This document provides information on various liver and lung flukes that can infect humans and animals. It describes the key characteristics of seven different fluke species including Fasciola hepatica (sheep liver fluke), Fasciola gigantica (tropical liver fluke), Clonorchis sinensis (oriental liver fluke), Opisthorchis felineus, Opisthorchis viverrini, and Paragonimus westermani (oriental lung fluke). For each species it summarizes the definitive host, habitat, life cycle involving snail and fish intermediate hosts, epidemiology, pathology, diagnosis, treatment, and morphology of eggs and adult flukes.

1. Fasciola hepatica
“sheepliver fluke”
Fasciola gigantic
“Tropical liver fluke”
Clonorchis sinensis
“Oriental liver fluke”
Opisthorchis
felineus
Opisthorchis
viverrini
Paragonimus
westermani
“Oriental lungfluke”
Disease Fascioliasis, Sheep
liver rot
Fascioliasis Opisthorchiasis Paragonimiasis
Definitive host Sheep, cattle, deer,
rabbits, humans, &
other herbivorous
mammals
Cattle, w ater buffalo,
camels, w ild hogs,
humans & other
herbivorous mammals
Humans, hogs, dogs,
cat, w ildcat, martin,
badger, mink, & rarely
ducks
Cats, dogs, foxes,
hogs, & humans
Civet cat, dogs, cats,
humans & fish-eating
mammals
Humans, carnivores,
cats, dogs, aquatic
mammals, Mongoose,
opossums, & rats
Habitat Proximal bile
passages,
gallbladder, & ectopic
sites
Liver Common bile duct to
distal biliary ducts
Distal bile ducts & Pancreatic duct lungs
Primary IH 21 species of lymneid
snails
Snails Operculate snails
Alocinma &
Parafossarulus
Snails(Bulimus) Snails Operculated snails.
–Far east - Hua,
Semisulcospira,
Syncera, & Thiara
-North America –
Pomatiopsis
-South America &
Philippines- Pomacea
Antemelania (Brotia)
asperata &
Antemelania Dactylus
Secondary IH Aquatic plants Aquatic plants 40 sp of fresh water
fish
Cyprinoid fish Fish -Fresh w ater crabs-
Eriocheir, Potamon,
Sesarma,
-Parathelphusa in far
east,
Pseudothelphusa
-Crayfishes of
Astacus in Far east &
Cambarus in North
America
Metacercariae Migrate to biliary tree
& mature 12 w eeks
Penetrate liver
capsule & migrate to
biliary tree
Wall is dissolved in
the duodenum by
trypsin activated
larvalw ormmigrate to
common bile duct &
distal biliary ducts &
becomes an adult
w ithin a month
Mature in 3-4 w eeks Take 20 days to
reach the lungs.
Adult in 5-6 w eeks
Epidemiology
Sheep & cattle-raising
countries of the w orld
Cuba, southern
France, Great Britain,
Algeria & US
Africa, asia, & haw aii Far east Japan,
China, South Korea,
Formosa, & vietnam
Southeastern Europe
& Asiatic areas of
former USSR,
Endemic in Poland &
the Dnieper, Donetz &
Desna basins
Thailand, Laos,
Southeastern Asia
Japan, South korea,
Thailand, Taiw an,
Philippines, South &
southeast asia,
Indonesia, Isalnds of
south pacific &
northern south
america

