Dorso-ventrally flat
Unsegmented
With integument
With holes in their
body Suckers
(oral/ventral)
Shape:
- flat, leaf – like in shape,
lanceolate, spatulate
- slender anteriorly & broad
posteriorly
Sex:monoecious
(hermaphrodite) except the
Schistosomes which are
diecious
Adult forms are oviparous
Oral sucker
Sex:monoecious
Esophagus
Morphology
Pharynx
Intestinal
ceca
Ventral sucker
Male
Ovary
Female Flame cells
Testes
Excretory bladder
Excretory pore
Ovaare operculated, EXCEPT the
Schistosomes which are non-
operculated but spinous
Ova
OPERCULATED
EMBRYONATED
NON-EMBRYONATED
NON-OPERCULATED
EMBRYONATED
SPINOUS
Operculated, Operculated, Non-
non- embryonated operculated,
embryonated embryonated
F. hepatica C. sinensis S. japonicum
F. buski O. felineus S. mansoni
E. ilocanum H. heterophyes S. hematobium
P. westermani M. yokogawai
H. yokogawai
Types of Cercaria Parasite
Lophocercus simple F. hepatica, F. buski, E.
tailed ilocanum
Lophocercus keel C. sinensis, O. felineus, H.
tailed heterophyes, M. yokogawai,
H. yokogawai
Microcercus P. westermani
Fork tailed S. japonicum, S. mansoni, S.
hematobium
Clonorchis Schistosoma
Cercaria sinensis japonicum
Opistorchis Schistosoma
felineus mansoni
Heterophyes Schistosoma
flukes hematobium
Lophocercus,
simple tailed
Fork
Lophocercus, tailed
keel tailed
Fasciola
hepatica
Fasciolopsis
buski
Echinostoma Microcercus
ilocanum Paragonimus
westermani
requires
2 intermediate hosts to
complete the life cycle EXCEPT
Schistosomes that require 1
intermediate host
Intermediate Hosts Parasite
Snail- aquatic F. hepatica, F.buski
vegetation
Snail-fish C. sinensis, O. felineus, H.
heterophyes, M. yokogawai,
H. yokogawai
Snail-snail E. ilocanum
Snail-crabs or P. westermani
crayfish
Snail only S. japonicum, S. mansoni, S,
hematobium
The infective stage of all
Trematodes metacercaria
EXCEPT Schistosoma spp fork-
tailed cercaria
Sporocyst – Redia – cercaria
Clonorchis sinensis
Opistorchis felineus
Paragonimus westermani
Sporocyst – redia I – redia II –
cercaria
Fasciola hepatica
Fasciolopsis buski
Sporocyst– redia – cercaria /
Sporocyst – redia I – Redia II –
cercaria
Heterophyes heterophyes
Metagonimus yokogawai
Haplorchis yokogawai
Redia I – redia II – cercaria
Echinostoma ilocanum
Sporocyst I – sporocyst II –
cercaria
Schistosoma japonicum
Schistosoma mansoni
Schistosoma hematobium
A. S–R–C
B. S – R1 – R2 – C
C. R1 – R2 – C
D. S1 – S2 – C
C. Sinensis
O. Felineus
O. Viverrini
H. Heterophyes S. Japonicum F. Hepatica
E.
M. Yokogawai P. Westermani
S. mansoni F. buski
H. yokogawai E. ilocanum
S. haematobium
INTESTINAL CECA
Simple C. sinensis, O. felineus,
E. ilocanum, H.
heterophyes, M.
yokogawai, H.
yokogawai
Simple, zigzag pattern P. westermani
Branched F. hepatica, F. buski
VITELLARIA
Branched F. hepatica, F. buski, P.
westermani
Delicately granular C. sinensis
Medium-sized E. ilocanum
Transversely O. felineus
compressed
Large, polygonal H. heterophyes, M.
yokogawai, H. yokogawai
Intestinal ceca
Vitellaria/Vitelline follicles
TESTES
Branched, one on top of the other F. hepatica, F. buski, C.
sinensis
Irregularly lobulated (side by side) P. westermani
Deeply lobular, one on top of the E. ilocanum
other
Lobular, obliquely arranged to O. felineus
each other
Spherical, unequal size, lying side H. heterophyes
by side
Ovoid, unequal size, lying side by M. yokogawai
side
Single, spherical testes H. yokogawai
OVARY
Ovoid E. ilocanum
Spherical/globular H. heterophyes, M.
