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

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 westermaniP. skrjabini • Blood fluke: Schistosoma spp.

13. The Liver Fluke肝吸虫Clonorchis sinensis中华支睾吸虫

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

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.)

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 • praziquantel:25mg/kg, tid, 2 days • Control reservoir host • Carry out scientific fish-breeding • Hygienic educationnot eating raw or undercooked fishes

34. Paragonimus westermani卫氏并殖吸虫Paragonimus skrjabini(Paragonimus szechuanensis)斯氏狸殖吸虫

35. The Lung Fluke • Genus paragonimus • Zoonotic parasite (cause zoonosis) • Animal infection> 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)

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 host:I: 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

46. Pathogenesis • Stage take responsibility: adult & preadult • Pathological processes • Abscess stage(脓肿期) • Cystic stage(囊肿期) • Scar formation stage(纤维疤痕期)

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).