Transcript Quiz 1 - Matthew Bolek, Amphibian Parasitology

Liver Flukes
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Fasciola hepatica
Fasciola gigantica
Fascioloides magna
Dicrocoelium dendriticum
Clonorchis sinensis
Habitat: live in the duct system of the liver!
Between any three liver cells there is a
bile capillary (Bile Canaliculus)
Flukes feed on epithelial cells, blood, and mucous caused by
destruction of these cells!
Fasciola hepatica “The Sheep Liver Fluke”
• Because sheep are the
normal definitive host.
• In places where sheep
are not raised can be
found in cattle.
• Humans can become
infected!
30 mm long
Fasciola gigantica
• Equivalent of F.
hepatica in Southeast
Asia, Hawaii, and
Africa.
• Basically big species of
F. hepatica.
75 mm long
30 mm long
Fascioloides magna “Giant Deer Fluke
or Giant Liver Fluke”
• Found in deer, moose,
and elk.
• Sometimes in cattle,
bison, sheep, goats,
llamas, and pigs.
• Never found in people!
100 mm long!
Fascioloides magna “Giant Deer Fluke
or Giant Liver Fluke”
• Domestic ruminants
are aberrant hosts.
• Common parasite in
N. America especially
in the Gulf coast,
N.W., and Great
Lakes area!
Dicrocoelium dendriticum The Lancet
Fluke
• Sheep, goats, deer,
cattle, rabbits, and
woodchucks.
• Occasionally found in
people.
10 mm long
Dicrocoelium dendriticum The Lancet
Fluke
• Cosmopolitan distribution but predominantly
found in Eastern Europe.
Clonorchis sinensis “Chinese Liver Fluke
or Oriental Liver Fluke”
• Carnivorous animals
are definitive hosts.
• Dogs and cats (animals
that eat fish-2nd IH) also
occurs in people.
• Also found in pigs, rats
and camels (?)!
8-25 mm long
Clonorchis sinensis “Chinese Liver Fluke
or Oriental Liver Fluke”
• Orient
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Korea
Thailand
Vietnam
Japan
China
Life Cycles!
• Liver fluke of ruminants and man: Fasiola
hepatica, Fasciola gigantica and Fascioloides
magna!
Life Cycles of Ruminant Liver Flukes
• First intermediate
hosts are snails in the
family Lymnaeidae
(pond snails): these are
aquatic and semiaquatic snails.
Liver flukes of
ruminants
(aquatic life
cycle).
Eggs of Fasciola hepatica
Eggs are 130-150 X 63-90 μm; golden brown, indistinct
operculum, and unembryonated.
Miricidia develop in the egg (9-10 days)
in the external environment, hatch and
infect snail 1st IH
In the snail they develop sporocysts, 2 redia generations
which release cercariae into the external aquatic
environment! (five to seven weeks)
Cercariae encyst as metacercariae on
aquatic vegetation!
Grass and water cress are typical
2nd IH
What happens in the DH
What happens in the DH
• Juvenile worms penetrate the small intestine:
enter the coelom and creep over the viscera until
contacting the liver capsule!
What happens in the DH
• Juvenile worms penetrate the small intestine:
enter the coelom and creep over the viscera until
contacting the liver capsule!
• They then burrow into the liver parenchyma:
wander about for almost two months feeding and
growing.
What happens in the DH
• Juvenile worms penetrate the small intestine:
enter the coelom and creep over the viscera until
contacting the liver capsule!
• They then burrow into the liver parenchyma:
wander about for almost two months feeding and
growing.
• Finally they enter the bile ducts: worms become
sexually mature in another month and begin
producing eggs. PPP- 8-10 wk. Live for 11 years!
Fasciola hepatica “The Sheep Liver Fluke”
• Distribution is cosmopolitan, and they are
found primarily in agricultural animals.
• In US and S. America commonly found in
sheep and cattle.
Habitat Found In
Flooded Pastures!
Life cycle of Dicrocoelium dendriticum
The Lancet Fluke
Terrestrial life cycle!
Terrestrial
land snails 1st
IH
Cercariae accumulate and produce mucus
Ants 2nd IH
Terrestrial
land snails 1st
IH
Slimeball!
(500 cercariae)
“Brainworms”
Attachment to
subesophageal
ganglion
Ants 2nd IH
Terrestrial
land snails 1st
IH
Up to
50,000
worms in 1
DH!
Ants 2nd IH
Terrestrial
land snails 1st
IH
Life cycle of Dicrocoelium dendriticum
The Lancet Fluke
• Rabbits (also DHs)
– Intensity infections in sheep/goats
• Deer (also DHs)
– Disseminate between populations
• Sale/Trade of infected sheep
– Establish entirely new populations
Life Cycle of Clonorchis sinensis
“Chinese Liver Fluke”
• Aquatic life cycle!
Clonorchis sinensis
Snails 1st IH ingest eggs
Miracidium
Sporocyst
Rediae
Clonorchis sinensis
Snails 1st IH ingest eggs
Miracidium
Sporocyst
Rediae
Cercariae
Encyst under scale or in
muscle of freshwater fish
2nd IH
Metacercariae
Clonorchis sinensis
Snails 1st IH ingest eggs
Miracidium
Sporocyst
Rediae
Cercariae
Encyst under scale or in
muscle of freshwater fish
2nd IH
Metacercariae
Adult DH
Egg production 1
month
3 months total
Adults live 8 years
Eggs of Clonorchis sinensis
• Vase shaped, 26-30 X
15-17 µm long, golden
brown with a distinct
operculum and
abopercular knob.
Commercial Fish Ponds
Night soil!
What do liver flukes do to the host?
• Seldom kill host; but do interfere with
health of the host.
• More significant to us because of
agriculture.
• If animals are infected, they are sick and
don’t gain weight, won’t produce milk, etc.
• In Gulf coast states up to 23% of meat is
lost due to liver flukes!
Pathological Damage
• Mechanical Damage: Worms get numerous
and clog up bile ducts.
Pathological Damage
• Mechanical Damage: Worms get numerous
and clog up bile ducts.
– Hard to digest.
– If bile can’t get out it will kill liver cells
(necrosis of liver cells).
– Calcium deposits in bile ducts fibrosis, and
lots of scar tissue eventually causing
calcification of ducts, making them useless.
Fasciola hepatica
Pipestem fibrosis
Fasciola hepatica
White areas show cirrhosis in infected liver!
Big Picture for Major Pathology
FIBROSIS!
2ndary Pathology
• Metacercariae penetrate intestine and
migrate through body cavity (they don’t
have a map!) through diaphragm and enter
liver from outside.
• Most make it but some become lost and
become ECTOPIC INFECTIONS!
• If encapsulated in wrong place (eyes, brain,
skin, lungs) can cause seizures!
Symptoms
• Adult liver flukes feed on bile duct epithelium
and suck blood, so symptoms are anemia,
hypoalbuminemia, hypoproteinemia.
Bottle Jaw
Symptoms
• Diarrhea, edema, and enlarged liver.
• Lower abdominal pain and discomfort (can
last for up to 10 yrs after treatment and no
probability of getting re-infected!