Introduction to tromatodes

1
Introduction to tromatodes

• Phylum PlatyhelminthesClass TrematodaOrder
  Digenea

2
Morphology

• Adult worm
• Flattened (flatworm) and leaf like
• Sucker oral ventral (fluke)
• Body wall musculo-tegumental sac
• Parenchyma (structure between body wall and
  internal organs) connective tissue fibers, cells
  and space between them

3
(No Transcript)
4

• Digestive tract not intact i.e. no anal
  opening, caecum
• Reproductive system hermaphrodite (monoecious)
  exception of schistosome
• Muscular system
• Nervous system
• Excretory system

5

• Egg
• Size divergent
• Ovoid
• Operculum (exception of that of schistosome)
• Content ovum , vitelline cells, or miracidium

6
Egg of Clonorchis sinensis
7
Egg of Paragonimus westermani
8
Egg of Fasciolopsis buski
9
S. japonicum S. Mansoni S.
haematobium Schistosome egg
10
Features Reflecting Adaptation to Parasitism

• Organs of attachment highly developed
• Retardation of digestive system
• Highly developed reproductive system

11
Life Cycle

• Complex
• Alteration of generationsexual generation and
  asexual generation alter in the life cycle of
  parasite
• Asexual multiplication in larval stage in snail
  host
• Multiple hosts transfer and having reservoir
  hosts in majority
• Water environment is essential

12
Important Species

• Liver fluke Clonorchis sinensis
• Intestinal fluke Fasciolopsis buski
• Lung fluke Paragonimous westermani
  P. skrjabini
• Blood fluke Schistosoma spp.

13
The Liver Fluke???Clonorchis sinensis??????
14
Introduction

• Parasite of biliary passage
• Cause clonorchiasis
• A common trematode in Far East
• First report 1874 oversea Chinese in India

15
Morphology

• Adult worm
• Size Shapelike the seed of sunflower
• Sucker oral ventral
• 2 dendritic testes lie in tandem to each other in
  the posterior region (clonorchis)

16
Adults of Clonorchis sinensis
17
(No Transcript)
18
(No Transcript)
19
Cross section of Clonorchis sinensis adult in the
hepatic bile duct
20

• Egg
• Size smallest
• Shape just like sesame
• Color yellowish brown
• Operculum distinct shoulder, knob
• Content miracidium

21
Clonorchis sinensis egg.  These are small
operculated eggs.  Size 27 to 35 µm by 11 to 20
µm.  The operculum, at the smaller end of the
egg,  is convex and rests on a visible
"shoulder".  At the opposite (larger,
abopercular) end, a small knob or hooklike
protrusion is often visible (as is the case
here).  The miracidium is visible inside the egg.
22
Egg of Clonorchis sinensis
23
Life cycle of Clonorchis sinensis
24
Life Cycle

• A model pattern of trematode
• Main points
• Definitive host human being
• Reservoir host dog, cat, etc.
• Residing hepatic bile duct
• Discharge of eggs with feces

25

• Hatching in the host small intestine
• 2 intermediate hostI snails, such as
  Bithynia,ParafossarulusII freshwater fishes,
  such as Cyprinus
• 2 generation of asexual proliferation
• Infective stage metacercaria in fish
• Infective route oral consumption

26
Pathogenesis

• Due to adult worm
• Mechanism
• Mechanical sucker
• Chemical excretions, secretions, metabolite
• Biological nutrition deprivation

27

• Pathological process
• Inflammation ?Proliferation?Thickening?Occlusion
• Extensive involvement?Fibrosis of the liver

28
Clinical Manifestations

• Acute stage allergic reaction
• Chronic stage functional impairment of liver
  (Cholangitis, Cholecystitis, Bile stone,
  Jaundice, etc)
• Advanced stage portal cirrhosis
  malignancy

29
Laboratory Diagnosis

• Etiological
• Examination of egg in feces by sedimentation
  method
• Duodenal aspiration
• Immunological
• ELISA to detect antiboby or antigen

30
Epidemiology

• Distribution
• Far East(China, South Korea, Japan, etc.)
• 24 provinces in China(Guangdon 5 million
  infected etc.)

31
(No Transcript)
32
Endemic Factors

• Source of infection mainly wild carnivores
• I,II intermediate host in the same water-field
• Mode of fish breeding
• Dinning habit Customs

33
Principle of Control

• Cure patients carrier
• praziquantel25mg/kg, tid, 2 days
• Control reservoir host
• Carry out scientific fish-breeding
• Hygienic educationnot eating raw or undercooked
  fishes

34
Paragonimus westermani?????? Paragonimus
skrjabini(Paragonimus szechuanensis)??????
35
The Lung Fluke

• Genus paragonimus
• Zoonotic parasite (cause zoonosis)
• Animal infectiongt human infection
• 2 major species in China

36
Introduction

• Pathogen of lung disease
• Endemic hemoptysis
• Favorite lodging site lung
• Ectopic site brain, abdomen, muscle, etc.