yokogawai, H. yokogawai
Branched F. hepatica, F. buski
Lobular C. sinensis, O. felineus,
P. westermani
Testes
Ovary
Ingestion of improperly cooked
2nd intermediate host containing
the metacercaria
Skin penetration by fork tailed
cercaria
Fasciola hepatica
Clonorchis sinensis
Liver Flukes Opistorchis felineus
Intestinal Flukes Opistorchis viverrini
Lung Fluke
Blood Flukes Fasciolopsis buski
Echinostoma ilocanum
Heterophyes heterophyes
Metagonimus yokogawai
Haplorchis yokogawi
Schistosoma japonicum
S. haematobium
S. mansoni
Paragonimus westermani
PARASITE COMMON NAME
Fasciola hepatica Sheep liver fluke
Clonorchis sinensis Oriental or Chinese liver fluke
Opistorchis felineus Cat liver fluke
Opistorchis viverinni
Fasciolopsis buski Giant intestinal fluke
Echinostoma ilocanum Garrison’s fluke
Heterophyes heterophyes von Siebold’s fluke
Metagonimus yokogawai Yokogawa’s fluke
Haplorchis yokogawai
Fasciola
hepatica
Clonorchis sinensis
Paragonimu
s
wesermani
Fasciolopsis
buski
F. C. sinensis O. felineus O.
hepatica viverrini
Common Sheep liver Chinese liver Oriental liver
name fluke fluke fluke
Distribu- South China, Korea China, Korea Thailand
tion America
Disease Fascioliasis Clonorchiasis Opischloriasis
Infective Metacer- Metacercaria metacercaria Metacer-
stage caria caria
MOT ingestion ingestion ingestion ingestion
Habitat Proximal Distal biliary Distal biliary
biliary passage passage
passage/
liver
LIVER FLUKES
Parasite Common Name Disease
Produced
Fasciola Sheep liver fluke Fascioliasis
hepatica Temperate liver Sheep Liver
fluke Rot
Clonorchis Chinese liver fluke Clonorchiasis
sinensis Oriental liver fluke
Opistrochis Cat liver fluke Opistorchiasis
felineus felineus
Opistorchis Opistorchiasis
viverrini viverrini
Found in the liver & biliary
passages
2 species:
- F. hepatica – temperate liver
fluke
-F. gigantica – tropical liver fluke
Duodenum
Visceral cavity
Glisson’s capsule
Liver parenchyma
Hepatic duct
Proximal biliary
passage
Gall bladder
Pancreatic
duct
Blood vessel
Soft tissues, Skin
Lungs
1st intermediate host snails
(Lymnaedae)
- L. philippinensis
- L. auricularia rubiginosa
2nd
intermediate host aquatic
plants
- Ipomea obscura (kangkong)
- Nasturtium officinale
(watercress)
Trapa spp.
Kangkong
2nd Intermediate Hosts
Watercress Kangkong
Distribution
– Central and Latin
America, South America, Middle
East, France, England, etc.
2 stages:
1. Acute/ invasive stage – larval
migration & worm maturation in
the liver tissues
2. Chronic stage – persistence of
Fasciola worms in the biliary
ducts
Period of liver invasion trauma &
necrosis
Can be asymptomatic bile ducts
acute symptoms (2-6wks)
dyspepsia, fever, N & V, RUQ pain
Clinical triad high fever,
hepatomegaly, marked eosinophilia
Worm may cause obstruction
inflammation of biliary epithelium
fibrosis less bile passed out
Heavy infections atrophy of
liver & cirrhosis worm re-enter
liver abscess
Halzoun or Marrara
Due to ingestion of raw fasciola-
infected liver fluke survive
mastication attach to posterior
pharynx hemorrhagic
nasopharyngitis & dysphagia
Cholelithiasis
Hemobilia
Biliary
cirrhosis
Acute pancreatitis – rare
Extrahepatic sites (lungs, brain,
subcutaneous tissue, orbit)
abscess or fibrotic lesions
Skin migratory purpuric &
painful subcutaneous nodules up
to 6 cms
brain,
orbit, lungs, heart etc.
abscess formation
Liver involvement
Skin involvement
Halzoun/Marrara
Ductal epithelial hyperplasia,
Marked destruction and
infiltration, dilatation and
inflammation of liver tissue,
periductal fibrosis
capsular hematoma, and pockets
Biliary obstruction: cholecystitis,
of abscesses to fibrosis.
