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Schistosoma

Schistosoma. General character : Morphology Reproduction system Importance. Morphology. Size : - Female 12 to 26 mm - Male 6 to 22 mm. The three main species infecting humans are Schistosoma haematobium , S. japonicum , and S. mansoni . 

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Schistosoma

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  1. Schistosoma • General character: • Morphology • Reproduction system • Importance

  2. Morphology • Size: - Female 12 to 26 mm - Male 6 to 22 mm The three main species infecting humans are Schistosoma haematobium, S. japonicum , andS. mansoni.  Two other species, more localized geographically, areS. mekongiandS. intercalatum

  3. Adult an larve of Sch. Schistosomulum

  4. Geographic Distribution • Schistosoma mansoniis found in parts of South America and the Caribbean, Africa, and the Middle East; • S. haematobiumin Africa and the Middle East; and • S. japonicumin the Far East. • Schistosoma mekongiandS. intercalatumare found focally in Southeast Asia and central West Africa, respectively.

  5. Life Cycle

  6. Miracidium & Cercaria

  7. Liver worm

  8. Clinical Features • Many infections are asymptomatic.  • Swimmer’s itch ( Cercarial Dermatitis) • Acute schistosomiasis (Katayama's fever) may occur weeks after the initial infection, especially byS. mansoniandS. japonicum. • .  Manifestations include fever, cough, abdominal pain, diarrhea, hepatospenomegaly, and eosinophilia. •   Occasionally central nervous system lesions occur: • cerebral granulomatous disease may be caused by ectopicS. japonicumeggs in the brain, and granulomatous lesions around ectopic eggs in the spinal cord fromS. mansoniandS. haematobiuminfections.

  9. Schistosoma egg • JK Sch.mansoni egg Sch. japonicum egg Sch. Haematobium egg

  10. Epidemiology of Schistomiasis

  11. Intermediate host

  12. Cercarial Dermatitis

  13. Immuno-pathologic consequences • Continuing infection may cause granulomatous reactions and fibrosis in the affected organs, which may result in manifestations that include: • colonic polyposis with bloody diarrhea(Schistosoma mansonimostly); • portal hypertension with hematemesis and splenomegaly(S. mansoni, S. japonicum,) • cystitis and ureteritis(S. haematobium)with hematuria, which can progress to bladder cancer; • pulmonary hypertension(S. mansoni, S. japonicum, more rarelyS. haematobium); glomerulonephritis; and central nervous system lesions

  14. Hepatomegaly & splenomegaly

  15. Granuloma( Sch. japonicum egg)

  16. Granuloma( Sch. hematobium egg)

  17. Granuloma

  18. Laboratory Diagnosis • Microscopic identification of eggs in stool or urine is the most practical method for diagnosis. • Stool examination should be performed when infection withS. mansoniorS. japonicumis suspected, • and urine examination should be performed ifS. haematobiumis suspected. Tissue biopsy (rectal biopsy for all species and biopsy of the bladder forS. haematobium) may demonstrate eggs when stool or urine examinations are negative.

  19. Antibody detection • Antibody detection can be useful to indicate schistosome infection in patients who have traveled in schistosomiasis endemic areas and in whom eggs cannot be demonstrated in fecal or urine specimens.

  20. Treatment • Safe and effective drugs are available for the treatment of schistosomiasis.  • The drug of choice is praziquantel for infections caused by allSchistosomaspecies.  • Oxamniquine has been effective in treating infections caused byS. mansoniin some areas in which praziquantel is less effective. 

  21. شاداب و سر حال باشيد

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