fbaca13b-fabb-427a-9119-ee5f1bdb0c2c-161115172328.pptx

tgr nenar

1. Intestinal Nematodes : Ascaris lumbricoides , Hook worms, Enterobius vermicularis Dr. njoroge

2. Intestinal Nematodes Systemic classification : Based on Anderson et al. (1974). Two classes – 1. Adenophorea . 2. S ecernentea . Classification based on habitat : 1. Intestinal : i) small intestine – A. lumbricoides A. duodenale Necator americana ii) large intestine – Enterobius vermicularis Trichuris trichura

3. 2. Somatic : i) filarial worm. ii) lymphatics – Wuchereria bancrofti Brugia malayi iii) skin – Loa loa Onchocerca Mansonella iv) others – Tricinella spiralis Dracunculus medinensis

4. Classification based on laying eggs or larva : Oviparous : i) eggs with segmented ovum : hookworm, Trichostrongylus species. ii) eggs with unsegmented ovum : Ascaris species. iii) eggs with unsegmented ovum with mucus plug at both ends : Trichuris species. iv) eggs containing larva : Enterobius species.

5. 2. Viviparous : female worms directly give birth to larvae; there is no egg stage – filarial worm, Tricinella species, Dracuncular species . 3. Ovoviviparous : female worms lay eggs that immediately hatch out – Strongyloides species.

6. Enterobius vermicularis

7. History & Epidemiology : It is first described by Leuckart , in 1865. Globally around 209 million people are infected each year. Prevalence is maximum among the school going children. Temperate climate, over crowding, impaired hygiene, poor personal care are factors promoting infection. Habitat : The adult worm remains attached to the large intestine (caecum, appendix, adjacent portion of colon) by their mouth end.

8. Morphology : Adult worm : 1. Apearance : small, white, tread like. 2. Size : male – 2-5mm x 0.1-0.2mm female – 8-13mm x 0.3-0.5mm. 3. Cervical alae : a wing like expansion of the cuticle near the anterior end. 4. Double bulb esophagus : posterior dilated end of esophagus which forms the globular bulb. 5. Male : posterior end is tightly curved, bearing a copulatory bursa with spicules at the posterior end.

9. 6. Female : posterior one third is tapering, straight, thin and pointed. Eggs : 1. Shape : oval, planoconvex . 2. Size : 50-60µm x 20-30µm. 3. Surrounded by double layered egg shell. 4. Embryonated when passed fresh; contains a tadpole larva inside. 5. Survives some weeks in fairly high humidity and moderate temperaure , few days in dry dust.

10. Life cycle :

11. Clinical feature : Asymptomatic. Symptomatic : - perianal pruritus (cardinal feature). - excoriation of perianal region. - abdominal pain, pruritus. - vulvovaginitis . - pelvic and peritoneal granuloma. - chronic pelvic peritonitis.

12. Pathogenicity : Host : only human. Infective form : embryonated eggs. Mode of transmission : Ingestion of eggs by contaminated hands (nail biting, inadequate hand washing). Exogenous autoinfection : scrapping of perianal region due to intense itching, thus contaminating the finger. Endogenous autoinfection/ retroinfection : retrograte migration of larvae those have hatched at perianal region into rectum and large intestine.

13. Pathogenesis : A. Nocturnal migration of gravid female, fully filled with eggs, from large intestine to perianal region and start laying eggs. Human with hypersensitivity to the secretion and excretion of the worms Rectal pruritus at night Continuous scratching of skin Excoriation of perianal skin

14. B. Migration of the worm Invade female genital tract – vulvovaginitis . Entrance into peritonial cavity – formation of granuloma around eggs or worm which may lead to chronic pelvic peritonitis. 3. Invade appendix – appendicitis. 4. Others : liver, lungs.

15. Laboratory diagnosis : Sample collection : 1. cellophane tape method. 2. NIH swab method. 1 2

16. Microscopy : detect eggs ( planoconvex , 50-60µm x 20-30µm), with a translucent shell of moderate thickness, containing a larva inside.

