Liver FlukesLiver Flukes

• Fasciola hepaticaFasciola hepatica

• Fasciola giganticaFasciola gigantica

• Fascioloides magnaFascioloides magna

• Dicrocoelium dendriticumDicrocoelium dendriticum

• Clonorchis sinensisClonorchis sinensis

Habitat: live in the duct system of the liver!Habitat: live in the duct system of the liver!

Between any three liver cells there is a Between any three liver cells there is a bile capillary (Bile Canaliculus)bile capillary (Bile Canaliculus)

Flukes feed on epithelial cells, blood, and mucous caused by destruction of these cells!

Fasciola hepatica Fasciola hepatica “The Sheep Liver Fluke”“The Sheep Liver Fluke”

• Because sheep are the Because sheep are the normal definitive host.normal definitive host.

• In places where sheep In places where sheep are not raised can be are not raised can be found in cattle.found in cattle.

• Humans can become Humans can become infected!infected!

30 mm long

Fasciola hepatica Fasciola hepatica “The Sheep Liver Fluke”“The Sheep Liver Fluke”

• Distribution is cosmopolitan, and they are Distribution is cosmopolitan, and they are found primarily in agricultural animals.found primarily in agricultural animals.

• In US and S. America commonly found in In US and S. America commonly found in sheep and cattle.sheep and cattle.

Fasciola gigantica Fasciola gigantica

• Equivalent of Equivalent of F. F. hepaticahepatica in Southeast in Southeast Asia, Hawaii, and Asia, Hawaii, and Africa.Africa.

• Basically big species of Basically big species of F. hepaticaF. hepatica..

75 mm long 30 mm long

Fascioloides magnaFascioloides magna “Giant Deer Fluke “Giant Deer Fluke or Giant Liver Fluke”or Giant Liver Fluke”

• Found in deer, moose, Found in deer, moose, and elk.and elk.

• Sometimes in cattle, Sometimes in cattle, bison, sheep, goats, bison, sheep, goats, llamas, and pigs.llamas, and pigs.

• Never found in people! Never found in people!

100 mm long!

Fascioloides magnaFascioloides magna “Giant Deer Fluke “Giant Deer Fluke or Giant Liver Fluke”or Giant Liver Fluke”

• Domestic ruminants Domestic ruminants are aberrant hosts.are aberrant hosts.

• Common parasite in Common parasite in N. America especially N. America especially in the Gulf coast, in the Gulf coast, N.W., and Great Lakes N.W., and Great Lakes area! area!

Dicrocoelium dendriticum Dicrocoelium dendriticum The Lancet The Lancet FlukeFluke

• Sheep, goats, deer, Sheep, goats, deer, cattle, rabbits, and cattle, rabbits, and woodchucks.woodchucks.

• Occasionally found in Occasionally found in people. people.

10 mm long

Dicrocoelium dendriticum Dicrocoelium dendriticum The Lancet The Lancet FlukeFluke

• Cosmopolitan distribution but predominantly Cosmopolitan distribution but predominantly found in Eastern Europe. found in Eastern Europe.

Clonorchis sinensis “Clonorchis sinensis “Chinese Liver Fluke Chinese Liver Fluke or Oriental Liver Fluke”or Oriental Liver Fluke”

• Carnivorous animals Carnivorous animals are definitive hosts.are definitive hosts.

• Dogs and cats (animals Dogs and cats (animals that eat fish-2that eat fish-2ndnd IH) also IH) also occurs in people.occurs in people.

• Also found in pigs, rats Also found in pigs, rats and camels (?)!and camels (?)!

8-25 mm long

Clonorchis sinensis “Clonorchis sinensis “Chinese Liver Fluke Chinese Liver Fluke or Oriental Liver Fluke”or Oriental Liver Fluke”

• OrientOrient– KoreaKorea– ThailandThailand– VietnamVietnam– JapanJapan– ChinaChina

Life Cycles! Life Cycles!

• Liver fluke of ruminants and man: Liver fluke of ruminants and man: Fasiola Fasiola hepatica, Fasciola gigantica hepatica, Fasciola gigantica and and Fascioloides magnaFascioloides magna!!

Life Cycles of Ruminant Liver FlukesLife Cycles of Ruminant Liver Flukes

• First intermediate First intermediate hosts are snails in the hosts are snails in the family Lymnaeidae family Lymnaeidae (pond snails): these are (pond snails): these are aquatic and semi-aquatic and semi-aquatic snails.aquatic snails.

Liver flukes of ruminants (aquatic life cycle).

Eggs of Eggs of Fasciola hepaticaFasciola hepatica

Eggs are 130-150 X 63-90 μm; golden brown, indistinct operculum, and unembryonated.

Miricidia develop in the egg (9-10 days) Miricidia develop in the egg (9-10 days) in the external environment, hatch and in the external environment, hatch and

infect snail 1infect snail 1stst IH 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 Cercariae encyst as metacercariae on aquatic vegetation!aquatic vegetation!

Grass and water cress are typical 2nd IH

What happens in the DHWhat happens in the DH

What happens in the DHWhat happens in the DH• Juvenile worms penetrate the small intestine: Juvenile worms penetrate the small intestine:

enter the coelom and creep over the viscera until enter the coelom and creep over the viscera until contacting the liver capsule!contacting the liver capsule!