cholangitis and cholelithiasis
Subcutaneous nodules
associated with erratic
migration of juvenile
Fasciola hepatica
Stoolexamination
Serodiagnosis
Imaging
Praziquantel
Bithionol
Triclabendazole
Health education
Proper hygiene & sanitation
Protection of watercress beds
Thorough cooking of vegetables,
boiling of water
Anti-molluscicides to destroy snail
hosts
Acute viral hepatitis
Schistosomiasis
Visceral toxocariasis
Biliary tract diseases
Hepatic amoebiasis
Parasites of the bile duct &
gallbladder of humans & fish-
eating animals
There are many fish species that
can serve as intermediate host
most common Cyprinidae
Distribution:
Southeast Asia,
China, Korea, Taiwan etc.
Distribution:Central, eastern and
Southern Europe, USSR, Siberia,
Far East: Japan, Korea,
Philippines, Vietnam, India,
Hongkong
Opistrochis
felineus
Clonorchis
sinensis
2nd Intermediate
Hosts
Pickled fish
Smoked fish
Salted fish
Dried fish
Raw fish
Duodenum
Sphincter of
Oddi
Distal biliary
Passage
Hepatic duct
Gall bladder
Pancreatic
duct
Gross picture of adult
worms, liver tissue and
x-section of thickened
ducts
X-section of the dilated
biliary duct containing 2
adult worms within the
lumen of the duct with
proliferation of the
epithelial lining
X-section of the biliary duct with adult
worm. Note enlarged, dilated, tortuous
thickening of the duct with proliferated
epithelial lining
Acute phase:
• Appears 10 – 26 days after
ingestion of infected fish
• Low grade fever, anorexia,
diarrhea, enlarged tender liver
• hepatic or epigastric pain
Flatulence & indigestion
Increasing worm burden low
grade fever, progressive
hepatomegaly, RUQ tenderness,
intermittent RUQ & epigastric
pain, gall bladder dilatation &
dysfunction, weakness, anorexia
& diarrhea
Consideration:
• Leukocystosis
• eosinophilia
Eggs (-) in the feces 3 to 4 weeks
after onset
Cholelithiasis
Pyogenic cholangitis
Biliary obstruction
Abscess formation
Mild to severe pacreatitis
Cholangiocarcinoma (high in
Opistrochiasis)
Hepatocellular carcinoma (high in
Clonorchiasis)
1.Stool examination,
duodenal or biliary
aspirate
2.Serology
3.Imaging of the liver
4.Histopathology of
malignant growth
F. C. sinensis O. O.
hepatica felineus viverrini
Ova Operculated, Operculated Same as Same
non- embryonated Clonorchis
embryonated (old bulb)
(hen’s egg)
I. Host Snail-aquatic Snail- fresh Same as Same
combina- vegetation brackish Clonorchis
tion water fish
Type of Lophocercus, Lophocercus, same same
cercaria simple tailed keel tailed
Intramollus- S-R1-R2-C S-R-C or S- same same
can dev’t R1-R2-C
F. C. sinensis O. O.
hepatica felineus viverrini
Pathology Epithelial & Epithelial & Epithelial &
endothelial endothelial endothelial
proliferation proliferation, proliferation,
- cystic cystic cystic
dilatation of dilatation of dilatation of
biliary biliary biliary
passages passages passages
Other - abscesses HepatoCA > HepatoCA <
Pathology in the liver cholangio- cholangio-
- Halzoun carcinoma carcinoma
- Reddish
nodule in SC
tissues &
skin
F. C. sinensis O. O.
hepatica felineus viverrini
S/S RUQ pain, fever, RUQ pain, RUQ pain,
jaundice, easy Jaundice, Jaundice,
fatigability fever, easy fever, easy
- Halzoun fatigability fatigability
- Painful skin - S/S - S/S
nodule/indura- associated associated
tion with with with
swelling malignancies malignancies
Lab. Hx & PE Hx & PE Hx & PE
dx Stool exam Stool exam Stool exam
Serology Serology Serology
Imaging of liver Imaging of Imaging of
liver liver
Histopath Histopath
F. C. sinensis O. O.
hepatica felineus viverrini
Treatment Triclaben- Praziquantel Praziquantel
dazole
Bithionol
Prevention - Hygiene & - Hygiene & same same
sanitation sanitation
- Health - Health
education education
- Protection - Cook fish
of H2Ocress thoroughly
beds Destroy snail
- Cook liver host Cu2So4)
adequately - Avoid using
-vaccination night soil as
fertilizer
