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TREMATODES

TREMATODES. PM2 Pathophysiology. Trematodes. multicellular eukaryotic helminths unsegmented leaf-shaped worms MONECIOUS except for schistosomes (DIECIOUS). TREMATODES. blood flukes Schistosoma mansoni S. japonicum S. hematobium . intestinal fluke Fasciolopsis buski

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TREMATODES

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  1. TREMATODES PM2 Pathophysiology

  2. Trematodes • multicellular eukaryotic helminths • unsegmented leaf-shaped worms • MONECIOUS except for schistosomes (DIECIOUS)

  3. TREMATODES • blood flukes Schistosoma mansoni S. japonicum S. hematobium. • intestinal fluke Fasciolopsis buski • liver fluke Clonorchis sinensis • lung fluke Paragonimus westermani.

  4. Trematodes • MOT: 1. cercariae - FREE SWIMMING LARVAE - given off by infected snail - penetrate the skin of the human definitive host 2. metacercariae - encysted form of the cercariae - edible plants or animals water plants fishs crustaceans

  5. Praziquantel -paralysis of musculature -attachment of phagocytes to parasite and death.

  6. Schistosomiasis (Bilharziasis) • S. hematobium: Africa • S. mansoni : Africa and America • S. japonicum: Far East. • 250 million people are infected

  7. Morphology • Adult worms are 10 to 20 mm long • Male: lamelliform shape with marginal folds

  8. “The sweetest parasites on earth”

  9. SCHISTOSOMESMOT: skin penetration by cercariae

  10. FAVORITE SITES • S. japonicum :VEINS OF GIT • S. mansoni : VEINS OF GIT • S. haematobium : VEINS OF BLADDER

  11. Schistosomiasis • type I and type IV hypersensitivity • collagenase: damage to the vascular endothelium.

  12. Three major disease syndromes occur in schistosomiasis • 1. schistosome dermatitis • 2. acute schistosomias (Katayama fever) • 3. chronic schistosomiasis.

  13. dermatitis (swimmers' itch): penetration of cercariae

  14. Acute schistosomiasis(Katayama fever) -4 to 8 weeks after primary exposure -cough, hepatosplenomegaly -lymphadenopathy,and eosinophilia

  15. Chronic disease • may appear many years later • japonica and mansoni hepatomegaly splenomegaly portal hypertension esophageal varices

  16. schistosomiasis haematobium inflammation and fibrosis obstruction hydronephrosis uremia

  17. Schistosoma eggs in the intestinal mucosa

  18. S. Haematobium and bladder cancer

  19. Schistosomiasis

  20. Characteristic eggs: diagnosis Apical spine: S. haematobium Lateral spine: S. mansoni Vestigial spine: S. japonicum

  21. Treatment and control • Praziquantel is effective against all species. • Contaminated water should be avoided. • Control measures include sanitary disposal of sewage and destruction of snails. • No vaccine is available.

  22. Fasciolopsis buski (Giant intestinal fluke) • central and southeast Asia. • elongate oval fluke • 2 to 7 cm long • small intestine

  23. Fasciolopsis buski:MOT: INGESTION OF CYSTS

  24. Pathology • attaches itself to the intestinal mucosa • inflammation, ulceration, abscesses

  25. WATERCRESS

  26. Fasciolopsiasis • DiagnosisEggs in feces • Treatment and controlPraziquantel • Water chestnuts • Sewage treatment

  27. Clonorchis sinensis(Chinese Liver Fluke) • parasite of man, dogs and cats in the southeast of Asia • extraordinarily common: China, Korea and Japan

  28. Clonorchiasis • Morphology • spindloid flukes

  29. MOT: INGESTION OF METACERCARIAE

  30. Clonochis adult worms in the liver

  31. CLONORCHIASIS • irritation of the bile ducts  dilated • Liver: enlarged necrotic tender elevated liver enzymes

  32. CLONORCHIASIS • Diagnosiseggs in the feces or bile • Treatment and controlPraziquantel • Fish should be cooked well before consumption. • Sewage must be treated before disposal.

  33. Paragonimus westermani (Lung Fluke) • most commonly encountered in parts of Asia, Africa and South America. • plump reddish brown oval worm • 10 by 4 mm

  34. MOT: INGESTION OF METACERCARIAE

  35. Paragonoimus • migrate by penetrating through the intestinal wall  peritoneal cavity abdominal wall  diaphragm  lungs. • immature worms settle close to the bronchi  grow  sexually mature hermaphrodite worms  eggs

  36. Paragonimus westermani: lung tissue

  37. Paragonimus • dry cough • blood stained rusty brown sputum • pulmonary pain and pleurisy • Brain: granulomatous abscess  epilepsy

  38. Paragonimus • Diagnosis Eggs are found in rust colored sputum • Treatment and controlPraziquantel • Adequate cooking of crustaceans • Improved sanitary conditions

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