17. Treatment : One of the followings – Mebendazole 100mg once. Albendazole 400mg once. Pyrantal pamoate 11mg/kg once (max 1gm). ** the same treatment should be repeated after 2 weeks. ** all the family members, including asymptomatic reserviors should be treated simultanously .

18. Prevention : By improving personal hygiene. Proper washing of bed cloths. Hand washing.

19. Ascaris lumbricoides

20. It is the largest nematode parasitizing the human intestine. ‘ Askaris ’ means intestinal worm, ‘ Lumbricus ’ means resembling with common earth worm. Epidemiology : Cosmopolitan in distribution, mainly affecting temperate and tropical countries. 1430 million people are infected each year globally, of which 120-150 millions are symptomatic. Intestinal obstruction due to Ascaris infection is in a range of 0-0.25 in 1000 population in endemic regions; children under 10 years are susceptible with fatality rate of 5.4%.

21. Morphology : Adult worm : Appearance : pinkish creamy. 2. Size : females – 20-30cm, male 15-31cm. 3. Shape : cylindrical with tapering end. 4. Life span : 1-2 years. 5. Mouth part : bears 3 characteristic toothed lips (1 dorsal, 2 ventral). 6. Body cavity : filled with ascaron or ascarase .

22. 7. Alimentary canal : well developed; Mouth at anterior end, muscular and glandular esophagus , intestine and rectum, a subterminal anus. - intestine or midgut is lined by a single layer of columner cells. 8. Nervous system : rudimentary and consists of circular nerve ring; six longitudinal nerve trunk – i) dorsal nerve – motor control. ii) lateral nerve – sensory control. iii) ventral nerve – control both. 9. Killed at excessive heat and dryness; remains viable in moist soil for long period.

23. Male : - slender, incurved tail bearing two spicules at posterior end . - rectum and genital duct open together at cloaca near the posterior end. Female : - straight and pointed posterior end. - anus : subterminal ; situated posteriorly. - vulvar waist : narrower portion at the junction of anterior and middle third of the body on the ventral surface bearing vulva.

24. Eggs : Two types : i) fertilized (45-75µm x 35-50µm). ii) unfertilized (90µm x 40µm). - Clay soils are the most favourable for development of eggs . - ascaroside , a lipoprotein present in egg shell, protect it from disinfectants, and allow it to survive for 15 years. ** Decorticated eggs : when fertilized eggs lose the thick mamilated albuminous coat.

25. Larva : 4 stages - L₁ to L₄.

26. Life cycle : Host : only human. Infective stage : embryonated eggs containing L₂ larvae. Mode of transmission : ingestion of embryonated eggs from the contaminated soil, food, water. Phases : 1. Migratory phase. 2. Intestinal phase. 3. Development in soil.

27. Pathogenesis : Affect due to migrating larva : 2 nd week, after ingestion of eggs Larva migrate into lungs i) Pneumonitis : Provoke immune mediated hypersensitivity Non productive cough, Chest discomfort, Fever.

28. ii) Eosiniphilic pneumonia / Loeffler’s syndrome : In severe cases, sensitive persons develop dyspnea and asthmatic attack. iii) Minor hemorrhage - 20µm larvae get trapped in 10µm alveolar capillaries Break out with consequent hemorrhage . 2. Affect due to Adult worm : Asymptomatic.

29. ii) Symptomatic : In the intestine it liberates antienzymes- antitryptic , antipeptic Protection from digestion by host intestinal ferments 1. Robbing of nutrients- a) malnutrition and growth retardation, b) vit .-A deficiency, c) PEM (in hyperinfected children), d) lactose maldigestion / intolarance .

30. 2. Intestinal complication – a ) bowel obstruction (by forming tangled mass), - abdominal distantion , rebound tenderness, vomiting . b ) perforation, c ) intussusception .

31. 3. Extraintestinal complication - a ) wandering ascariasis : migrate through ampulla of vater into- - appendix : appendicitis. - pancrease : pancreatitis. - biliary tree : biliary colic, cholecystitis . - liver : abcess . - esophagus : coming out though mouth and nose. b ) ectopic ascariasis : migrate to pharynx and block eustachian tube/ rima glottidis causing suffocation.

