Question

1. What are the differences in life cycle among C. sinensis, P. westermani and

S. japonicum ? (Site of inhabitation, infective stage, infective route, larval stage, intermediate host, definitive host, reservior host, etc)

Answer 1

Answer

According to the given question-

There are approximately 90 percent of animals are invertebrates those doesn't posses vertebral column. They are belongs to several phylum some are primitive and some have well developed circulatory system, nervous system, digestive system, excretory system as well as well developed body organisation. They are responsible for causing several types of disease in humans as well as in other animals. Some of the above given in the question are belongs to phylum platyhelminthes with following characteristics and life cycle.

	Clonorchis sinensis	Paragonimus westermani	Schistosoma japonicum
Site of inhabitation	In humans Common bile duct and gall bladder cause liver cirrohsis, as well as hepatic carcinoma. Called liver Fluke.	Lungs, causing paragonimiasis in gut, and diaphragm. Also called lung flukes	called blood Fluke. They are lived in blood, also migrated to spleen , brain, liver.
Infective stage	eggs are deposited in water which was first eaten by snail where the enzyme of digestive system of snail dissolve the outer layer and the larval stage miracidium hatched and developed through different larval stages and comes out from the snail body as mature cercariae larva and for the search of fishes.	Unembryoonated egg from the sputum of human developed into Miracidium larva which penetrate into snail and developed into rediae larva which developed into cercariae larva and comes from the snail to water and attached with the muscles of crab and developed into metacercaria larva. When the infected crab was eaten by mammals including humans this enter into human and penetrate in their gut, diaphragm and lungs and developed into mature adult.	Eggs of the parasites are released into feaces which in presence of water developed into miracidium larva which infect snail and developed into cercaria larva which leaves the body of snail and comes in water and it comes in contact with the skin of humans it penetrate the skin and looses its tail and developed into schistosomule which migrated through the circulation and reached at the ends of mesenteric veins where the parasite lye eggs.
Infective route	from snail to fishes to mammals. Eggs of this platyhelminthes species was eaten by snail which hatched into their digestive system and enter into their hemoceal and digestive gland. After different larval stage it developed into cercariae larval stage which leaves the body of snail and enter to the freshwater fishes through their scales. In the last when these fishes are eaten by mammals such as humans it enters into their digestive gland such as gall bladder and common bile duct.	From snail to crayfish to humans. In humans due to eating raw and not properly cooked crab form mouth to gut, diaphragm to lungs.	From snails to mammals. In mammals through their skin when comes in contact with the water where the larval stage cercariae of thisp parasites resides and attached with the skin and loses there tails and developed into schistosomule which through circulatory system reach at the end of mesenteric veins and produces the eggs. The eggs also moved to liver, brain and other part of the organs.
Larval stage	miracidium developed into rediae which developed into mature cercaria larva.	Miracidium developed into rediae larve which developed into cercariae and last in metacercariae larval	Miracidium developed into rediae which developed into cercariae and in the last into  schistosomule.
Intermediate host	freshwater fishes	crabs or crayfish	primary host is snail no intermediate host
Definite host	fish eating mammals such as cats, dogs, pigs, rats including humans.	Mammals including humans	wild mammals, some insectivore, rodents, some carnivorous and humans.
Reservoir host	dogs and pigs	dogs and pigs	no reservoir host.