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TREMATODES
PHYLUM :
CLASS :
PLATYHELMINTHES
TREMATODA
INTESTINAL FLUKE : Fasciolopsis, Heterophyes
LIVER FLUKE
: Fasciola, Clonorchis, Dicrocoelium
LUNG FLUKE
: Paragonimous
BLOOD FLUKE
: Schistosoma
TREMATODES AS ENDOPARASITES
Infective stage from the life cycle of parasite
Disease caused and its symptoms
Diagnosis of the disease
INTESTINAL FLUKES
1. Fasciolopsis
2. Heterophyes
FASCIOLOPSIS
∞Central and Southeast Asia
∞Elongate oval fluke
∞2 to 7 cm long
LIFE CYCLE OF FASCIOLOPSIS
Fasciolopsis
ORGAN AFFECTED
Small Intestine
DISEASE NAME
Fasciolopsiasis
INFECTIVE STAGE TO
HUMAN
Metacercaria
SYMPTOMS
Chronic Diarrhoea, Asthenia, Mild
Anaemia, Eosinophilia and Oedema
PATHOLOGY
Attaches itself to the intestinal mucosa
causing inflammation, ulceration, abscesses
DIAGNOSIS
Eggs in faeces
TREATMENT
Praziquantel (Single dose of 75 mg/kg/day
in 3 divided doses for one day).
Mode of Action of Praziquantel
Praziquantel
Permeability of calcium
ion increases in the cell
membrane of parasite
Paralysis of musculature
of parasite
Destroyed by host immune
reaction i.e. Phagocytosis
Disturbances
oviposition
Interfere
with
adenosine uptake
Unable to synthesize
purines such as
adenosine.
of
Side effects
Direct effects
Abdominal discomfort , particularly pain and nausea,
diarrhoea, headache, dizziness, and drowsiness may occur
shortly after taking Praziquantel;
These direct effects are transient and dose-related.
Indirect effects
Fever, Pruritus, Urticaria, Rashes, Arthralgia, and Myalgia
are noted occasionally and increase in Eosinophilia often
relate to parasite burden.
Heterophyes
Adult of H. heterophyes,
stained with carmine. In
this figure, the following
structures are labeled: oral
sucker (OS), pharynx (PH),
intestine (IN), ventral
sucker, or acetabulum (AC),
and eggs within the uterus
(UT).
Common in North Africa, Asia minor , Korea , China, Japan,
Taiwan, and the Philippines
Infection is acquired by eating raw fish, a common food in
coastal areas
LIFE CYCLE OF HETEROPHYES
Heterophyes
ORGAN AFFECTED
Small Intestine
DISEASE NAME
Heterophyiasis/ dwarf fluke infection.
INFECTIVE STAGE TO
HUMAN
Metacercaria
SYMPTOMS
Peptic ulcers, upper abdominal discomfort,
gurgling abdomen
PATHOLOGY
Causes a mild inflammatory reaction at its
site of contact with the intestine but in
heavy infections cause damage to
the mucosa.
DIAGNOSIS
Eggs in feces
TREATMENT
Niclosamide
Praziquantel (a single dose 20mg/Kg for 3
days)
Mode of action:
The adult worms are rapidly killed, presumably due to
inhibition of oxidative phosphorylation.
Side effects:
Diarrhea, anorexia, nausea and vomiting.
Skin rashes or urticaria
Contraindications and precautions: Safety of the drug has
not been established in children under 8 years of age.
LIVER FLUKES
Fasciola
Clonorchis
Dicrocoelium
Fasciola
Found in Rural areas of temperate and tropical regions
Adult has a flat leaflike body
About 20-30 mm long by 8-15 mm wide
Has an anterior elongation where oral and ventral
suckers are located
LIFE CYCLE OF FASCI0LA
Fasciola
ORGAN AFFECTED
Liver
DISEASE NAME
Fascioliasis
INFECTIVE STAGE TO
HUMAN
Metacercaria
SYMPTOMS
Vomiting, persistent diarrhoea, jaundice, with
peripheral eosinophilia
PATHOLOGY
Immature flukes migrate through the liver
parenchyma for 6-8 weeks giving rise to a
tender hepatomegaly
DIAGNOSIS
Yellow-brown eggs in the stool
TREATMENT
Bithionol
Triclabendazole
Mode of action
Impairs egg
formation
Interferes with the neuromuscular
physiology of helminths
Defects
cuticle
covering
in
Decreases glycolytic and oxidative metabolism (succinate oxidation inhibited
)
Side effects
• Diarrhea accompanied by anorexia, nausea and vomiting.
• Skin rashes or urticaria
Mechanism of action
 Inhibition of the parasites motility, probably related
to the destruction of the microtubular structure,
resulting in the death of the parasite.
 Inhibiting the release of proteolytic enzymes, a
process that appears critical to the survival of the
parasite.
Side effects
Gastrointestinal disturbances (abdominal cramps;
diarrhea).
• The Chinese liver fluke is distributed in Asia (Far East region).
• The infections result from eating raw or half-cooked fresh
water fish and shrimps
• Eggs looks like a sesame seed under the low power and a water
melon seed under the high power
Parafossarulus anchouricus
Bithynia longicornis
Melanoides tuberculata
Semisulcospira libertina
Assiminea lutea
Tarebia granifera
ORGAN AFFECTED
Liver (mainly in bile duct and gall bladder)
DISEASE NAME
Clonorchiasis (biliary cirrhosis)
INFECTIVE STAGE TO
HUMAN
Metacercaria
SYMPTOMS
Ascites, splenomegaly, anemia, coma
PATHOLOGY
Bile is stored increasingly in hepatic cells and
diffuses between them.
Degeneration of local hepatic cells.
Necrosis of local hepatic cells.
DIAGNOSIS
Eggs in faeces
TREATMENT
Triclabendazole, Praziquantel (75mg/kg/day
in 3 divided doses for one day),Bithionol,
Albendazole (10 mg/kg orally once a day for
7 days)
Binding to the colchicinesensitive site of tubulin
Degenerative changes in the
ER and mitochondria
Inhibition of microtubule
polymerisation
Release of lysosomes
Alterations in the tegument
and intestinal cells of the
worm
Decreased production of ATP
Impaired glucose uptake by
the larval and adult stages
and glycogen stores depletion
Parasite is immobilized and
eventually dies
Side Effects
• Mild and transient epigastric distress, diarrhea,
headache, nausea, dizziness, and insomnia can occur.
• In long-term use it can cause abdominal distress,
headaches, fever, fatigue, increases in liver enzymes
and pancytopenia.
Dicrocoelium
Due to the highly specific nature of this parasite’s life cycle, human
infections are generally rare
Endemic or potentially endemic in 30 countries
Cochlicopa lubrica
Dicrocoelium
ORGAN AFFECTED
Bile ducts of humans
DISEASE NAME
INFECTIVE STAGE TO
HUMAN
Metacercaria
SYMPTOMS
Bloating and diarrhea
PATHOLOGY
Enlarged liver (hepatomegaly) or
inflammation of the liver (cirrhosis)
DIAGNOSIS
Eggs in faeces
TREATMENT
Praziquantel, Triclabendazole
LUNG FLUKES
Paragonimous
Paragonimous
The adult stage might attain a length of up to 15 millimetres
Worldwide roughly 20 million people are infected with Paragonimus
Semisulcospira
Paragonimous
ORGAN AFFECTED
Lung
DISEASE NAME
Paragonimiasis
INFECTIVE STAGE TO
HUMAN
Metacercaria
SYMPTOMS
include abdominal pain, diarrhoea, fever, and
hives
PATHOLOGY
Bad cough, bronchitis, and blood in sputum
(hemoptysis),Ulcers in lungs
DIAGNOSIS
Eggs in faeces
TREATMENT
Praziquantel
BLOOD FLUKE
Schistosoma
Schistosoma
The
genus has been divided into four
indicum, japonicum, haematobium and mansoni
groups
-
S. haematobium
S. mansoni
S. japonicum
DISEASE D
ORGAN
Blood
Intestine
Intestinal and
hepatic
LOCATION
Venus plexus around
the urinary bladder
Mesenteric plexus
of Sigmoidorectal area
Mesenteric plexus of
ileo-caecal area
Haematuria and
fibrosis of the bladder,
Calcification of
bladder and
hydronephrosis.
Dysenteric attack,
ectopic lesions ,
haepatomegaly,
periportal
cirrhosis and
myelitis
Praziquantel
metrifonate
Praziquantel
oxamniquine
PATHOGENICI
TY
TREATMENT
Intestinal
granulomas
same as Schistosoma
haematobium
A
B
C
Mode of action
• It causes worms to shift from the mesenteric veins to the
liver
• The male worms are retained;
• The female worms return to the mesentery, but can no longer
release eggs.
• DNA synthesis inhibition
Side effects

