the snail to infect a new host.

Step-by-step explanation:

In the life cycle of intestinal trematodes such as Fasciola and Heterophyes, it is the miracidia that are known to infect snails. The infected human hosts shed eggs in urine and feces, which then contaminate water where they hatch into miracidia. These miracidia penetrate and infect snails, the intermediate hosts, where they transform into sporocysts and subsequently into cercariae. The cercariae then leave the snail to infect a new host, thus continuing the life cycle of the trematode. Therefore, the correct answer is A) Miracidia.