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Schistosoma Parasites Adult Flukes live in blood vessels of infected Humans S.haematobiumS.mansoniS.japonicum Called Blood Flukes D.H: Man R.H: Rodent,

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Presentation on theme: "Schistosoma Parasites Adult Flukes live in blood vessels of infected Humans S.haematobiumS.mansoniS.japonicum Called Blood Flukes D.H: Man R.H: Rodent,"— Presentation transcript:

1 Schistosoma Parasites Adult Flukes live in blood vessels of infected Humans S.haematobiumS.mansoniS.japonicum Called Blood Flukes D.H: Man R.H: Rodent, Monkeys D.H: Man R.H: Domestic animals D.H: Man R.H: None RAAFAT T. MOHAMED

2 Definitive Host Man Habitat Superior & Inferior mesenteric plexus of veins Vesical & pelvic plexus of veins Where adult S.mansoni live Where adult S.haematobium live Blood vessels Inferior mesenteric plexus of veins Where adult S.japonicum live RAAFAT T. MOHAMED

3 Has separate sexes. Lives in blood. Has non-operculated eggs. Has no Redia stage. Has no encysted metacercaria. Common species affecting man: S. mansoni, S. haematobium, S. japonicum, S. intercalatum and S. mekongi. Schistosoma differs from other trematodes in: RAAFAT T. MOHAMED

4 Theodore Bilharz: discovered the worms and their relation to the disease in 1851 in Cairo. Manson: (1893): Discovered that there are 2 different species of the parasite in Egypt. Leiper (1915- 1918): Discovered the relation to snail intermediate hosts and the mode of infection. McDonagh (1918) Used tartar emetic for treatment Recent discovery: RAAFAT T. MOHAMED

5 Sexes: separate Female: cylindrical Male: flattened, folded (gynaecophoric canal). Suckers: oral & ventral (smaller in females). Digestive system: No muscular Pharynx Intestinal ceaca reunite in a single caecum. Adult Morphology RAAFAT T. MOHAMED

6 S. haematobium S. mansoni S. japonicum 10x 1 mm 8x1 mm 15xo.5 mm 3-5 testes in a line 6-9 testes in cluster 6-8 testes in a line Fine tubercles course tubercles No tubercles Male RAAFAT T. MOHAMED

7 Female S. haematobium S. mansoniS. japonicum 20x0.2 mm14x0.15 mm26x0.3 mm Ovary post 1/3ovary ant. 1/3Ovary in the middle Vit. gl. post 1/3vit. gl post 2/3Vit. gl. in post 1/2 RAAFAT T. MOHAMED

8 Egg S. haematobiumS. mansoniS. japonicum In urineIn stool Size140x 60 150x60 85x65 ShapeOval terminal spine Oval Lateral spine Ovoid Minute knob Shell translucent, non operculated Content Mature embryo (miracidium) RAAFAT T. MOHAMED

9 Miracidium S. mansoni Biomphalaria alexandrina Snail I. H S. Haematobium Bulinus truncatus S. japonicum Oncomelania RAAFAT T. MOHAMED

10 Infective stage (Cercaria): Formed of body and forked tail (furcocercous) 5-6 pairs of penetration glands. Skin penetration is aided by: 1-Proteolytic enzymes. 2-Surface tension of drying water. 3-Movement of the tail RAAFAT T. MOHAMED

11 Worms in their habitat Female lays eggs Eggs in urine or stools Miracidia hatch Miracidium infects snail i.h. Cercarial shedding Infection in contaminated water Schistosomulum reaches circulation Worms mate in the liver RAAFAT T. MOHAMED

12 Life cycle RAAFAT T. MOHAMED

13 Development of Schistosoma inside the body of infected human Cercariae penetrates human skin Schistosomula Venous circulation Systemic circulation Liver Portal vein Vesical plexus I III IV II Inf. mesenteric plexus Aorta In urine or stoolDirection of venous blood flow S.haematobium S.mansoni RAAFAT T. MOHAMED

14 Pathogenesis and Clinical Picture There are 4 progressive stages: I- Stage of invasion Local dermatitis, irritation. Papular rash. (1-4 days) RAAFAT T. MOHAMED

15 II- Stage of migration By schistosomula (3-4 weeks) Metabolic products: toxic and allergic manifestations as urticaria, fever, headache, muscle pain. In the lung: verminous pneumonitis, minute haemorrhage cough, haemoptysis. In the liver: enlarged and tender. RAAFAT T. MOHAMED

16 III- Stage of egg deposition and extrusion The patient may complain of: Generalized malaise, fever, rigors, urticaria, abdominal pain and liver tenderness. A- Eggs are deposited in the venous plexus Urticaria (acute stage: 1-2 month) RAAFAT T. MOHAMED

17 Katayama Syndrome Blood vessel Soluble egg antigens are released in blood stream Occurs mainly in S.japonicum infection 1- lays large number of eggs 2- greater proximity to the liver immune complex Deposited in the tissues Tissue damage The patient suffers from: Fever, chills, diarrhoea, generalized lymphadenopathy Due to: Thus also called acute toxoemic schistosomiasis antibodies Circulate RAAFAT T. MOHAMED

18 B- Stage of egg extrusion: Terminal haematuria, frequency of micturition, burning pain Dysentery with blood and mucus in stool In vesical & pelvic plexus of veins Bladder wall In mesenteric plexus of veins Intestinal wall Damage & haemorrhage S.haematobiumS.mansoni & S.japonicum Eggs escape from the veins to the perivascular tissue due to: 1-Pressure within the venule 2-Effect of the spine 3-oozing lytic secretion of the miracidium within the egg Egg extruded RAAFAT T. MOHAMED

19 IV- Stage of tissue reaction (chronic stage) Occurs around Schistosoma eggs deposited in various tissues. Attract inflammatory cells Deposition of fibrous tissue Damage of affected organ and its fibrosis Loss of its function Egg shell miracidium Inflammatory cells Shell & miracidial antigens Delayed-type hypersensitivity Granuloma formation in tissue (months – years) Granuloma develops RAAFAT T. MOHAMED

20 Polyps in the colon in S.mansoni infection hydroureter hydronephrosis Egg trapped in bladder wall Fibrous tissue Stone formation In normal condition In S.haematobium infection Cancer bladder may occur Normal mucosa of colon RAAFAT T. MOHAMED

21 IV- Stage of tissue reaction (chronic stage) In S.haematobium infectionIn S.mansoni infection Eggs extruded in urine 1 Eggs trapped in Bladder wall 2 Eggs fail to fix to venule wall are swept by blood 3 Eggs trapped in Intestinal wall Eggs extruded in stool 1 2 Eggs fail to fix to venule wall are swept by blood 3 Cause Embolic lesions RAAFAT T. MOHAMED

22 Embolic Lesions in the Liver Portal hypertension Hepatosplenomegaly Oesophageal varices Ascites. RAAFAT T. MOHAMED

23 Embolic Lesions in the lung Pulmonary hypertensionBilharzial cor-pulmonale Embolic lesions may occur in any other organ. Cor-pulmonale = right-sided heart failure Dilated right ventricle Thickened wall In Normal condition In Schistosoma infection Enlarged right ventricle Trapped eggs Means: enlargement of right ventricle due to high blood pressure in the arteries of the lung RAAFAT T. MOHAMED

24 Diagnosis of Schistosomiasis Clinically (suggestive) Laboratory 1- Detection of eggs in urine or stool 3- Serological tests 2- Blood examination Radiological imaging Endoscopy 1- History of contact with infected water. 2- Clinical picture according to stage of infection. RAAFAT T. MOHAMED

25 I- Laboratory Diagnosis 1- Direct parasitological methods: - Detection of S.haematobium eggs in urine. - Test for viability. - Detection of S.mansoni eggs in stool by direct smear method or by concentration method. - Kato thick faecal smear: for egg counting to assess the intensity of infection - Rectal swab S: 140X60 µ150X60 µ Oval, thin shell Terminal spineLateral spine S: C:Translucent C:Miracidium RAAFAT T. MOHAMED

