Trematodes Flashcards
Give an example of Trematodes
Flukes and flatworm
Small dorso-ventrally
flattened worms with
simple anatomy and
without segmentation
Tematodes
Do they have coelom?
NOPE
Describe trematodes
Digenea posses two suckers (oral and ventral acetabulum) which they use to attach within the host. Oral sucker contains the mouth • Muscular pharynx permits the worm to pump food into the blind-ending gut • Most trematodes are hermaphrodites (they are male and female, and cross- as well as selffertilization occurs)
Describe the gut of trematodes
The gut of trematodes is
blind-ending but can be
quite extensive and highly
branched
The gut is not the only organ
these worms use for food
uptake. What else?
The tegument
A protonephridium consists of what?
flame cell and tubule cell
Trematodes are massively fertile but their lovelife is complex. T or F
True
Are the adults hermaphrodite?
Yes
Describe the reproductive system of trematodes
The reproductive system
takes up a large portion of
the body of the animal
What do you call the urinary system of trematodes?
Protonephridia
Trematodes form _________ eggs
ectolecithal
- oocytes meet with the yolk cells in the ootype which is surrounded by Mehlis gland.
Reproduction cycle: steps
Trematodes form complex ectolecithal eggs
Worm eggs travel through the uterus to the genital pore.
Egg shell is hardened by quinone tanning
Tyrosine is modified into a highly reactive quinone.
Cross liks free aminio groups
Reproduction cycles
Asexual and sexual
What does the egg contain?
The embryo instead of an oocyte
T or F: The eggs have to leave the body of the final host to continue development.
T
is highly motile
due to the cilia on its surface
Miracidium
have simple eyes (they avoid light) and several chemical and mechanical receptors which they use to find the intermediate snail host
Miracidium
After penetration the
miracidium undergoes
metamorphosis into the __________
sporocyst
This stage has most organ
systems reduced to the bare
minimum and acts as a
germinal sac
Sporocyst
takes up nutrients only over its tegument and the germinal mass expands and develops into daughter sporocysts, redia or cercaria
sporocyst
are the stages
that leave the intermediate
host and infect the final
host
Cercaria
Sporocyst can produce
cercaria or a next
amplification
generation, _______
redia
have features of the adult fluke like oral and ventral sucker, a gut and “birth pore” to release cercaria
redia
are mobile in the snail and can prey on sporocysts and redia of the same or other species (competition)
redia
The lancet fluke
Dicrocoelium dendriticum
manipulates the behavior of the ant. In the evening when the temperature drops they experience spasms of their mandibles
The brain worm
is a
tiny digenic trematode
living in the gut of small
song birds
Leucochloridium sp.
Human fluke is caused by
Clonorchis sinensis and opistorchis felinus
Transmission
Metacercaria are found in many fish especially various carp related species • Raw or undercooked fish dishes are a source of human infection • Fertilization of ponds with untreated night soil boost infection in fish • Cats, dogs and other carnivores can be additional hosts and reservoirs
Describe heavy infection of LIVER flukes
residing in the biliary ducts can chronically irritate the epithelium resulting in hyperplasia of the epithelium and fibrosis around the ducts (pipe stem fibrosis)
Diagnosis
Diagnosis occurs by
microscopic
demonstrations of fluke
eggs in the feces
is best known but a number
of other species infect
humans around the world. Can get from eating crabs
Paragonimus westermanii
Chronic high worm burden can
result in
chronic bronchitis and dyspnea and increasing fibrosis -- symptoms can be very similar to pulmonary tuberculosis
Important parasite of
livestock, occasionally
infects humans
Fasciola & Fasciolopsis
