Question

Name the two intermediate hosts on which the human liver fluke depends to complete its life cycle and induce parasitization in the primary host.

Answer 1

Hint: The liver fluke disease is caused to the human after consumption of the meat product of the intermediate host of the fluke then releasing the fluke via feces and taken up by the other host.

Complete answer:
Liver fluke is a very fatal disease and the agent which causes this disease is Fasciola hepatica. This fluke gets inside our body when we consume meat products of the sheep because sheep is an intermediate host for this organism and among the all three hosts which fluke requires to complete the life cycle, it is most lethal in the sheep. As we consume meat, this fluke reaches the liver through the digestive tract. After reaching the liver it creates a tunnel by damaging the tissues of the liver, the duodenum, and also penetrates the intestinal walls. From there it reaches the biliary ducts and after 10-18 days after causing all the damage it lays eggs and those eggs leave the body through fecal matter.
This fecal matter gets mixed with the water bodies and the eggs of the fluke remain free in the water body until it finds its second intermediate host which is the mud snail. The further development of the fluke eggs takes place inside the snail and when it reaches the stage of free-swimming cercariae they leave the snail’s body and get mixed with the vegetation along with the water body. When the sheep consume this vegetation, the fluke gets transferred and the cycle gets completed where the fluke further develops and causes problems in the sheep. The main hosts of these flukes are sheep and humans and we can stop the life cycle of this fluke by stopping consuming the sheep. The adult flukes are found at hepatic bile ducts.

Additional Information: There are different stages of life cycles which the flukes have to complete but they are condition dependent and to fulfill those conditions the fluke travels from host to host. The stages of the fluke are miracidia, sporocysts, rediae, cercariae, and metacercaria.

Note:
Not only these flukes affect the sheep but they target all the cattle which have a ruminating type of mechanism but amongst all the cattle we only consume sheep and no other cattle is consumed.