37
Morphology

• Adult worm
• Body thick (a half piece of a bean grain)
• Tegument spinous
• Sucker oral ventral
• Parallel arrangement of reproductive
  organlobular testes (posterior)lobular ovary
  uterus (anterior)

38
(No Transcript)
39
Cross section of lung containing adult
Paragonimus westermani.
40

• Egg
• Median size, ovoid (water pot)
• Golden yellow
• Distinctive wide operculum
• Contain 1 germ cell several yolk cells

41
Egg of Paragonimus westermani.
42
Crab or crayfish
Life cycle of Paragonimus westermani.
43
Life cycle

• Definitive host human being
• Reservoir host carnivorous animals
• Habitation lung ectopic site
• Intermediate hostI Melania snailsII stream
  crabs, crayfish

44

• Infective stage metacercaria
• Infective mode oral route, may via paratenic
  host (swine)
• Migration Preadult wondering
• Ectopic parasitism cerebral, abdominal,etc.
• Eggs discharged with sputum feces
• 3 generation of asexual multiplication

45
(No Transcript)
46
Pathogenesis

• Stage take responsibility adult preadult
• Pathological processes
• Abscess stage(???)
• Cystic stage(???)
• Scar formation stage(?????)

47

• 4 clinical types
• Thoracic (pulmonary type)chest pain, coughing,
  blood-tinged sputum(hemoptysis)
• Abdominal (hepatic type)hepatomegaly
• Cranial type dizzy, headache, epilepsy
• Musculocutaneous type migratable subskin nodule

48
Laboratory diagnosis

• Disease history physical examination
• Etiological diagnosiseggs in sputum or feces by
  sedimentation
• Immunological diagnosisfor ectopic infections

49
Epidemiology

• Globalmain continent except Europe
• China 23 provinces

50
Paragonimus westermani infection occurs in Asia
(especially in China (Taiwan), Corea, India,
Japan, Laos, Philippines, Sri Lanka, Thailand,
Viet-Nam), Central-West Africa, South America
(Ecuador, Peru Venezuela).
51
Principle of control

• Treat patient praziquantel
• Hygienic education
• Social construction, economic refinement

52
The Ginger Fluke???Fasciolopsis
buski??????Intestinal fluke????
53
Morphology

• Adult worm
• Like a ginger piece
• Big muscular trematode
• Have strong suckers,ventral gtgt oral

54
Adult fluke of Fasciolopsis buski The adult
flukes range in size 20 to 75 mm by 8 to 20 mm
55
Fasciolopsis buskii adult worm
56

• Egg
• Biggest
• Ovoid
• Minute operculum
• Yellowish
• Germ cell inclusions

57
F.buski eggs are released in feces unembryonated.
The operculated eggs are oval, brown and measure
130-150 by 78-100 um
58
Life cycle of Fascilopsis buski
59
(No Transcript)
60
Life Cycle

• Definitive host human being
• Reservoir host swine, etc.
• Intermediate host Planorbis snails
• Aquatic plant vectors caltrops, water chestnut,
  etc.
• Habitation small intestine

61

• Infective stage metacercaria
• Infective route oral
• Developmental stages as Paragonimus
• 3 generation of asexual proliferation

62
Pathogenesis Factors

• Traumatic (suckers)
• Obstructive (due large size)
• Toxic (excretion, secretion, metabolite)

63
Clinical Manifestation

• Abdominal pain
• Acute intestinal obstruction
• Anemia
• Generalized edema

64
Laboratory Diagnosis

• Examination of egg in feces by sedimentation
  method

65
Epidemiology

• Aquatic plant raising districts

66
Fasciolopsis buski is endemic in China (Taiwan),
South-East Asia, Malaysia and India.
67
Principle of Control

• Drug for treatment praziquantel
• Water nightsoil control Scientific swine
  raising
• Hygienic education

68
Introduction

• 6 species of human schistosomes
• Schistosoma japonicum
• S. mansoni
• S. haematobium
• S. intercalatum
• S. mekongi
• S. malayi

69
Schistosoma japonicum

• ?????

70
Distribution and Epidemic Situation

• Worldwide
• 200 million of population infected in 74
  countries(S.m. 55 S.h. 55 S.j. 4 S.i.
  10 S.me. 2 S.ma. 1)
• China
• 11 million in 12 provinces ? 0.7 million in 8
  provinces

50 years
71
Before control After
control (1996) Regional distribution of S.
japonicum infection in China
72
Morphology

• Difference from other trematodes
• Dioecious adults
• Non-opeculate egg
• Bifurcated (forked) cercaria invades the final
  host by skin
• Adults parasitize blood vessels

73

• Adult
• Male (15 mm length) lt female (22 mm)
• Oral sucker lt ventral sucker
• 2 paralleled guts form a blind caecum in the
  posterior ends
• 7 testes in male and single ovary with a tubule
  uterus in female
• Gynecophoric canal (male) in which female repose