32. 4. Allergic menifestation : release of body fluid ascaron / ascarase - Typhoid like fever. - Urticaria . - Angioneuratic edema . - Conjunctivitis - Irritation in upper respiratory tract.

33. Laboratory diagnosis : Detection of the parasite : Egg detection : Sample : stool. Microscopy : 1. saline wet mount. 2. iodine wet mount. - both fertilized and unfertilized eggs can be detected.

34. 2. Adult worm detection : occasionally found in stool or sputum by naked eye. Barrium meal X-ray of GIT : ‘trolley car lines’ appearance. USG and cholengiopancreatography : detect adult worm in extraintestinal sites. Giant roundworm in CBD in ERCP. Barrium meal X-ray showing filling defect

35. 3. Larva detection : during early pulmonary migration. Sample : sputum, gastric aspirate. Microscopy : hatching out larva.

36. B. Serology : antibody detection- ELISA. IFA. IHT. Micro precipitation test using larva serology : - in pulmonary phase. - seroepidemiological purpose. C. Others Eiosinophilia : prominent in early lungs stage, disappears later. 2. Presence of charcot layden crystals in stool and sputum.

37. Treatment : Antiparasitic drugs : any one of the followings- Albendazole 400mg once (200mg in children <2years). Mebendazole 100gm twice daily for 3days, or 500mg once. Ivermectine 150-200mg/kg once. Nitazoxanide . Pyrantel pamoate – in pregnancy.

38. B. Symptomatic : Intestinal obstruction : nasogastric suction until vomiting is controlled. Administration of Piperazine 150mg/kg then 65mg/kg twice per day for 3days. 2. Complete obstruction/ intussusception : immediate surgical intervention.

39. Hookworm

40. It is so named because the anterior end of adult worm is bent. Ankylos – hooked, Stoma – mouth. Classification : Family : A nkylostomatidae Subfamily : Ankylostomatinae Subfamily : Uncinariinae Tooth like process Cutting plates Necator americana 2 pairs of teeth 1 pair of teeth 3 pair of teeth Ankylostoma duodenale A. braziliense A. caninum

41. History : A. duodenale 1 st detected by an Italian physician Dublini in 1843 and life cycle and pathogenesis was described by Arthur Loss in 1898. N. americanus was first described by Stites in1902 in Texas,USA , hence called American hookworm.

42. Epidemiology : Globally 900 million people are infected. N. americana infection is more common (835 million). A. duodenale is prevalent in southern Europe, North america , northern Asia. N. americana is prominent in Western world. Both coexist in South east Asia. Males and young adults are commonly affected.

43. Morphology : Adult Worm : Size : A.duodenale – male 5-11mm, female 9-13mm. N. americana – male 5-9mm, female 1cm. Shape : straight except anterior end (bent dorsally). Colour : pink or grayish white; reddish due to ingested blood.

44. Mouth : present anteriorly directed dorsally; contains- A.duodenale : buccal capsule, lined by a hard substance bearing 6 teeth (4 hook like on ventral surface , 2 knob like dorsally). N . americana : 4 chitinious cutting plates (2 ventrally, 2 dorsally ).

45. Glands : digestive system is attached with 5 glands. Vulva : A.duodenale - behind the middle of the body; N. americana – in front of middle of the body. Copulatory bursa : A.duodenale : bifercation is tripartite. rays – 13 dorsal ray splits at the tip. two spicules present freely. N . americana : bifercation is bipartite. rays -14. dorsal ray splits from the base. spicules are fused at the tip.

46. Eggs : - Size : 60µm x 40µm. Shape : oval. Not bile stained, colourless. Surrounded by thin, hyaline, translucent egg shell. Ovum (embryo) is segmented (4 or more blastomeres ). Floats on saturated salt solution.

