unit 5. Liver Flukes.pptbbhbbhhhhhhhhhhhhj

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1. Cercarial dermatitis
 Cutaneous lesions (itching, erythema,
urticaria, papules) in humans, caused by
skin penetration of schistosomatid
cercariae parasitizing birds
e.g., Bilharziella, Trichobilharzia
known as “swimmer’s itch”

2. Ce. De. conti
The cercariae of schistosomes from
humans can cause similar, although
usually milder, symptoms
The infection occurs worldwide in
freshwater

The symptoms generally decrease after a
few days

3. Liver Flukes
General Features
Adults are large and live in the live or
biliary duct
 Eggs are large and contain undeveloped
ovum when passed in the faeces 
They are hermaphrodite

4. Liv. Conti.
Include
Fasciola hepatica
Fasciola gigantica
Clonorchis(opisthorchis) sinensis
Opisthorchis viverrini
Opisthorchis felineus

5. Fasciola hepatica
Common name : sheep liver fluke
Geographical Distribution
Cosmopolitan; prevalent in most sheep
and cattle raising countries

6. Fa. he. Conti.
In Ethiopia
does not play an important role in human
health in Ethiopia
 only as few reported cases of the disease;
as result of finding eggs in the stools of
people who had consumed infected liver of
sheep or cattle
Causes serious economic loss throughout
the highlands in Ethiopia by infecting cattle
and sheep

7. Fa. he. Conti.
Habitat
Adult: In the bile duct of sheep, goat ,
cattle & man
Egg: In faeces
All larva stages: Fresh water snail
Metacercaria: on water vegetations

8. Fa. he. Conti.
Morphology
Adult
Size: 30 mm by 12 mm
Shape: fleshy , flat, leaf-like
Colour: grey brown
Cone shaped prominent two “
shoulders”

9. Fasciola hepatica adult stage

10. Fa. he. Conti.
Egg
Size: 130-150m by 60-90m
Shape: oval with rounded poles
Shell: smooth with a double line &
marked operculum at one pole
Colour: bile-stained or yellow to dark brown

11. Fa. he. Conti.
Eggs

12. Fa. he. Conti.
Life cycle
Immature eggs are discharged in the stool

Eggs become embryonated in water , eggs
release miracidia
miracidia invade snail intermediate
host : genus Lymnae 
miracidia sporocysts rediae
cercariae  

13. Fa. he. Conti.
cercariae are released from the snail and
encyst as metacercariae on aquatic
vegetation
Mammals acquire the infection by eating
vegetation containing metacercariae
After ingestion, the metacercariae excyst
in the duodenum

14. Fa. he. Conti.
migrate through the intestinal wall in to
peritoneal cavity
Then, they penetrate liver capsule and
reach to biliary ducts, where they
develop into adults
In humans, maturation from
metacercariae into adult flukes takes about
3 to 4 months

15. Life cycle of F.hepatica and F.gigantica

16. Fa. he. Conti.
Clinical feature and pathology
Light infections are usually asymptomatic
In heavy infection
Local irritation during migration of the
young worms to the liver
Fever, Sweating, abdominal pain
In chronic infection: obstructive jaundice
Persistent diarrhea, anemia

17. Fa. he. Conti.
Laboratory Diagnosis
 
1. Finding Eggs in the faces in chronic
infection
Several specimen may also needed to
detect the egg
Concentration techniques ( fomol ether );
because the eggs usually few
 Eggs can also be found in duodenal
aspirates & in bile
2

18. Fa. he. Conti.
If eggs are found in human faces it must
be confirmed that they are present due to
a Fasciola infection & not
False Fascioliasis - due to ingestion of
animal liver containing Fasciola egg &
detected in faeces
Confirmation - keep the patient on liver free
diet for three days. If egg is found in repeated
examination the infection is true

19. Fa. he. Conti.
2. Serological diagnosis
by testing serum for antibodies
 valuable in the early stages of infection
when the immature flukes are migrating
through the liver and causing serious
symptoms but not yet producing eggs
Treatment
Bithinol or Triclabendazole

20. Fa. he. Conti.
Prevention and Control
1.Avoid eating uncooked water plants
2.Treating infected animals & fencing
grazing land known to be infected with
metacercariae
3. Identifying & destroying snail hosts &
snail habitat

21. Fa. he. Conti.
4.Sanitary disposal of faeces
5.Treating infected individuals & giving
health education

22. Fasciola giagantica
Common name: Large or Giant liver
fluke
Geographical Distribution
Widely distributed in tropical Africa
including Ethiopia, and Far East, south
and south East Asia

23. Fa. gi. conti.
Habitat
Adult: In the bile duct of sheep, goat ,
cattle
& man

Egg: In faeces
All larva stages: Fresh water snail:
Lymanae
Metacercaria: on water vegetations

24. Fa. gi. conti.
Morphology
 Similar to F.hepatica
Adult:-Size 25-75 mm by 12 mm,
larger
Egg: 160-190 m by 70-90m,
operculated
& non-embryonated, larger

