Completely based on medical text books on parasitology.

2. CHARACTERISTICS
 Flat or fleshly, leaf-like unsegmented
body.
 Incomplete alimentary canal.
 Possess suckers with no hooks.
 Sexes are separate in Schistosomes,
while the others are hermaphroditic.
 Oviparous

3. GENERAL CHARACTERISTICS
 Presence of two suckers.
 Has no body cavity, circulatory and
respiratory organs.
 Alimentary system- mouth surrounded
by an oral sucker, muscular pharynx,
oesophagus which bifurcates into 2 blind
caeca (inverted Y shaped)
 Rudimentary nervous system – paired
ganglion cells.

5. CLASSIFICATION
 BLOOD FLUKES
 LIVER FLUKES
 INTESTINAL FLUKES
 LUNG FLUKES
BASED ON HABITAT:

6. BLOOD FLUKES
 Family : Schistosomatidae
 Genus : Schistosoma
 Species:
1. S. haematobium
2. S. mansoni
3. S. japonicum
4. S. mekongi
5. S. intercalatum

7. SCHISTOSOMES
 Schistosomiasis (bilharziasis)
 Water-borne disease (Africa, Asia & Latin
America).
 Male worm is broader & lateral border is
rolled ventrally into a cylindrical shape,
producing a long groove –
GYNECOPHORIC CANAL, inwhich
females are held.
 Live in venous plexus in body of definitive
host

8. Characteristics
 Dioecious
 Males are shorter and stouter than females
 Lateral margins of males are folded ventrally to form a
gynecophoral canal in which females are received
 Suckers are armed with delicate spines
 There is no muscular pharynx
 Eggs are non-operculated
 Eggs are fully embryonated when laid
 Embryonated eggs have a ciliated embryo called
miracidium
 Cercariae have bifid tails
 There is no encysted metacerciarial stage
 Infective Stage: cercaria penetrating the unbroken skin

9. BLOOD FLUKES: SCHISTOSOMAS
 Schistosoma japonicum: Oriental blood
fluke
 Schistosoma haematobium: Vesical
blood fluke
 Schistosoma mansoni: Manson’s blood
fluke

10. Features distinguishing Schistosomes
from other trematodes
 Unisexual.
 Lack muscular pharynx
 Intestinal caeca reunite after bifurcation
to form a single canal.
 Produce non-operculated eggs.
 Cercariae have forked tails and infects
by penetrating unbroken skin of
definitive host.

11. SCHISTOSOMA HAEMATOBIUM

12. HISTORY & DISTRIBUTION
 Bilharzia haematobium.
 Bilharz described about the adult worm.
 Endemic in most parts of Africa, West
Asia some parts of India.

13. MORPHOLOGY

14. ADULT WORM FEMALE
20mm long,
0.25mm thick with
cuticular tubercles
confined to ends.
GYNECOPHORIC
CANAL
MALE
10-15mm long, 1mm
thick & covered by
finely tuberculated
cuticle
SUCKERS

15. EGG
Ovoid non-operculated Gravid worm has
20-30 eggs in
uterus at a time &
realises 300
Eggs/day
With a brownish yellow
transparent shell
carrying terminal
spine at one pole

16. Life Cycle
 Definitive host : Humans
 Intermediate host : freshwater snails
 Infective form : Cercaria larva

18. CLINICAL FEATURES
 Classified depending on stages in
evolution of infection:
o During incubation period
o During oviposition
o During tissue proliferation & repair

19. 1.Skin penetration & Incubation
period
 Local cercarial
dermatitis/Swimmer’s
itch – transient itching
and petechial lesions at
site of entry of cercariae.
o Often in visitors to endemic
areas than locals
 Anaphylactic or toxic
symptoms – fever,
malaise and urticaria.
 Accompanied by
leucocytosis, eosinophilia,
enlarged tender liver

20. 2.Oviposition
 Painless terminal hematuria – initially
microscopic later becomes gross.
 Develops frequency of micturition and
burning.
 Cystoscopy – hyperplasia and
inflammation of bladder mucosa.