47. Larva : 4 stages : L₁-L₄. L₁ : rhabditiform larva (100-150 µm ). L₃ : filariform larva (660-720µm)- infective stage. Characteristics A. duodenale N. Americana 1. Size (µm) 720 660 2. Shape Head blunt, tail pointed. Same 3. Cuticle Faint transverse striation. Bears prominent striation. 4. Buccal capsule Shorter, lumen larger, bounded by 2 thin chitinous wall. Larger, lumen short, bounded by 2 thick chitinous wall. 5. esophago -intestinal junc. No gap. Gap present. 6. Intestine Posterior end has a refractile body. Absent.

48. Life cycle : Host : only human. Infective stage : 3 rd stage larvae ( filariform ). Mode of transmission : 1. penetration of skin (most common). i) thin skin between toes. ii) dorsam of the feet. iii) inner side of the sole. 2. percutanous , oral, transmammary , transplacental (in case of A. duodenale ).

49. Phases : 1. migratory phase (10 days). 2. intestinal phase (3- 4 weeks). 3. development in soil (8-10 days). Life span : A. duodenale 1-5 years. N. americana 18 years.

50. Clinical feature : Due to larva : Ground itch and serpiginous tracks. Pneumonitis. Nausea, vomiting, diarrhoea, flatulance . Eiosinophilia : 1350- 3828 cells/ µl.

51. Due to adult worm : Acute infection : rare. Chronic infection : Iron deficiency anaemia : cardiac decompansation characterized by intercurrent infection. Hypoproteinaemia : facial and peripheral edema . Others : Weakness, shortness of breath, impaired intellectual power, behavioural change.

52. Pathogenicity : Penetration is facilitated by : i) proteolytic enzymes ( aspartyl protease). ii) hyaluronidase . B. Ability to suck blood by : attaching and making cuts by buccal capsule and teeth. sucking the blood by muscular esophagus . hydrolytic enzymes. releasing anticoagulants like factor VIIa / tissue factor inhibitor. ingestion of extravasated blood.

53. Pathogenesis : Affect due to migrating larva : 1. local lesion (in previously sensitized persons) : i) At the site of entry Provoke pruritic maculopapular dermatitis and rashes. Ground itch. ii) If after penetration, can not proceed to normal development Do not penetrate below stratum germinativum Subcutaneous migration Serpentine tracks.

54. 2. Mild transient pneumonitis : During migration through lungs Larvae break through the pulmonary capillaries Enter into alveolar spaces Bronchitis, broncho -pneumonia.

55. B. Affect due to Adultworm : Asymptomatic. Anaemia : Heavy worm load Attach and cut intestinal wall by buccal capsule and teeth. Suck blood through contraction of their muscular esophagus . Release factor VIIa / tissue factor inhibitor. Ingestion of extravasated blood. chronic hemorrhage from punctured sites 0.03-0.2 ml blood/ day and 1% Hb per 12 worms are lost .

56. ii) Nutritional defects If associated with iron deficiency – hypochromic microcytic anaemia. If associated with folic acid and vit . B-12 deficiency- macrocytic anaemia. If associated with both – dimorphic anaemia.

57. Laboratory diagnosis : Sample : stool. Microscopy : If sample is fresh : eggs are detected by saline wet mount and iodine mount. - oval, 60µm x 40µm, thin and colourless shell. 2. If sample is kept in room temp. larva may be seen within egg shell.

58. Culture : eggs may hatch out to develop to L₃ in 5-7 days. Methods : Herada Mori filter paper tube. Petridish (slant culture technique). Baermann funnel technique. Charcoal culture method. Agar plate technique (more sensitive).

59. Others : Hypochromic microcytic/ dimorphic anaemia. Eiosinophilia . Hypoalbuminaemia .

60. Treatment : Antiparasitic : any one of the followings- Albendazole 400mg once. Mebendazole 500mg once. Pyrantel pamoate 11mg/kg for 3 days. Symptomatic : Oral iron suppliment . Proper nutritional support with protein.

61. Prevention : Personal care. School based deworming. Improved nutrition status. Treatment of infected persons. Vaccine : - experimental immunization of animals with vaccines using larva or adult stage antigen was found to be effective. - human trials are going on targeting molecules like A nkylostoma secreted protein (ASP)

62. Thank you….