1. بسم الله الرحمن الرحيم
TREMATODES

2. Remember
Autoinfection
Mode of infection
Infective stage
Definitive host
Intermediate host
Type of parasites
Source of infection
Vector
transmission

3. Trematodes (flukes)
Location in humans
Schistosoma hematobium
S. mansoni
S. japonicum
S. mekongi
s. intercalatum
Blood
Clonorchis sinensis
Dicrocoelium dendriticum
Opisthorchis felineus
O.Viverrini
Fasciola hepatica
f.gigantica
Liver
Fasciolopsis buski
Echinostoma spp
Heterophyes heterophyes
Intestine
Paragonimus westermani
lung

4. SCHITOSOMA

10. Egg with lateral spine Forked tail cercaria Diagnostic stage
Infective stage
Forked tail cercaria

12. Biomephlaria intermeddiat host

15. Schistosoma mansoni Is caused by persons passing faces
containing eggs of parasite into
water which is used for bathing
,washing clothes ,fishing ….
After mating ,mature S. mansoni
flukes migrate to small tributary
veins of inferior mesenteric, Which
drain large intestine. flukes can also
be found in portal venous system.

16. Life cycle
Person become infected by contact with water containing infective cercaria . Cercaria attached to skin and are able to penetrate unbroken skin (can penetrate mucous membranes).
During penetration cercaria loss their tail and develop into schistosomules which migrate through SC tissue into blood vessels.

17. In blood young flukes are carried through right side of heart to lung
From lung most of schistosomules pass through left side of heart ,enter abdominal aorta, and from there reach the portal (liver ) circulation.
In blood vessels of the liver ,young flukes reach maturity.

20. .
CLINICAL FEATURES :
Swimmer's itch: may occur at site of cercarial penetration.
In Schistosomiasis it is the eggs not adult which responsible for pathology.
Eggs acquiring host antigens and protected from attack by host immune responses.
Most eggs penetrate intestinal wall and excreted in stool with blood and mucus

21. Trapped egg mature normally secreting antigens that produce strong immune response.
Egg it self do not damage body,
cellular infiltration resultant from immune response that cause pathology associated with schistosomiasis

27. Eggs lodged in mucosa lead to formation of granuloma- ulceration and thickening of bowel
large granuloma lead to colonic and rectal polyp.
Eggs reach liver through portal vein causing thickening of portal vessels =periportal fibrosis –in heavy infection lead to enlarged liver with fibrosis-portal hypertension –ascites and splenomegaly.
Varicose v. in oesophagus –hematemesis
Eggs in spinal cord ,lung …..

34. pathology & clinical picture
of Schistosoma mansoni
1-per patent period.
2-egg deposition and
extrusion.
3-tissue proliferation.

35. 1-prepatent period: a-skin penetration: causing skin irritation
N.B. from cercarial skin
penetration to passage of eggs
(adult stage) it take 5-7 weeks.
b- systemic symptoms
(slight fever, muscle pain,--)

37. 2-Egg deposition and extrusion:
Affect mainly large intestinal wall,
liver and spleen.
Intestinal wall: schistosomal dysentery
(blood and mucus exudates in stool)
,thickening and fibrosis of colon and
rectum.
 Hepatomegaly: due to egg deposition.
 Splenomegaly: due to congestion
Egg deposition: in other organs e.g.
kidneys and spinal cord.

38. 3-Tissue proliferation & repair:
 Intestine:
fibrosis, thickening and development of papillomata, loss of tone , fibrous
constriction diarrhea fistulae.
 Periportal fibrosis ,esophageal varices
haematemesis ,ascitis.
 Pulmonary complications:
bronchopulmonary and cardiopulmonary (obstructive vascular disease ) cor pulmonale.
 CNS involvement.

41. Schistosoma hematobium

43. Pathology:
Swimmer's itch
Hematouria–eggs penetrate wall of
bladder (blood in urine).
Eggs trapped in wall of bladder causing
granuloma.
Many eggs calcified (sandy patch)
Urinary infection–kidney damage –
squamous cell carcinoma.
Stones , nephrotic syndrome.

48. pathology& clinical picture
of Schistosoma hematobium
1. Pre-patent period.
2. egg deposition and extrusion.
3. tissue proliferation.

49. 1-Prepatent period cause skin irritation N.B. From cercarial
a.Skin penetrations :
cause skin irritation
N.B. From cercarial
penetration to passage of
eggs (adult stage) it take 10-
12 weeks.
b.Systemic symptoms
(slight fever, muscle pain…)

51. 2-Egg deposition and extrusion
Most eggs traped in sucbmucosa and
muscularis of bladder.
Initially painless terminal haematuria
for months to years, then burning
micturition.
 Cystoscopy shows hyperplasia and
inflammation of lower bladder, initial
papillomata.

53. 3- Tissue proliferation& repair:
a- Generalized hyperplasia and
fibrosis of bladder, lower ureter,
sandy patches, squamous cell
carcinoma.
b- Calaculi: obstructive uropathy
leading to:
-retrograde infection.
-hydronephrosis and renal failure.

55. portal vein …liver (PPF) d- lung involvement (eggs from
c- periportal fibrosis (eggs from
v. of rectum and colon…
portal vein …liver (PPF)
d- lung involvement (eggs from
hypogastric vein to- common
iliac vein to –heart to lung )

57. Diagnosis of schistosomiasis:
Is by finding eggs depending on species in urine ,feces, or rectal scraping.

58. Parasitological diagnosis : Urinary schistosomiasis
urine : sedmentation, centrifugation,and filtration
Aspirate : bladder cystoscopy.
Biopsy : rectum protoscopy

59. Intestinal schistosomiasis:
Stool examination
Direct smear
Thick smear (kato method)
Concentration methods.
Rectal mucosa :
swab, aspirate and biopsy.

60. schistosomiasis: Ancillary investigation in Endoscopy: papillomta
Radiological
- Ultrasound for liver periportal fibrosis.
- X-ray
calcification ,obstructive uropathy
Pulmonary changes e.g. cor pulmonale
Serological tests:
ELISA mainly survey method to detect:
Ab :light or old infection
Ag :in active infection.

62. Chemotherapy of schistosomiasis
praziquantel.

63. FASCIOLA HEPATICA

66. Fasciola hepatica Large fluke, 3x1.5cm Causing fascioliasis
Common parasites of herbivores,
cosmopolitan, mostly in sheep
raising areas.

67. Immature egg

68. _Fasciola-hepatica-Egg

73. Life cycle of
Fasciola heptica

74. Life cycle Adult egg (in water) miracidium
(pierce snail soft tissue multiply
give sporocyst rediacercaria
metacercaria
(infective stage on water plant),
Upon ingestion
metacercaria burrows through
duodenal wall liver parenchyma
bile duct where it becomes adult.

75. Pathology Invasion of adult to biliary tree
producing biliary obstruction and
fibrosis.
Eating raw liver infected with
Faciola, adult worm attaches to
pharyngeal mucosa causing pain,
bleeding and edema.

76. Diagnosis Treatment : Control: Eggs in duodenal aspirate and stools.
(Exclude spurious infection.)
Treatment :
Bithionol
Control:
Avoid ingestion of infected plants.

77. الحمد لله