PHYLUM PLATYHELMINTHES

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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 1. Echinostoma
revolutum -- DH any bird or mammal in gut
uterus w/ eggs
vitellaria
ovary
shell gland?
testes
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 1. Echinostoma
revolutum a. Life cycle -- eggs out with
feces -- miracidium into Physa
or Helisoma (extra credit)
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 1. Echinostoma
revolutum a. Life cycle -- redia
(carnivorous) -- cercaria --
metacercaria in molluscs, fish, tadpoles --
metacercaria eaten by DH
metacercaria
cercaria
redia
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 2. Fasciola
hepatica sheep liver fluke
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 2. Fasciola
hepatica sheep liver fluke
genital pore
uterus
ovary
testes
vitellaria
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 2. Fasciola
hepatica sheep liver fluke a. Life cycle
-- adults in liver and bile duct of sheep
-- eggs out with feces -- miracicium
infects Stagnicola (extra credit)
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 2. Fasciola
hepatica sheep cow liver fluke a. Life
cycle -- sporocyst 2 generations of
redia -- cercaria released --
metacercaria encyst on vegetation eaten by DH
redia
cercaria
metacercaria
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 2. Fasciola
hepatica sheep cow liver fluke a. Life
cycle -- metacercaria excysts penetrates
gut wall -- creeps over viscera to liver
-- burrow through liver for ca. 2 months into
bile duct ? adult -- adult fluke can live
up to 11 yrs.
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 2. Fasciola
hepatica sheep cow liver fluke b.
Pathology causes liver rot in livestock
-- migrating fluke causes extensive damage
-- adult flukes cause fibrous cysts abscess
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Fasciola hepatica liver rot
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 2. Fasciola
hepatica sheep cow liver fluke a. Life
cycle b. Pathology c. Control --
enormous egg output 1 fluke ?
20,000 eggs/day host can have 100
adult flukes in liver 1 infected
host ? 200 million eggs/day -- possible
biological control agent Nosema sp.
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea (digenetic flukes) D.
Order Echinostomatiformes 3. Fasciolopsis
buski DH pigs humans
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Echinostomatiformes 3. Fasciolopsis
buski -- egg in feces -- miracidium infects
Segmentina (extra credit) -- cercaria released --
metacercaria encysts on vegetation -- ingested by
DH can cause diarrhea, toxic reactions,
ulceration, blockage
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Echinostomatiformes 3. Paramphistomum
cervi -- DH domestic ruminants in rumen --
life cycle similar to F. hepatica uses same
snail, Stagnicola (extra credit)
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Paramphistomum cervi
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes -- cercaria with oral stylet
(xiphidiocercaria) -- many use an arthropod as
2nd IH 1. Dicrocoelium dendriticum (the lancet
fluke) DH sheep, pigs, goats, cattle in
bile duct
Dicrocoelium
Fasciola
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Dicrocoelium dendriticum life cycle
(terrestrial)
6. Ant eaten by DH
1. Adult in liver of DH eggs out with feces
5. Metacercaria encyst in abdomen 1-2 in brain
activates ancient sleeping behavior

• Eggs eaten by
• Cionella miracidium
• hatches

• sporocysts
• cercaria move to
• lung

4. Cercaria ejected in slime balls eaten by
ant, Formica
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 1. Dicrocoelium
dendriticum DH sheep, pigs, goats,
cattle in bile duct
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 2. Prosthogonimus
macrorchis -- DH chicken in oviduct --
eggs into cloaca out with feces
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-- eggs eaten by Amnicola (extra credit) --
cercaria released sucked into anal lung of
dragonfly nymph ? metacercaria -- eaten by
chicken ? cloaca ? up into oviduct
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke -- DH carnivores zoonosis
in humans
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke a. Life cycle -- adult
flukes encysted in lungs
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke a. Life cycle -- eggs
up trachea swallowed out with feces --
miracidium penetrates thiarid snail
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke a. Life cycle --
microcercous cercaria released -- crawls
to 2nd IH freshwater
crustacean -- encyst as metacercaria
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke a. Life cycle --
infected crustacean eaten by human (drunken
crab) -- metacercaria excysts penetrates
gut, diaphragm into lungs
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke b. Pathology 1) eggs
in lungs ? pseudotubercles
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke b. Pathology 2)
encapsulation of adults
Dog lung
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke b. Pathology 3)
ectopic adults (and eggs)
Paragonimus in human brain
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke b. Pathology 3)
ectopic adults
Paragonimus in human brain
soap bubble lesion
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Cerebral paragonimiasis
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 3. Paragonimus westermani
human lung fluke b. Pathology 3)
ectopic adults
Paragonimus eggs in human brain
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 4. Nanophyetes
salmincola -- DH raccoons, skunks in small
intestines (many piscivorous mammals (humans)
and birds) -- eggs in feces -- snail host
Oxytrema (extra credit) -- metacercaria in
fish -- eaten by DH
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea D. Order
Plagiorchiformes 4. Nanophyetes
salmincola In canids transmits
Neorickettsia helminthoeca causes salmon
poisoning -- fever, facial swelling,
vomiting, diarrhea -- host usually dies
within 10-14 days -- if canid survives ?
permanent immunity
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea E. Order
Opisthorchiformes 1. Clonorchis sinensis
human liver fluke
gut
uterus w/ eggs
vitellaria
ovary
seminal receptacle
testes
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea E. Order
Opisthorchiformes 1. Clonorchis sinensis
human liver fluke a. Life cycle --
adults in bile ducts of human liver --
eggs out with feces
operculum
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea E. Order
Opisthorchiformes 1. Clonorchis sinensis
human liver fluke a. Life cycle -- egg
eaten by snail, Parafossarulus --
sporocyst ? redia ? cercaria
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea E. Order
Opisthorchiformes 1. Clonorchis sinensis
human liver fluke a. Life cycle --
cercaria penetrate skin of fish --
metacercaria form in fish muscle
-- eaten by human host
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea E. Order
Opisthorchiformes 1. Clonorchis sinensis
human liver fluke b. Pathology 1)
level of infection -- moderate
infection 100-1000 flukes -- each
produces 4000 eggs/day -- may live
up to 8 years


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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea E. Order
Opisthorchiformes 1. Clonorchis sinensis
human liver fluke b. Pathology 2)
blockage of bile duct -- enlargement
of liver and spleen -- bile duct
cancer
Enlarged hepatic ducts arrows indicate
Clonorchis
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Healthy rat liver
Rat liver with Clonorchis infection


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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea E. Order
Opisthorchiformes 1. Heterophyes
heterophyes DH human in small intestines
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PHYLUM PLATYHELMINTHES II. Class Trematoda
Subclass Digenea E. Order
Opisthorchiformes 1. Heterophyes
heterophyes -- eggs in feces -- infect snail,
Cerithidia -- metacercaria form in fish
muscle -- eaten by human can perforate
gut -- eggs accumulate in tissues ?
heart ? brain and spinal cord