74
(No Transcript)
75


76
(No Transcript)
77

• Egg
• Ovoid and non-opeculate
• 74106 ?m 5580 ?m
• Contains one miracidium
• Bear a minute lateral knob.
• Miracidium
• Cercaria

78
S. japonicum S. Mansoni S.
haematobium Schistosome egg
79
Schistosome miracidium
80



Schistosome cercaria
81
Life Cycle
Eggs discharged ? fresh water (hatch) ? miracidia
? penetrate oncomelania(I.H.)?mother sporocysts
(multiplication) ? daughter sporocysts
(multiplication) ? cercariae (infective form) ?
skin penetration of D.H. ? schistosomulum ? right
heart ? lungs ? left heart ?systemic circulation
? portal system ? pairing and sexual maturation
? mesenteric veins ?lay eggs ?eggs develop and
live in tissue for 21 days( 23 in liver tissue,
60 in intestinal tissue, 17 discharged)
82
(No Transcript)
83
Cercarial dermatisis due to avian schistosome
84
Main Points of Life Cycle

• Residing site mesenteric vein
• I.H.(Only one) Oncomelania hupensis
• No metacercaria and redia stage
• Two generation of sporocyst
• Infective stage cercaria
• Route of infection skin penetration

85



Adult of Schistosome in mesenteric veins of
hamster

86



Onchomelania hupensis
87

• Skin penetration of cercaria ? first appearance
  of eggs 3035 days
• Life spans in human 45 years, longest 35 years

88

• Tissue egg
• The egg which can develop and live in tissue
• Significance of tissue egg
• Major pathogenic stage, inflammation and
  granuloma around the egg
• Diagnosis and evaluation of therapeutic efficacy

89
Immunity

• Concomitant immunity
• Host carrying an initial infection of adult
  schistosomes shows the protection to a cercarial
  challenge infection (?????)and this protective
  immunity will disappear with eradication of
  schistosomes in the host

90

• Immuno-evasion Its an ability by which the
  schistosome adult can evade the host immune
  response. The possible mechanism of evasion.
• Acquire host antigen on it surface
• Host-like antigen produced by parasite
• Changing of tegument very quickly
• Parasite may inactivate or down-regulate immune
  effectors

91
Pathogenesis

• Schistosomiasis at each stage of the life cycle
  in human body
• Cercaria (skin-penetration)
• Dermatitis
• Schistosomula (migration)
• Larva migrans
• Adult (immunocomplex)
• Immuno-nephropathy

92

• Tissue egg principal pathogenic stage

• Miracidium within egg?SEA?Sensitization of T Cell
  
• Th1?IL-2, INF-?, TNF ? activate macrophage,
  induce? cell-mediated immunity
• Th2?IL-4, IL-5? stimulate IgE production or
  eosinophilia
• inflammation and granuloma ? fibrosis? portal
  hypertension
  ?
  intestinal polyp

93
Clinical Form

• Acute schistosomiasis
• Fever, diarrhea, abdominal pain, enlargement of
  liver or spleen
• Chronic schistosomiasis
• asymptomatic or diarrhea, abdominal pain,
  enlargement of liver or spleen
• Advanced schistosomiasis
• Ascites splenomegalycollateral circulation
  dwarfism
• Ectopic lesion encephalitis focal epilepsy

94




Advanced schistosomiasis patient with portal
hypertension and ascites
95
A patient with S. j has marked ascites,
splenomegaly,umbilical hernia and distended
superficial abdominal veins.
96
Diagnosis

• Parasitological diagnosis (etiological,
  definitive diagnosis)
• Demonstrating eggs by stool examination
• Stool examination after concentration
  (sedimentation)
• Miracidium-hatching from eggs
• Rectal biopsy eggs-demonstration

97
Miracidium-hatching from eggs

• Necessity tissue ova
• low egg burden due to mass treatment
• Possibility
• Hatch quickly (T25 limpid water free of
  Cl2light pH6.8-7.8)
• Three tropismlimpidity, phototrophic, ascendancy
• Swimming in a zigzag way

98

• Immunodiagnosis (indirect diagnosis)
• Detection of antibodies in serum, urine, saliva
  by ELISA, but is impossible to distinguish
  current infection from past infection.
• Detection of antigens (circulation anodic and
  cathodic antigen)

99

• Combined diagnosis including epidemiological
  antecedent, symptoms and signs, parasitological
  and immunological examination.

100
Treatment

• Praziquantel 60 mg/kg divided in 3 doses.

101
Factors of Transmission and Prevention

• Factors
• Source of infection patients and reservoir host
• Intermediate host Oncomelania
• Contact with cercaria-infected water

102

• Preventive measures
• Detection and treatment of patients and reservoir
  host
• Elimination or control of oncomelania
• Protection of susceptible population and
  avoidance of contact with cercaria-infected water
• Prevention of water contamination by human night
  soil

103
Distinguishing of 3 major schistosomes

• (see page 54, Table 3-1)

104
(No Transcript)