21. 3.Tissue proliferation and repair
 Generalised hyperplasia & fibrosis of vesical
mucosa with granular appearance – sandy
patch.
 Pseudo abscesses – d/t dense infiltration
with inflammatory cells at site of deposition of
eggs.
 Chronic cystitis – secondary bacterial
infection.
 Calculi formation d/t deposition of oxalate
& uric acid crystals around eggs.
 Obstructive hyperplasia of ureters & urethra.
 Associated Squamous cell carcinoma.

22. LAB DIAGNOSIS
 Detection of egg:
o Urine microscopy
o Bladder mucosal biopsy
 Detection of antigen:
o Circulating anodic antigen & Circulating cathodic
antigen by ELISA
 Detection of antibody:
o Complement Fixation Test (CFT)
o Immunofluorescence
o Indirect Hemagglutination
o Bentonite flocculation test
o Enzyme linked immunoelectrotransfer blot
o FAST/ELISA

23.  Intradermal skin test(Fairley’s test):
o Group specific test gives positive to all
Schistosomiasis
 Imaging:
o X-Ray- bladder and ureteral calcification.
o USG-hydroureter & hydronephrosis
o Indirect diagnosis: IVP & Cystoscopy

24. TREATMENT & PROPHYLAXIS
 DOC – Praziquantel (40mg/kg for 1 day)
 Alternative DOC – Metriphonate
 Prophylaxis:
o Eradication of intermediate molluscan hosts.
o Prevention of environmental pollution with urine and
faeces.
o Effective treated of infected.
o Avoid swimming, bathing and washing in infected
water.

25. SCHISTOSOMA MANSONI

26. HISTORY & DISTRIBUTION
 Manson discovered eggs with lateral
spines in the feces of a west indian
patient that led to the recognition of this
second species of human schistosomes.
 It is widely distributed in Africa, South
America and the Carribean islands.

27. HABIT MORPHOLOGY
 Adult worm lives in the
inferior mesenteric vein.
 S. mansoni resembles S.
haematobium in
morphology and life
cycle, except:
 Adult worms are smaller
and their integuments
studded with prominet
carse tubercles.
 The prepatent period is 4-5
weeks.

28. LIFE CYCLE
 DEFINITIVE HOST: Humans are the
only natural definitive hosts.
 INTERMEDIATE HOST: Planorbid
freshwater snails of the genus
Biomphalaria.
 INFECTIVE FORM: Fork-tailed cercaria.

29. PATHOGENICITY AND CLINICAL
FEATURES
 CERCARIAL DERMATITIS:
 Following skin penetration by cercariae
 KATAYAMA FEVER:
 Formation of immune complexes. Signs and
symptoms include high fever, rash, arthralgia,
etc..
 INTESTINAL BILHARZIASIS:
 Microabscesses.
 Portal hypertension.

30. LABORATORY DIAGNOSIS
 Stool microscopy.
 Rectal biopsy.
 Serological diagnosis.
 Imaging.
 Blood examination.

31. TREATMENT & PROPHYLAXIS
 DOC – Praziquantel (40mg/kg for 1 day)
 Oxamniquine(single oral dose 15mg/kg)
is also effective.
 Prophylaxis:
o Eradication of intermediate molluscan hosts.
o Prevention of environmental pollution with urine and
faeces.
o Effective treated of infected.
o Avoid swimming, bathing and washing in infected
water.

32. SCHISTOSOMA JAPONICUM

33.  COMMON NAME: Oriental blood fluke
 DISTRIBUTION: Far east, Japan, China..
 HABITAT: superior mesenteric vein, also
seen in the intrahepatic portal venules and
hemorrhoidal plexus of veins
 MORPHOLOGY:
 Adult male is comparatively slender(0.5mm
thick).
 Female lays upto 3500 eggs at one time.
 The prepatent period is 4-5 weeks.
 Eggs are smaller as compared to S.
haematobium and S. mansoni.

