2. Nematoda:

3. Structure of the adult : 1.Nematodes are generally elongate, cylindrical, and tapered at both ends. 2. The basic body design is a tube within a tube, male are also usually smaller than females.

4. Structure of egg : Eggs of parasitic nematodes ordinarily consist of three layers : A) Embryo member: consist of lipid protein; B) Chitonous layer : consist of chitonous and protein, and Process the function of resisting the mechanic pression, C) Lipid layer/ascaroside : consist of lipid protein and ascaroside, and process the function of regulating.

5. The character of life cycle: 1 、 The basic process of development :egg, larva and adult. ( growth occurs with molting )

6. 2.The type of life cycle: （ 1 ） Some parasitic nematodes have simple life cycle, consisting of egg, larva, and adult worm, these nematodes are considered as direct development type of nematodes or soil- transmission nematodes, such as hookworm. (2) Some parasitic nematodes need intermediate host to complete the life cycle, these nematodes are called vector transmission nematodes or bio-source nematodes, such as filaria.

7. Ascaris Lumbricoides

8. Ascaris is the most common and largest nematode parasite of humans, infecting an estimated 1.47 billion individuals. Pathology can result from pneumonia caused by the worm's migration through the lungs, blocking of the gastrointestinal track or the bile or pancreatic duct. Ascaris lumbricoides is physically indistinguishable from Ascaris suum.

9. size: 20~35cm×3~6mm 15~31cm×2~4mm Adult : Morphology

10. adult adult

11. 2.Head :. lips

12. tooth lips

13. tooth

14. The tail of male : spicules The tail of male : spicules spicules

15. 3 、 reproductive system

16. Protein membrance shell Embryo Embryo cell gap Fertilized egg Egg

17. fertilized egg

18. fertilizedegg fertilized egg

19. Yolk granule unfertilizedegg unfertilized egg

20. Embryonated egg larvae

21. Life cycle:

22. Larvae must migrate to lungs: Small intestine Heartbronchus trachea throat stomach Moult twice 1w swallowed Penetrate intestinal wall liver lung Small intestine

24. 3. The female parasite is highly prolific. 1. have a direct lifecycle, with no intermediate hosts. 2. Larvae must migrate to lungs. The character of life cycle ：

25. Pathogenesis and clinical manifestations: Larvae: 1 、 Loeffer’s syndrome: large numbers of larvae are migrating through the lungs simultaneously.this may give rise to a severe haemorrhagic pneumonia. lead to breathing difficulties, fever etc.

26. 2、 larvae may migrate to other organ:brain,liver,kidney and thyroid gland etc.

27. Adult : 1. Intaking nutrients and negatively affect the absorption: 2.Allergy: urticaria,itch and angioneurotic edema

28. 3.Complication of ascariasis: 1)mechanical blockage of the intestine: 2)migrate to the bile duct, migrate to the appendix, or through the intestinal Wall:

29. Ascaris （ left 1 、 2 、 3 ）

30. Ascaris in bile duct

31. Ascaris block the intestine

32. Ascaris through the intestinal wall

33. Ascariasis patient

35. Diagnosis: 1.Microscopic exam :egg 2. Chest radiographs for Loffler's syndrome :

36. Epidemiology Distribution: Ascaris lumbricoides is widely distributed in tropical and subtropical areas, especially in the developing countries of S. America where poor hygiene and inadequate sanitation facilities prevail., Africa and Asia. It is estimated that there are more than 1 billion infections at any given time.

37. Distribution of china

38. Epidemiologic factors: （ 1 ） The life cycle of ascaris involves no intermediate host. A female worm has a high reproductive capacity of 26 million eggs, and an average daily output 200,000: （ 2 ） the egg process the strong ability to resist environmental conditions:

39. The promiscuous defecation or night soil used for fertilization provides the source of soil and vegetable contamination. Domestic animals such as fowls and dogs may act as mechanical carriers of the ova. (3) Human feces is used as fertilizer:

40. Prophylaxis 1.Good sanitation : a.Wash hands with soap and water after using the toilet and before handling food. especially when traveling in developing countries. b.Wash and peel all raw vegetables and fruits before eating. Avoid food that may be contaminated with feces. c. Clean, sanitary toilet facilities must be provided. 1.Good sanitation : a.Wash hands with soap and water after using the toilet and before handling food. especially when traveling in developing countries. b.Wash and peel all raw vegetables and fruits before eating. Avoid food that may be contaminated with feces. c. Clean, sanitary toilet facilities must be provided.

41. 2.The drugs of choice for treatment : albendazole, mebendazole, pyrantel pamoate and Fructus guisgualis tab. of Melis toosendan etc.

43. Trichuris trichiura ( Whipworms )

44. Morphology:

45. adult of whipworms in intestine

46. 2 、 Egg :

47. Life cycle: Like that of ascaris lumbricoides: 1. Site of inhabitation:cecum 2. Larvae may not migrate to lungs

48. Pathogenesis and clinical manifestations: when the worm burden exceeds 100 worms. It causes chronic hemorrhage/bleeding resulting in anaemia. In addition there are often secondary bacterial infections which result in colitis, proctitis and in rare cases, can result in the prolapse of the rectum.

49. Rectal prolapse

50. Diagnosis,epidemiology and prophylaxis: Like that of ascaris lumbricoides

51. Distribution of whipworms in china

52. Enterobius Vermicularis (The human pinworms)

53. Morphology 1 、 Adult

54. Bulbed oesophgus anterior end

56. 2 、 Egg eggshell larvae

57. Egg

59. Pathogenesis and clinical manifestations 1. perianal pruritus(especially at night): 2. pinworms migrate through the genital tract of females to the peritoneal cavity.

60. 1.Microscopic identification of egg:Microscopic identification of egg: 2. found adult worm in the perianal area :found adult worm in the perianal area : Laboratory Diagnosis: Eggs are found in feces in only about 5% of cases

61. The worm has a cosmopolitan distribution. Enterobiasis is more common in urban than in rural areas. and is more common in children (escpecially in nursery or kindergarden) Mode of infection: Epidemiology 1 、 hand-to mouth transmission : 2 、 Inhalation of air borne egg in dust: 3 、 retroinfection through the anus:

62. Epidemic factor: 1.The parasite have simple life cycle: 2.The egg can prevent injury of surrounding: 3.The children have bad sanitation :

63. Distribution of age

64. 1 、 good sanitation ： 2 、 The drug of choice ： albendazole menbendazole Prophylaxis: