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 is the diagnostic stage of trematodes?
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.
What is the life cycle of flukes?
Life Cycle: The adult flukes deposit fully developed eggs that are passed in the feces . After ingestion by a suitable snail (first intermediate host) , the eggs release miracidia , which undergo in the snail several developmental stages (sporocysts , rediae , cercariae ).
Which life cycle stage of the trematode life cycle is infective to the vertebrate host?
Adult metacercariae or mesocercariae, depending on the individual trematode’s life cycle, will then infect the vertebrate host or be rejected and excreted through the rejected host’s faeces or urine.
How do the life cycle of trematodes and Cestodes differ?
Cestodes are tape-like and segmented in shape, have a head with suckers and possibly hooks, and lack a digestive tract. Trematodes are leaf-like and unsegmented, lack hooks entirely, and have an incomplete digestive tract. Generally, cestodes require two hosts and trematodes need three to complete their life cycles.
How does a trematode typically look like?
Trematodes are flattened oval or worm-like animals, usually no more than a few centimetres in length, although species as small as 1 millimetre (0.039 in) are known. Their most distinctive external feature is the presence of two suckers, one close to the mouth, and the other on the underside of the animal.
How long can flukes live without a host?
The lifecycle without a host can be completed within a few days. An adult can live up to 6 days without a host. After an egg hatches the oncomiridium must find a host within 36 hours or it will die. A fluke cannot attack an invertebrate or coral.
What are examples of trematode?
What are some of the important trematode parasites of human?
The most important trematodes are Schistosoma species (blood flukes), Clonorchis sinensis (liver fluke), and Paragonimus westermani (lung fluke). Schistosomes have by far the greatest impact in terms of the number of people infected, morbidity, and mortality.
What is the life cycle of a trematode?
The life cycle of a typical trematode begins with an egg. Some trematode eggs hatch directly in the environment (water), while others are eaten and hatched within a host, typically a mollusc.
Do all trematodes have a redia stage?
Not all trematode species have a redia stage; some may just have a sporocyst stage depending on the life cycle. The rediae are dominant over sporocysts because they have mouths and are able to either eat their competitors’ food or their competitors. The larval form of the parasite develops within the germinal cells of the sporocyst or redia.
How do trematodes reproduce?
As an adult, it is capable of sexual reproduction. Not all trematodes follow the typical sequence of eggs, miracidia, sporocysts, rediae, cercariae, and adults. In some species, the redial stage is omitted, and sporocysts produce cercariae. In other species, the cercaria develops into an adult within the same host.
What is the function of the tegument in a trematode?
Trematodes are covered by a tegument, that protects the organism from the environment by providing secretory and absorptive functions. The life cycle of a typical trematode begins with an egg.