The only significant common side effect reported is mild to
moderate dizziness with or without drowsiness, nausea, vomiting,
abdominal pain and diarrhoea.

More severe neuropsychiatric symptoms such as severe headache,
hallucinations, episodes of fainting, severe amnesia, total
disorientation in space and time and confusion have been rarely
reported.

Discoloration of the urine from orange to red may follow after the
drug treatment (most likely due to a metabolite).
Contraindications: Patients with pre-existing central nervous
system disturbances such as epilepsy or psychiatric disorders
should be treated with caution.
It is an organophosphorus compound used first as an insecticide
and later as an anhelminthic, especially for treating S.
haematobium
 Physical properties:
 Weight: 257
 Soluble in water
Chemical structure
Doses:
 7.5 to 10 mg/kg and a widely adopted schedule of 7.5 mg/kg,
given in three oral doses at an interval of 14 days.
Route of administration: Oral
Brand Name: Bilarcil, (Formulated as tablets containing 100 mg of
active substance)
Mechanism of Action
 It is a prodrug, at physiological pH, it is converted
nonenzymatically to dichlorovos.
 It is a potent cholinesterase inhibitor. This inhibition temporarily
paralysis the adult worms resulting in their shift from the bladder
venous plexus to small arterioles of the lungs, where they are
trapped encased by the immune system and die.
 This drug is not effective for the eggs of S. haematobium.
Side effects:
 Fatigue, muscular weakness, muscle tremor, sweating, fainting,
abdominal colic, diarrhoea, nausea, vomiting or bronchospasm.
 Contraindications:
 It should not be used after recent exposure to insecticides or drugs
that might potentiate cholinesterase inhibition.
 It is contraindicated in pregnancy.
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