RNT lecture 2012 Worms of the large intestine


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RNT lecture 2012 Worms of the large intestine

  1. 1. 1Worm infectionsof the large intestineRahajeng N. Tunjungputri, MD, MScDepartment of ParasitologyFaculty of Medicine Diponegoro University2012
  2. 2. Outline2  Epidemiology  Trichuris trichiura  Enterobius vermicularis  Gastrodiscoides hominis
  3. 3. Epidemiology – Trichuris trichiura3  800 million people infected worldwide  Children living in poverty in the tropics and subtropics  It is most common in poor rural communities and areas in which sanitary facilities are lacking and hands, food, and drink are easily contaminated  Many people harbor infections with both Trichuris and Ascaris  In up to 10% of patients in endemic areas worm burden may be high (up to 200 worms/pts) and suffering from disease  Genetic studies: 25% of the variation in susceptibility to infection with T. Trichiura is due to genetic factors
  4. 4. Worldwide distribution of T. trichiura4
  5. 5. Epidemiology – Enterobius vermicularis5  Enterobius vermicularis, or pinworm, is highly prevalent throughout the world  infecting about 10% of population in developed countries, the infection rate in children is even higher  US: E. vermicularis is the most common of all helminthic infections (42 million cases in 1980s); prevalence 15-50% in children  Pinworm infection is particularly common among:  Children, institutionalized groups, and households  not associated with socioeconomic level
  6. 6. Major intestinal nematodes6
  7. 7. Trichuris trichiura7 The development to adult worms is about 3 months  there may be no shedding of eggs in this period Worms live approx. 3 years Adult worms inhabit the caecum and colon  May extend in severe infection Transmission
  8. 8. 8  Whip-like structure  Adult: the anterior 3/5 is slender and the posterior 2/5 is thick  Thin anterior portion: has capillary-like esophagus, embedded in the mucosa  The posterior end: lies free in the intestinal lumen  After mating, the female worm produces 7000 to 20,000 eggs/day  Eggs are barrel shaped, bile stained with bipolar plugs
  9. 9. Adults of T. trichiura9
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  11. 11. Eggs of T. trichiura under the high power11
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  15. 15. Trichuriasis15  Most people: asymptomatic, eosinophilia  In heavy infections, the mucosa is inflamed, edematous, and friable, and increased TNF-α  growth retardation and impaired cognitive function  Children with chronic Trichuris colitis:  chronic abdominal pain and diarrhea  iron deficiency anemia  growth retardation  dysentery syndrome: tenesmus and frequent passage of stools containing large amounts of mucus and often blood  Recurrent rectal prolapse is common
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  18. 18. Barium enema, air contrast18
  19. 19. Diagnosis19  Trichuriasis  Finding eggs in stool (level of egg output is high)  Identifying the adult worms on the mucosa of the prolapsed rectum  Findings of worms in colonoscopy  Occasionally by air contrast barium enema in massive infection
  20. 20. Treatment20  Single doses of albendazole, mebendazole, and pyrantel pamoate cure less than 50% of patients  Light and moderate infection:  Three days of albendazole (400mg PO/day)  Severe infection  5-7 days of albendazole
  21. 21. Enterobius vermicularis21  E. vermicularis is a small white worm measuring 1 cm in length  inhabiting the cecum, appendix, and adjacent gut  Enterobius ova are ovoid but flattened on one side and measure approximately 56 × 27 μm
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  24. 24. E. vermicularis life cycle24 Hatch in the duodenum 5 or 6 weeks  develop into adult worms (max. 1 mo) Gravid female worms  Contain 10,000 ova/each  Migrate at night to the perianal and perineal regions to deposit egg  itching Eggs mature in 6 hrs (due to O2) Eggs are transferred and attached to bedding, linnen etc
  25. 25. Transmission of enterobiasis25  The modes of transmission are:  viathe hands of the patient (underneath the fingernails) through frequent scratching  autoinfection  Transmission through eggs viable on  Direct exposure of eggs to clothes, bed linen, fabrics  Contaminated dust on objects  Walls of school hall, classroom, toilets  Toys, furnitures  Sexual partners engaging in oral-anal sex  Larvae migrate into the sigmoid colon  retroinfection
  26. 26. Enterobiasis26  Most: asymptomatic  Perianal and perineal pruritus and scratching  restlessness, secondary infection  Vulvovaginitis, vaginal discharge  Migration of the parasite may lead to ectopic disease, such as pelvic, cervical, vulvar, and peritoneal granulomas  mimicking pelvic mass/ PID  Studies: more normal than inflamed appendices removed at surgery for suspected appendicitis contained pinworms  symptoms resembling appendicitis without invasion of the mucosa
  27. 27. Appendix27
  28. 28. Case report28  A 13 year old girl presented to the emergency room with a five day history of vomiting, diarrhoea, fever, and abdominal pain. She was not sexually active  In her spare time she earned money as a babysitter for 6–12 year old children  Physical examination revealed signs of peritonitis; leukocytosis and eosinophilia  USG: fluid in the peritoneum  Laparoscopy  pathology
  29. 29. 29  The patient was treated with two 400 mg doses of albendazole administered one week apart.  The family contacts also received a dose of mebendazole.
  30. 30. Diagnosis30  Microscopic examination of an adhesive cellophane tape pressed to the perianal area early in the morning before bathing or defecation (eg. By parents)  A single examination detects 50% of infections, three examinations detect 90%, and five examinations detect 99%
  31. 31. Treatment31  Single doses of one of the followings:  albendazole (400 mg)  mebendazole (100 mg)  ivermectin (200 μg/kg)  pyrantel pamoate (11 mg/kg up to 1 g) are highly effective. A second dose is given 2 weeks later because of the frequency of reinfection and autoinfection  Other infected patients should be treated
  32. 32. Gastrodisciasis32  Caused by Gastrodiscoides hominis reported from Assam state in India, Bangladesh, Phillipines, SEA countries, Nigeria  Morphology:  a ventral sucker located in the posterior end  the anterior region is narrow and ends with a rounded tip.  the posterior region contains the reproductive organs including an ovary in the shape of an oval located under the 2 lobed testes  Eggs are similar to Fasciola spp. but larger
  33. 33. 33 Definitive hosts:  Human, pigs, rats Intermediate hosts:  IH1: Snails  IH2: Water plants India: water caltrops thrive in ponds fertilized by “night soil” (human feces) Transmission: ingestion of metacercaria in plants
  34. 34. Gastrodisciasis34  Clinical sign  Usually asymptomatic  Occasionally diarrhea, fever, abdominal pain, colic, and an increase in mucous production  Diagnostics  Stool examination  Treatment  Praziquantel
  35. 35. Prevention35  Treatment of patients and infected people with frequent contacts  Other infected family members, classmates, or residents of long-term care facilities should be treated at the same time as the index case  repeated treatment courses may be needed  Maintenance of hygiene and sanitation (hand washing)  Cleaning surface area, bed sheets, clothes, towels; preventing the spread of eggs
  36. 36. Research application36  Trichuris has been shown to secrete molecules that induce antiinflammatory cytokines  It appears that infection with eggs of the porcine whipworm Trichuris suis may lead to improvement of inflammatory bowel disease  characterization of the responsible immunomodulatory molecules could lead to new therapeutic approaches
  37. 37. Discussion37