Table of Contents
- 1 How are trematodes diagnosed?
- 2 Do trematodes lay eggs?
- 3 What is the definitive host of trematodes?
- 4 What is the life cycle of trematode?
- 5 What stage of trematodes swims in the water?
- 6 What is the life cycle of trematodes?
- 7 What is the life cycle of liver fluke?
- 8 Where do the eggs of a trematode come from?
- 9 How is the diagnosis of a trematode infection made?
- 10 Where does fertilization take place in a Trematoda?
How are trematodes diagnosed?
Detection of antigen in the stool (coproantigen) is a nonmicroscopic method of diagnosis for intestinal trematodes. An enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody to an 89-kd antigen of O viverrini has been used to detect coproantigen in the stool of individuals with O pisthorchis infection.
Do trematodes lay eggs?
The reproductive system consists of male and female reproductive organs and is complete in each fluke. The flukes are oviparous. They lay operculated eggs. An exception is schistosome eggs, which are not operculated.
Why do trematodes produce so many eggs?
Because of the small chance of transmission of parasite stages from host to host, internal parasites put much energy into reproduction, producing many, many eggs and/or larvae because so few ever reach the next host in the life cycle.
What is the definitive host of trematodes?
A species that exemplifies the remarkable life history of the trematodes is the bird fluke, Leucochloridium paradoxum. The definitive hosts, in which the parasite reproduces, are various woodland birds, while the hosts in which the parasite multiplies (intermediate host) are various species of snail.
What is the life cycle of trematode?
There are three distinct larval stages involved in all digenetic trematode life cycles: the miracidium, sporocyst, and cercaria. Some taxa also produce rediae and/or encysted metacercariae. All of these life stages except for the miracidium can be found in first intermediate hosts.
What stage of Schistosoma infects humans?
The stages in the snail include two generations of sporocysts and the production of cercariae. Upon release from the snail, the infective cercariae swim and penetrate the skin of the human host, where maturation of the worms continues. Oncomelania spp. are the intermediate hosts for S.
What stage of trematodes swims in the water?
The hatchling is called a miracidium, a free-swimming, ciliated larva. Miracidia will then grow and develop within the intermediate host into a sac-like structure known as a sporocyst or into rediae, either of which may give rise to free-swimming, motile cercariae larvae.
What is the life cycle of trematodes?
The trematode life cycle is completed when eggs shed by adult worms are excreted in host feces and hatch to release ciliated miracidia, which then infect a suitable intermediate host.
Do trematodes have a through gut?
Despite the presence of a gut, trematodes seem able to absorb glucose and certain other materials through the metabolically active tegument covering the body surface. Tapeworms, which have no gut, absorb all nutrients through the tegument.
What is the life cycle of liver fluke?
Following ingestion, the young flukes migrate to the liver, through which they tunnel, causing considerable tissue damage. The infection is patent about 10-12 weeks after the metacercariae are ingested. The whole cycle takes 18-20 weeks.
Where do the eggs of a trematode come from?
The eggs of all trematodes (except schistosomes) are operculated. Some eggs are eaten by the intermediate host (snail) or they are hatched in their habitat (water). Miracidia hatch from eggs either in the environment or in the intermediate host.
How is the life cycle of a trematode completed?
The trematode life cycle is completed when eggs shed by adult worms are excreted in host feces and hatch to release ciliated miracidia, which then infect a suitable intermediate host.
How is the diagnosis of a trematode infection made?
Diagnosis of trematode infection is commonly accomplished by identification of eggs in feces or urine. The eggs of most species are structurally distinct and the diagnosis can be made by standard light microscopy. With the exception of fascioliasis, the drug of choice for trematode infections is praziquantel.
Where does fertilization take place in a Trematoda?
In most trematodes, sperm cells travel through the uterus to reach the ootype, where fertilization occurs. The ovary is sometimes also associated with a storage sac for sperm, and a copulatory duct termed Laurer’s canal.