In the life cycle of liver fluke the sheep get infection when they ingest
A. encysted cercariae
B. miracidia
C. sporocysts
D. rediae
C. sporocysts
In the life cycle of the liver fluke, sheep get infected when they ingest C. sporocysts.
In the life cycle of a liver fluke, sheep become infected when they ingest certain stages of the parasite. To determine the correct answer, let's examine each option one by one.
A. Encysted cercariae: Cercariae are free-swimming larvae that are released from snails. However, in the case of liver flukes, they do not directly infect sheep. Instead, cercariae develop into metacercariae, which are the infectious stage for mammals. Therefore, option A is not the correct answer.
B. Miracidia: Miracidia are the first larval stage of liver flukes. After being excreted by infected sheep, they require an intermediate host, a specific type of freshwater snail. Inside the snail, miracidia develop into sporocysts. Therefore, option B is not the correct answer either.
C. Sporocysts: Sporocysts are the second larval stage of liver flukes. They develop from miracidia inside the intermediate host, the freshwater snail. Sporocysts go through further developmental stages and eventually produce small larvae called cercariae. These cercariae are released from the snail into the environment, where they can infect other hosts. Therefore, option C is also not the correct answer.
D. Rediae: Rediae are the third larval stage of liver flukes. They are produced by the sporocysts inside the snail. Rediae give rise to daughter rediae, which then produce cercariae. The cercariae are released from the snail and can infect sheep when they ingest contaminated water or vegetation. Therefore, option D is the correct answer.
So, the correct answer is D. Rediae. The infection occurs when sheep ingest the cercariae, which are the larvae released from rediae.