34. LIFE CYCLE
 Similar to S. haematobium, except;
 DEFINITIVE HOST: man
 INTERMEDIATE HOST: Amphibian snails of
the genus Oncomelania.
 INFECTIVE FORM FOR HUMAN: Fork
tailed cercaria.

35. PATHOGENICITY AND
CLINICAL FEATURES
 KATAYAMA FEVER.
 CHRONIC ILLNESS.
 CENTRAL NERVOUS SYSTEMAND
LUNGS INVOLVED.

36. TREATMENT & PROPHYLAXIS
 DOC – Praziquantel (40mg/kg for 1 day)
 Prophylaxis:
o Eradication of intermediate molluscan hosts.
o Prevention of environmental pollution with urine and
faeces.
o Effective treated of infected.
o Avoid swimming, bathing and washing in infected
water.

37. SCHISTOSOMA INTERCALATUM
 First noted in 1934 in West-Central
Africa.
 Eggs are fully embryonated without any
operculum. Eggs are acid-fast.
 Produces few symptoms involveing the
mesentric portal system.
 Diagnosis is established by detecting
the egg in feces and rectal biopsy.
 Praziquantel is the drug of choice.

38. SCHISTOSOMA MEKONGI
 First recognized in 1978 is found in
Thailand and Cambodia along the Mekong
river.
 Closely related to S. japonicum but is
slightly smaller and round.
 Man and dog are the definitive host.
 Man acquires infection in the same way as
in S. japonicum.
 Hepatosplenomegaly and ascites are the
common clinical finding.

39. HERMAPHRODITIC FLUKES:
LIVER FLUKES

40. FASCIOLA HEPATICA
 COMMON NAME: Sheep liver fluke.
 HISTORY & DISTRIBUTION:
 First trematode that was found more than 600
years ago in 1379 by Jehan de brie.
 Named by Linnaeus in 1758.
 Largest and most common liver fluke.
 Cause economically important disease “liver rot”
in sheep.
 F.gigantia is more prevalent in india than
F.hepatica.
 HABITAT: parasite resides in the liver and
biliary passages of the definitive host.

41.  MORPHOLOGY:
 Large in size, flat leaf-shaped fluke measuring 30mm
long and 15mm broad, gray or brown in color.
 Adult worm lives 5 years in sheep and 10 years in
humans.
 Has a conical projection anteriorly containing an oral
sucker and is rounded posteriorly.
 EGG:
○ Are large, ovoid, operculated,bile-stained and about
140µm by 80µm in size.
○ Contain an immature larva, the miracidium.
○ Do not float in saturated solution of common salt.
○ Eggs of F.hepatica and Fasciolopsis Buski cannot be
differentiated.
○ Eggs are unembryonated when freshly passed.

42. LIFE CYCLE

43. PATHOGENICITY
 Acute Or Invasive Phase
 Period during which the fluke migrates from the
intestine to the liver and its burrowing through the
liver parenchyma.
 No significant change from the intestine to the liver
 Parasite may wander or be carried by blood after
penetrating a blood vessel to ectopic sites such as
lungs, subcutaneous Tissues, brain and the orbit.
 Abscesses or fibrotic lesions Migration to the liver
parenchyma.
 Traumatic and necrotic lesions.

44.  Chronic Or Latent Phase
 period when the parasite has already reached the
bile ducts
 obstruction in the vessel
 inflammatory and adenomatous changes of the biliary
epithelium
 fibrosis of the ducts
 pressure atrophy of the liver parenchyma
 intensive periductal fibrosis
 Heavy infections
○ erosion of the epithelium
○ young worms wander back into the liver to produce
abscess pockets and to seed the vital liver tissue with
their eggs

45. DIAGNOSIS
 Clinical-based on:
○ Biliary symptoms.
○ Moderate to high eosinophilia.
○ Eating watercress as a green
salad(metacercaria in vegetation)
 Laboratory
○ Recovery of the eggs in the patient’s stool
or from duodenal or biliary tract drainage.
○ Serodiagnosis-helpful but not adapted
for routine diagnosis.