2. Pathology -Necrotic liver tissue
-migrates through the parenchyma to the bile
ducts
-in bile ducts, provokes inflammatory &
adenomatous changes in the mucosa & cause
obstruction
-Severe headache, chills, fever, urticaria,
Stabbing substernalpain, right upper quadrant
pain that radiate to the back & shoulders may
be the first evidence of infection
-enlarged tender liver, jaundice, digestive
disturbances, diarrhea, eosinophilia, & anemia
Early infection:
leukocytosis &
eosinophilia. Bile
ducts thicken
gradually & become
dilated & tortuous.
Fibrosis & destruction
of hepatic
parenchyma takes
place liver function is
impaired SGOT &
SGPT serum levels
are normal
Heavy infections:
Cholelithiasis &
pyrogenic cholangitis
Similar to C. sinensis -Similar to C. sinensis
-Association w/
cholangiocarcinoma
-Fibrous tissue
capsule in lungs. Cyst
is blood-tinged,
purulent material
containing eggs
-Rusty brow n sputum
-Pulmonary pain &
pleurisy
-Hemoptysis
-Difficult to separate
this infection fromTB,
pneumonia or
bronchiectasis
-in brain: Jacksonian
epilepsy, Hemiplegia,
monoplegia, paresis
of varying degree
-Worms in
Subcutaneous
tissues: creeping
tumors
-Prognosis good in
light infections
-Prognosis
unfavorable in Heavy
infections w / cerebral
involvement
Lab dx -Finding eggs in
feces or bile. Eggs
may not appear in
feces until3-4 months
after metacercariae
ingestion
-(+) complement
fixation test &
intracutaneous rxns
w / Fasciola antigens
-RFLP assay using
common restriction
enzyes Ava II & Dra II
differentiate the 2
Fasciola sp
Finding eggs in feces Finding eggs in feces/biliary drainage -Finding eggs in feces
or duodenal aspirates
-Ultrasonography
usefulin screening
presence of
cholangiocarcinoma
-Blood tinged sputum,
eosinophilia
-radiographs aid in dx
-eggs in sputum
added w / 3%
NaOH(decongestant
& decontaminant)
-Intradermal Test
-Complement fixation
(CF) standard
serologic test, high
sensitivity for dx &
assessment of cure
after therapy
-Enzyme
immunoassay (EIA) –
replace CF
-Immunoblot (IB) 99%
sensitivity used by
CDC since 1988
Tx Dichlorophenol (bithionol) Praziquantel Praziquantel Praziquantel Praziquantel
Corticosteroids
Bithionol

3. Triclabendazole
Morpholody Life span: 10 years
Egg- 130-150x63-
90um Large oval
yellow ish-brown
operculated
Unsegmented at
oviposition
Adult fluke- Large w/
flat leaf shape &
characteristic
shouldered
appearance fromits
cephalic cone
-20-30x8-13mm
-oral& ventral
suckers are of equal
size on cephalic cone
-Intestine w /
numerous diverticula
-High dendtritic testes
in tandem formation
-Branched vitellaria in
lateral & posterior
portions of the body
-Short convoluted
uterus
Egg- 150-190x70-
90um
Adult fluke-Similar to
F. hepatica but
longer, shorter
cephalic cone, large
ventralsucker, &
more anterior position
of reproductive
organs
-Shoulders are less
developed
-ceca are more
branched & branches
of the ovary are
longer & more
numerous
Egg-29x16um light
yellow ish-brown
-operculumrests in a
rim w / distinct
shoulders
-contour doesn’t
follow curvature of
shell
-thicker posterior end
w / small median
protruberance
-Fully developed
miracidia doesn’t
hatch readily in w ater
Adult fluke- flat
elongated, aspinous,
flabby, opalescent
gray w ormtapering
anteriorly & rounded
posteriorly12-20x3-
5mm
-Ventralsucker
smaller than oral
sucker lying ¼ length
of the body from
anterior end
-Long intestinal ceca
extending to posterior
end
-Deeply lobed testes
in tandem formation
-Small lobate overy
anterior to testes in
midline
-loosely coiled uterus
ending in common
genital pore-minutely
follicular vitellaria in
lateral midpoint of
body
Egg- 30x12um
narrow er& more
tapered end than C.
sinensis. A pointed
terminal knob & less
conspicuous
opercular rim
Adult fluke-
Resemble C. sinensis
Egg- 26x13um
resembles C.
sinensiss
Adult fluke Similar to
O.felineus
Egg- 85x55um
Yellow ish-brown thick
shell & thickened
opercular rim
Unembryonated at
oviposition
Adult fluke- Spoon-
shaped w hen active &
Oval, flattened coffee
bean w hen contracted
or preserved
8-16x4-8
-spinous cuticle
-Suckers are of equal
size. Ventral sucker
just anterior to
equatorial plane
-posterior 4rd of the
body
-Lobed ovary anterior
to testes on right side
opposite closely
coiled uterus
-Vitellaria in extreme
lateral fields for entire
length of body