25. Fa. gi. conti.
Life cycle
 similar to the life cycle of F.hepatica
except the species of snail hosts infected
by F.gigantica are aquatic not
amphibious
Clinical feature and Pathology
 Similar to F.hepatica but less adapted to
humans

26. Fa. gi. conti.
Laboratory Diagnosis
1.Eggs in the faeces
2.Eggs in aspirates of the duodenal fluid
Treatment , Prevention and Control
similar to F.hepatica

27. Clonorchis(opisthorchis)
sinensis
Common name: Chinese Liver fluke
Geographical Distribution
Far east- China, Japan, Korea, Taiwan
 

28. Cl. si. Conti.
Habitat
Adult: bile duct of man and fish eating
animals including cat , dog, pig
Eggs: In the faeces
Metacercariae: under the scale of fresh
water fish

29. Cl. si. Conti.
Morphology:
Adult- Size: 10-25 mm by 3-5 mm;Boat
shaped

30. Cl. si. Conti.
Egg: Size: 25-30m;shape like electric bulb
Colour: shell; yellowish brown; contents pale
yellow
Operculum: At the narrow end of the egg,

31. Cl. si. Conti.
Life cycle
Embryonated eggs are discharged in the biliary
ducts and in the stool
Eggs are ingested by a suitable snail
intermediate host
miracidia sporocysts rediae
cercariae
The cercariae are released from the snail
 

32. Cl. si. Conti.
Then, they come in contact and penetrate the
flesh of freshwater fish, where they encyst as
metacercariae
 
humans acquire infection by ingestion of
undercooked, salted, or smoked freshwater fish
After ingestion, the metacercariae excyst in the
duodenum and ascend the biliary tract

33. Life cycle of C.sinesis

34. Cl. si. Conti.
Clinical feature and pathology
Major symptoms are diarrhea, jaundice,
cirrhosis, biliary obstruction, hepatomegally
Laboratory Diagnosis
1.Finding the eggs in the faeces
2. Finding the eggs in aspirates of duodenal
fluids

35. Cl. si. Conti.
3. Serological diagnosis
Antibody or antigen detection
Treatment : praziquantel
Prevention and Control
1.Avoid eating raw fish

36. Cl. si. Conti.
2.Sanitary disposal of faeces and not using
faeces as a night soil
3. Destroy the snails
4. Inspection of fish
5.Treating infected person and giving health
education

37. Opisthorchis viverrini
Endemic in mekong River basin in Thailand,
Cambodia ,Ukraine & Russia
Transmission & life cycle are similar to
C.sinensis
Fish eating animals like dogs & cats serve as
reservoir host
Mature fluke live in biliary and pancreatic
duct

38. Op. vi. conti
The fluke and deposited egg causes
inflammation & fibrosis around the bile
duct
Diarrhea , flatulence , abdominal
pain ,enlargement of liver , jaundice
Laboratory diagnosis , prevention &
control are similar to C.sinensis

39. Opisthorchis felineus
Common parasites of cats , dogs , fish
eating wild animals & also infects
humans
Mainly found in Russia Kazakhstan,
Ukraine & Poland
The life cycle ,clinical features, laboratory
diagnosis , prevention &control are
similar to C. sinensis

40. Op. fe. conti
Egg

41. Intestinal Flukes
General Characteristics
Adults live in the intestine
Eggs are large and contain
undeveloped ovum when passed in the
faeces
They are hermaphrodite

42. Intestinal Flukes
Include
Fasciolopsis buski
Heterophyes heterophyes
Metagonimus yokogawai
Gastrodiscoides homines

43. Fasciolopsis buski
Common name : Giant intestinal fluke
Geographical Distribution :China, Taiwan,
Thailand, Vietnam, Indonesia
Habitat
Adults: small intestine of man , pig, dog,
Eggs: In the faeces of man, Pig, dog,
Larval forms: Fresh water snails
Metacercariae: encysted on certain aquatic
vegetation

44. Fa. bu. conti.
Morphology
Adult
Size: 20-75mm by 8-20mm
Large, fleshy, flat worm
Has no cephalic cone &
shoulder

45. Fa. bu. conti.
Egg
Size: 130-140m by 80-85m
Colur : Pale yellow-brown
Shape: oval
Small operculum
Unembroynated
 

46. Fa. bu. conti.
Egg

47. Fa. bu. conti.
Life cycle
Immature eggs are discharged into the
intestine and stool
Eggs become embryonated in water , eggs
release miracidia , which invade a
suitable snail intermediate host
sporocysts rediae cercariae

48. Fa. bu. conti.
 The cercariae are released from the snail and
encyst as metacercariae on aquatic plants
The mammalian hosts become infected by
ingesting metacercariae on the aquatic plants
after ingestion, the metacercariae excyst in the
duodenum and attach to the intestinal wall
 There they develop into adult flukes  