What happens in the DHWhat happens in the DH• Juvenile worms penetrate the small intestine: Juvenile worms penetrate the small intestine:

enter the coelom and creep over the viscera until enter the coelom and creep over the viscera until contacting the liver capsule!contacting the liver capsule!

• They then burrow into the liver parenchyma: They then burrow into the liver parenchyma: wander about for almost two months feeding and wander about for almost two months feeding and growing.growing.

What happens in the DHWhat happens in the DH• Juvenile worms penetrate the small intestine: enter Juvenile worms penetrate the small intestine: enter

the coelom and creep over the viscera until the coelom and creep over the viscera until contacting the liver capsule!contacting the liver capsule!

• They then burrow into the liver parenchyma: wander They then burrow into the liver parenchyma: wander about for almost two months feeding and growing.about for almost two months feeding and growing.

• Finally they enter the bile ducts: worms become Finally they enter the bile ducts: worms become sexually mature in another month and begin sexually mature in another month and begin producing eggs. PPP- 8-10 wk. Live for 11 years! producing eggs. PPP- 8-10 wk. Live for 11 years!

Habitat Found InHabitat Found In

Flooded Pastures!

Life cycle of Life cycle of Dicrocoelium dendriticum Dicrocoelium dendriticum The Lancet FlukeThe Lancet Fluke

Terrestrial life cycle!

Terrestrial land snails 1st

IH

Terrestrial land snails 1st

IH

Ants 2nd IH

Terrestrial land snails 1st

IH

Ants 2nd IH

Up to 50,000

worms in 1 DH!

Life Cycle of Life Cycle of Clonorchis sinensis Clonorchis sinensis ““Chinese Liver Fluke”Chinese Liver Fluke”

• Aquatic life cycle!Aquatic life cycle!

Snails 1st IH ingest eggs

Miracidium

Sporocyst

Rediae

Cercariae

Encyst under scale or in muscle of freshwater fish 2nd IH

Snails 1st IH ingest eggs

Miracidium

Sporocyst

Rediae

Metacercariae

Egg production 1 month

Cercariae

Encyst under scale or in muscle of freshwater fish 2nd IH

Snails 1st IH ingest eggs

Miracidium

Sporocyst

Rediae

Metacercariae

Adult DH

3 months total

Adults live 8 years

Eggs of Eggs of Clinorchis sinensisClinorchis sinensis

• Vase shaped, 26-30 X Vase shaped, 26-30 X 15-17 15-17 µm long, golden µm long, golden brown with a distinct brown with a distinct operculum and operculum and abopercular knob.abopercular knob.

Commercial Fish PondsCommercial Fish Ponds

What do liver flukes do to the host?What do liver flukes do to the host?

• Seldom kill host; but do interfere with Seldom kill host; but do interfere with health of the host.health of the host.

• More significant to us because of More significant to us because of agriculture.agriculture.

• If animals are infected, they are sick and If animals are infected, they are sick and don’t gain weight, won’t produce milk, etc.don’t gain weight, won’t produce milk, etc.

• In Gulf coast states up to 23% of meat is In Gulf coast states up to 23% of meat is lost due to liver flukes!lost due to liver flukes!

Pathological DamagePathological Damage

• Mechanical Damage: Worms get numerous Mechanical Damage: Worms get numerous and clog up bile ducts.and clog up bile ducts.

Pathological DamagePathological Damage

• Mechanical Damage: Worms get numerous Mechanical Damage: Worms get numerous and clog up bile ducts.and clog up bile ducts.– Hard to digest.Hard to digest.– If bile can’t get out it will kill liver cells If bile can’t get out it will kill liver cells

(necrosis of liver cells).(necrosis of liver cells).– Calcium deposits in bile ductsCalcium deposits in bile ducts fibrosis, and fibrosis, and

lots of scar tissue eventually causing lots of scar tissue eventually causing calcification of ducts, making them useless.calcification of ducts, making them useless.

Fasciola hepaticaFasciola hepatica

Pipestem fibrosis

Fasciola hepaticaFasciola hepatica

White areas show cirrhosis in infected liver!

Big Picture for Major PathologyBig Picture for Major Pathology

FIBROSIS!FIBROSIS!

22ndaryndary Pathology Pathology

• Metacercariae penetrate intestine and Metacercariae penetrate intestine and migrate through body cavity (they don’t have migrate through body cavity (they don’t have a map!) through diaphragm and enter liver a map!) through diaphragm and enter liver from outside. from outside.

• Most make it but some become lost and Most make it but some become lost and become ECTOPIC INFECTIONS! become ECTOPIC INFECTIONS!

• If encapsulated in wrong place can cause If encapsulated in wrong place can cause seizures!seizures!

SymptomsSymptoms

• Adult liver flukes feed on bile duct epithelium Adult liver flukes feed on bile duct epithelium and suck blood, so symptoms are anemia, and suck blood, so symptoms are anemia, hypoalbuminemia, hypoproteinemia.hypoalbuminemia, hypoproteinemia.

Bottle JawBottle Jaw

SymptomsSymptoms

• Diarrhea, edema, and enlarged liver.Diarrhea, edema, and enlarged liver.

• Lower abdominal pain and discomfort (can Lower abdominal pain and discomfort (can last for up to 10 yrs after treatment and no last for up to 10 yrs after treatment and no probability of getting reinfected! probability of getting reinfected!