46. TREATMENT AND PROPHYLAXIS
 Oral triclabendazole(10mg/kg once) is the
treatment of choice.
 Alternative drug is bithionol(30-50mg for 10-
15days).
 Prednisolone at a dose of 10-20mg/kg is used
to control toxemia.
 PHROPHYLAXIS
 Health education.
 Control of snails.
 Proper disposal of human, sheep and cattle feces.
 Proper disinfection of watercresses and other water
vegetations before consumption.

47. DICROCOELIUM DENTRITICUM
Morphology
 slender, lancet shaped, flat transparent, aspinous body 5 to 15
mm by 1.5 to2.5 mm
 Acetabulum lies at the beginning of the second fifth of the
body
 two large, slightly lobed testes situated obliquely to each other
anterior to the small subglobose ovary just behind the ventral
sucker
 voluminous uterine coils in the posterior thirds of the worm
 Subglobose ovary lies to the right of the midline and
somewhat anterior to the equator of the worm
 discrete vitelline follicles occupy lateral fields in the middle of
the body.
 Eggs are deep golden-brown thick shelled, distinctly
operculated, measuring38 to 45u by 22 to 30u containing a
fully developed miracidium.

48. LIFE CYCLE

49. TREATMENT AND PROPHYLAXIS
 Praziquantel -25 mg per kg TID for 2
consecutive days
 PROPHYLAXIS:
 no effective measures of control
 Fresh herbs collected from grazing areas for use as
food for humans should be washed to remove the
ants.

50. CLONORCHIS SINENSIS
 COMMON NAME: Chinese liver fluke
 HABITAT: Biliary tract and sometimes
pancreatic duct.
 MORPHOLOGY:
 ADULT WORM:
○ 10-25mm long and 3-5mm broad.
○ Can survive for 15 years in biliary tract.
 EGGS:
○ Flask shaped, 35µm by 20µm with a yellowish
brown shell.

51. LIFE CYCLE

52. PATHOLOGY
 Distal bile ducts are irritated mechanically and by its
toxic secretions
 Slight leukocytosis and eosinophilia in early infection
 Enlarged tender liver
 Bile ducts thicken and become dilated and tortuous
 Adenomatous proliferation of the biliary epithelium
 Fibrosis and destruction of hepatic parenchyma
 Liver function is impaired although SGPT and SGOT
are normal

53. DIAGNOSIS
 CLINICAL DIAGNOSIS
 Suggestive in patients
from endemic areas with:
○ History of eating uncooked
fish.
○ Symptoms of biliarytract
disease
- intermittent jaundice
- bouts of fever
- right upper quadrant pain
 LABORATORY
DIAGNOSIS
 Finding the
characteristic eggs in
the feces or biliary
drainage or duodenal
aspiration.
 Eggs to be
differentiated from
opistorchid and
heterophyid flukes.

54. TREATMENT AND PROPHYLAXIS
 Praziquantel -25 mg per kg TID for 2
consecutive days
 PROPHYLAXIS:
 Proper cooking of fish.
 Proper disposal of feces.
 Control of snails.

55. OPISTHORCHIS SPECIES

56. INTESTINAL FLUKES

57. FASCIOLOPSIS BUSKI
 COMMON NAME: Giant intestinal fluke.
 First described by busk in 1843.
 HABITAT: Duodenum or jejunum of pigs and man.
 MORPHOLOGY:
 Largest fluke. Thick, fleshy, ovate.Flesh-coloured. 2-7.5
x 1-2 cm.
 Oral sucker and ventral suckers present.Typical
trematode alimentary canal with unbranched intestinal
caeca.
 Two dendritic testes.
 Single branched ovary.
 Vitellaria on lateral sides and a convoluted uterus and
genital pore that is anterior to theventral sucker.
 EGG: Yellowish and oval. 130-140 x 80-85 μ. Thin
walled with small operculum. Undeveloped ovum.