49. Life cycle of Fasciolopsis buski

50. Fa. bu. conti.
Clinical feature and Pathology
Epigastric pain, nausea and diarrhea
 In heavier infections, generalized edema
and ascites occur
The fluke attaches itself to the intestinal
mucosa where inflammation, ulceration
and abscesses occur

51. Fa. bu. conti.
Laboratory Diagnosis
1.Finding eggs in the faeces
2. Finding adult worms in the faeces
occasionally
Treatment
Praziquantel

52. Fa. bu. conti.
Prevention and Control
1.Avoid eating uncooked water plants which
may be infected
2.Construction of latrine
3. Avoid use of human faces as a fertilizer

53. Fa. bu. conti.
3. Destroy snails and their habitat
4. Treating infected individuals and
giving health education

54. Heterophyes heterophyes
Geographical Distribution: China,
Japan, Egypt, Korea, Taiwan
Habitat
Adult: In small intestine of man, cat, dog,
fox
Egg : In the faeces
Larval forms: In fresh water snails
Metacercariae: fresh water fish

55. Het. he. Conti.
Morphology
Adult: Size: 1-2mm;has three
suckers :oral, ventral & genital suckers
Egg: Similar to the egg of Clonorchis
sinensis
Shell: Slightly thicker than
Clonorchis
sinensis

56. Het. he. Conti.
Life Cycle
 embryonated eggs ,each with a fully-
developed miracidium, are passed faeces
After ingestion by a suitable snail , the
eggs hatch and release miracidia which
penetrate the snail’s intestine (Genera
Cerithidia & Pironella  
 sporocysts rediae cercariae  

57. Het. he. Conti.
The cercariae are released from the snail
&encyst as metacercariae in the tissues of
a fresh water fish
The definitive host becomes infected by
ingesting undercooked or salted fish
containing metacercariae
After ingestion, the metacercariae excyst,
attach to the mucosa of the small intestine
& mature into adults

58. Life cycle of H.hetrophyes

59. Het. he. Conti.
Clinical features and pathology
Light infection usually asymptomatic
Heavy infection may cause diarrhea,
abdominal pain and eosinophilia
Laboratory Diagnosis
Finding of eggs in the faeces

60. Het. he. Conti.
 Treatment
Praziquantel
Prevention and Control
 Similar as Clonorchis sinensis
Reading assignment
Metagonimus yokogawai
Gastrodiscoides homines

61. Lung Fluke
Paragonimus westermani
Common name : Oriental lung fluke
Geographical Distribution
Extensively distributed in the Far East &
West African countries : Zaire, Nigeria,
Cameroon & South America

62. Par. we. Conti.
Habitat
Adults: In the lung of man
Eggs: In the sputum of man
Larval forms: Fresh water snails
Metacercariae: Fresh water crabs &
crayfish

63. Par. we. Conti.
Morphology
Adult: Size: 7.5mm-12mm by 4-
6mm
Egg
Size: 70-100m by 50-65m
Colour: Yellow-brown or brown
Shape: oval but asymmetrical
Has flattened operculum

64. Paragonimus westermani egg

65. Par. we. Conti.
Life cycle
eggs are excreted unembryonated in the sputum,
or alternately they are swallowed & passed with
stool
In the external environment, the eggs become
embryonated & miracidia hatch & penetrate
its soft tissues snail
sporocysts rediae cercariae
The cercariae invade a crustacean such as a crab
or crayfish, where they encyst & become
metacercariae

66. Par. we. Conti.
 Human infection with P. westermani occurs by
eating inadequately cooked crab or crayfish that
harbor metacercariae
The metacercariae excyst in the duodenum ,
penetrate through the intestinal wall into the
peritoneal cavity
 then through the abdominal wall & diaphragm
into the lungs, where they become encapsulated
& develop into adults

67. Par. we. Conti.
The worms can also reach other organs
and tissues, such as the brain and striated
muscles
 when this takes place completion of the
life cycles is not achieved, because the eggs
laid cannot exit these sites
 Animals such as pigs, dogs, and a variety
of feline species can also harbor P.
westermani.
 

68. Life cycle of P.westermani

69. Par. we. Conti.
Clinical feature and pathology
Light to moderate infection are
asymptomatic
Symptoms sever pulmonary
paragonimiasis: chest pain , cough, night
sweets, pleural effusion, & coughing up
blood
Worms may migrate to the brain where
they lay eggs and cause a granulomatous
abscess resulting in symptoms similar to
epilepsy

70. Par. we. Conti.
Laboratory Diagnosis
1.Finding of eggs in the sputum
sputum is usually bloody, mucoid &rusty
brown
2. Finding of eggs in aspirates of pleural
fluid & occasionally in faeces
Treatment
Praziquantel

71. Par. we. Conti.
Prevention and Control
1.Avoid eating raw or uncooked crabs &
crayfish
2.Avoid contamination of water with
sputum or faeces
3.Destroy snails & their habitat

72. Par. we. Conti.
4.Inspecting crabs & crayfish for
metacercariae
5.Treating infected individuals & giving
health education