1. Liver Flukes Fasciola hepatica Fasciola gigantica Fascioloides magna
Dicrocoelium dendriticum
Clonorchis sinensis

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

4. 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!

5. 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

6. 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.

8. Fasciola gigantica
Equivalent of F. hepatica in Southeast Asia, Hawaii, and Africa.
Basically big species of F. hepatica.
75 mm long mm long

9. 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!

10. 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!

11. Dicrocoelium dendriticum The Lancet Fluke
Sheep, goats, deer, cattle, rabbits, and woodchucks.
Occasionally found in people.
10 mm long

12. Dicrocoelium dendriticum The Lancet Fluke
Cosmopolitan distribution but predominantly found in Eastern Europe.

13. 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

14. Clonorchis sinensis “Chinese Liver Fluke or Oriental Liver Fluke”
Korea
Thailand
Vietnam
Japan
China

15. Life Cycles!
Liver fluke of ruminants and man: Fasiola hepatica, Fasciola gigantica and Fascioloides magna!

16. Life Cycles of Ruminant Liver Flukes
First intermediate hosts are snails in the family Lymnaeidae (pond snails): these are aquatic and semi-aquatic snails.

17. Liver flukes of ruminants (aquatic life cycle).

18. Eggs of Fasciola hepatica
Eggs are X μm; golden brown, indistinct operculum, and unembryonated.

19. Miricidia develop in the egg (9-10 days) in the external environment, hatch and infect snail 1st IH

20. In the snail they develop sporocysts, 2 redia generations which release cercariae into the external aquatic environment! (five to seven weeks)

21. Cercariae encyst as metacercariae on aquatic vegetation!
Grass and water cress are typical 2nd IH

22. What happens in the DH

23. What happens in the DH
Juvenile worms penetrate the small intestine: enter the coelom and creep over the viscera until contacting the liver capsule!

24. 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.

25. 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 wk. Live for 11 years!

26. Habitat Found In
Flooded Pastures!

28. Life cycle of Dicrocoelium dendriticum The Lancet Fluke
Terrestrial life cycle!

29. Terrestrial land snails 1st IH

30. Terrestrial land snails 1st IH
Ants 2nd IH
Terrestrial land snails 1st IH

31. Terrestrial land snails 1st IH
Up to 50,000 worms in 1 DH!
Ants 2nd IH
Terrestrial land snails 1st IH

32. Life Cycle of Clonorchis sinensis “Chinese Liver Fluke”
Aquatic life cycle!

33. Snails 1st IH ingest eggs
Miracidium
Sporocyst
Rediae

34. Snails 1st IH ingest eggs
Miracidium
Sporocyst
Rediae
Cercariae
Encyst under scale or in muscle of freshwater fish 2nd IH
Metacercariae

35. 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

36. Eggs of Clinorchis sinensis
Vase shaped, X µm long, golden brown with a distinct operculum and abopercular knob.

37. Commercial Fish Ponds

38. 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!

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

42. 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.

43. Fasciola hepatica
Pipestem fibrosis

44. Fasciola hepatica

45. White areas show cirrhosis in infected liver!

46. Big Picture for Major Pathology
FIBROSIS!

47. 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 can cause seizures!

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

49. Bottle Jaw

50. 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 reinfected!