58. PATHOLOGY
 Attached to intestine by suckers.
 Mucosa inflamed, ulcerated and abscesses
form. Epigastric pain, nausea, diarrhoea.
 Heavy infection leads to oedema, ascites and
anarsaca.
 Toxic products of worm.
 Anaemia, leukocytosis, lymphocytosis, and
esinophilia.
 Good prognosis if worm treated early.
 1000-2000 worms affect intestinal secretions
and food passage and
 intoxication and sensitization.

59. LIFE CYCLE

60. DIAGNOSIS, TREATMENT AND
PROPHYLAXIS
 DIAGNOSIS:
 Eggs in feces. Differentiate from F. hepatica, Gastro discoides
and Echinostoma sp.
 Adult worms vomited or passed in stool.
 TREATMENT:
 Praziquantel(15 mg/kg) body weight, single dose is the drug of
choice .
 PROPHYLAXIS:
 Sanitary disposal of human feces.
 Discourage use of night soil.
 Restrict pigs.
 Snail control.
 Health education.
 Cooking or steeping of water plants.

61. HETEROPHYES HETEROPHYES
 MORPHOLOGY:
 Pyriform, greyish, 1.3 x 0.5 mm.Oral, Ventral and Genital suckers.
 EGG:
 Light brown in colour, thick shell, operculated, 29 x 16μm, Fully
developed miracidium.
 TREATMENT:
 Praziquantel(15 mg/kg) body weight, single dose is the drug of
choice .
 PROPHYLAXIS:
 Sanitary disposal of human feces.
 Discourage use of night soil.
 Restrict pigs.
 Snail control.
 Health education.
 Cooking or steeping of water plants.

62. METAGONIMUS YOKOGAWAI
 MORPHOLOGY:
 Small, 1.4 x 0.6 mm. Pyriform shape with rounded posterior
and tapering anterior. Large ventral sucker.
 EGG:
 Light yellow-brown, thin-shelled, operculated, 28x17 μm,
mature miracidium.
 TREATMENT:
 Praziquantel(15 mg/kg) body weight, single dose is the drug of
choice .
 PROPHYLAXIS:
 Sanitary disposal of human feces.
 Discourage use of night soil.
 Restrict pigs.
 Snail control.
 Health education.
 Cooking or steeping of water plants.

63. LUNG FLUKES

64. PARAGONIMUS WSTERMANI
 Common name: Oriental lung fluke
 History and Distribution:
 P. westermani was discovered in 1878 by
Kerbert in the lungs of Bengal tigers that died in
the zoological gardens at Hamberg and
Amsterdam.
 The parasite is endemic in the Far East—Japan,
Korea, Taiwan, China, and south east asia—Sri
Lanka and India. Cases have been reported
from Assam, Bengal, TamilNadu, and Kerala.
 P. mexicanus is an important human pathogen
in Central and South America.

65. MORPHOLOGY
ADULT WORM:
 The adult worm is egg-shaped about 10 mm long,
5 mm
 broad and 4 mm thick and reddish brown in color.
 The integument is covered with scale like spines.
 It has 2 unbranched intestinal caeca which end
blindly in the caudal area.
 They have a lifespan of up to 20 years in humans.
EGG:
 The eggs are operculated, golden brown in color and
about 100μm by 50μm in size.
 They are unembryonated when freshly laid.

66. LIFE CYCLE

67. CLINICAL FEATURES, DIAGNOSIS,
TREATMENT AND PROPHYLAXIS
 Clinical features:
 Peribronchial granuloma and cystic dilation of
bronchi. Dyspnea, hemoptysis, pneumonitis,
bronchiectasis, abcess, pneumothorax.
Extrapulmonary lesions in brain and intestine.
 Diagnosis:
 Ova in sputum, X-ray and CT scan of chest, CFT,
IHA, and ELISA.
 Treatment:
 Praziquantel is the drug of choice.
 Prophylaxis:
 Adequate cooking of crabs and crayfish, eradication
of molluscan hosts and treatment of infected
persons.

68. THANK YOU