26 I- Laboratory Diagnosis Eosinophilia, leucocytosis. 2- Blood examination: 3- Serological Tests: Detection of anti-Schistosoma antibodies or antigen in patients serum a- IHAT (Indirect Haemagglutination test) Latex particles Sensitized sheep RBCs +ve -ve (Immunodiagnostic Tests) Anaemia due to 1- Egg extrusion Iron deficiency anaemia 2- Hypersplenism Haemolytic anaemia RAAFAT T. MOHAMED

27 b- ELISA (Enzyme-linked immunosorbent assay) c- IFAT (Indirect Fluorescent Antibody test) wash Ab detected wash Ag detected Coating with Schisto Ag Coating with anti-Schisto MAb Schisto Ag Patient serum Ab detected Patients serum Ab linked to enzyme substrate Patients serum Ab linked to enzyme RAAFAT T. MOHAMED

28 Calcified bladder with hydroureter Intestinal affection Stenosed ureters and hydronephrosis II- Radiological imaging S.haematobium infectionS.mansoni infection RAAFAT T. MOHAMED

29 المناظير III- Endoscopy Cystoscopy in S.haematobium Colonoscopy, sigmoidoscopy in S.mansoni Done in chronic cases to detect lesions and take biopsies RAAFAT T. MOHAMED


31 Treatment RAAFAT T. MOHAMED Praziquantel (Biltricide): For all schistosome species. Dose:40 mg/kg single oral dose Oxamniquine (vancil): For S. mansoni Dose: 30 mg/kg for 2 days Metriphonate: For S. haematobium only. Dose: 10mg/kg every 2 weeks for 3 doses.

32 RAAFAT T. MOHAMED Prevention and Control - Mass treatment. - Health Education. - Snail control: Physical methods Biological methods Chemical methods X Balanites aegyptica Copper sulphate

33 Cercarial Dermatitis (Bathers itch) A condition that occurs due to penetration of cercariae of non-human species of schistosomes the skin of man. Cercariae cannot go beyond the germinal layer. Clinical picture: Dermatitis, itching, oedema and secondary bacterial infection. Treatment: Antipruritics, antihistamincs, antibiotics. RAAFAT T. MOHAMED

34 b- S.japonicum b- Schistosomiasis mansoni d- Fascioliasis b- S.mansoni d- non human schistosomes Multiple Choice Questions The major cause of morbidity in schistosomiasis is: a- Migration of adult worms against blood stream. b- Maturation of worms to adult stage in the liver. c- Occurrence of Embolic lesions. d- Deposition of eggs in tissues. Kato technique is used to diagnose: a- Paragonimiasis c- Schistosomiasis haematobium Bathers itch occurs frequently with: a- S.haematobium RAAFAT T. MOHAMED

35 Katayama syndrome: a- occurs most frequently in S.haematobium infection. b- occurs most frequently in S.mansoni infection. c- occurs most frequently in S.japonicum infection. d- occurs in chronic schistosomiasis. Multiple Choice Questions RAAFAT T. MOHAMED

36 Give reasons for Terminal haematuria is due to active deposition of eggs by adult female S. haematobium in vesical venous plexuses. Eggs escape to the perivascular tissue and become extruded to the lumen of the urinary bladder. Powerful contraction of the bladder at the end of micturition (to squeeze the last drops of urine) leads to haemorrhage (terminal haematuria). Occurrence of terminal haematuria in S.haematobium infection Egg passes lumen of urinary bladder RAAFAT T. MOHAMED

37 Give reasons for Many eggs that fail to be fixed to walls of venules are swept by blood to reach various organs as the lungs where they form granulomas and fibrosis with obliteration of flow resulting in pulmonary hypertension and right- sided heart failure. Occurrence of Bilharzial cor-pulmonale in schistosomiasis Swept by blood LungHeart RAAFAT T. MOHAMED

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