Entrobius vermicularis

Lecture include: introduction, morphology, life cycle,symptoms, lab diagnosis, treatment, prevention and control

1. Entrobius vermicularis The pinworm Lecture by: Maha Gamal Aldein

2. Introduction Enterobius vermicularis is a nematode worm commonly known as pinworm. This because it has sharp & pointed posterior end(like pin), or may be also due to pinpricks sensation experienced by infected people. I nhabits human large intestine Causing the disease known as Enterobiasis. 2

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4. Geographical distribution: There is a worldwide distribution of pinworm infection 4

5. Morphology (the worm) Shape : round Color : white Size: Females : 8 to 13  mm long males: 2 to 5mm long posterior end: Tapered in females curved in males anterior part(cervical alae ): found in both male and female worms 5

6. Cervical alae : is a wing –like cuticle expansion in the anterior part of male and female worms 6

7. Eggs of E. vermicularis E.vermicularis are oviparous worms Shape : D shaped Size :50- 60 x 20-30 µm Color : colorless Shell : thin Contents: Single cell ( immature egg) or Larva ( mature egg) 7

8. Development of Entrobius eggs 8 1- E.vermicularis lay the eggs in the perianal skin 2-Eggs are single celled when laid by the worms 3-After 4-6 hours they develop into larvated eggs (infective stage ) 4-The larvated eggs after ingestion by man they develop into worms

9. How man become infected? Human becomes infected by ingestion of infective eggs (contain larva ) The larvae hatch in the small intestine Migrate to the large intestine W here they develop to adults (male & females) After 1 month the females become gravid The worm do not lay eggs in the intestinal lumen They lay eggs in perianal skin (skin around the anus) 9

10. The worms migrates out the colon and lays eggs around the anus at usually night. Each worm lay about 10,000-11,000 eggs The eggs can spread every where and become infective in 4 to 6 hours 10

11. E. v ermicularis worms in the anal area depositing thousands of eggs 11

12. Where we find Entrobius vermicularis eggs??? 12

13. More?? 13

14. Pinworm eggs can survive for up to two weeks on clothing, bedding, food, and other surfaces . Ready to infect other people. 14

15. Life cycle 15

16. Types of infection occur in entrobiasis 1- Infection Occur when healthy person ingest the infective eggs from enviroment 2 -Re- infection (self infection) A person can re-infect themselves from their own ( by ingestion of infective eggs ) 3 -Retro-infection: T his occur when eggs mature and larvae hatch in anal area, this larva can migrate back to the large intestine through the anus, where they grow into mature worms. (larvae are the infective stages) 16

17. Pathology & Symptomatology The most common clinical manifestation of a pinworm infection is N ight itch in anal region because worms lay eggs nocturnal I rritation of the anal area due to scratching Secondary bacterial infection T eeth grinding during sleeping I nsomnia A bdominal pain Frequent defecation 17

18. Epidemiology Although adult can be infected, but the infection is more common in children. Pinworm infections are more common within families with school-aged children Kindergartens and nurseries Orphanages Refugees camps. Mental institutions 18

19. Factor helps spread of infection: The worms deposit large numbers of eggs. The worms lay the eggs of intestine (anal area), where it can spread to environment easily. The e ggs become infective within short time (4-6hours ). The e ggs can remain infective for up to 2 weeks The eggs have a surface that adheres to environmental objects . Poor personal hygiene. 19

20. Complications: Appendicitis: when worms invade the appendix Vaginitis : found in female patient due to invasion of vagina by hatched larva from anal area 20

21. Laboratory Diagnosis 1- what is /are suitable sample/s? 2- what is are suitable diagnostic test/s or technique/s? 3- what is/are the diagnostic stage/s? 21

22. Summary : E. vermicularis worm inhabit human large intestine The worm lay about 1 0,000-11,000 eggs/ day 95-97% of eggs are deposited in the perianal skin Only 3-5% can be found in stool The eggs usually deposited at night while the patient is sleep Sometimes the worm can found in stool. 22

23. 1- Best sample to diagnose entrobiasis is Swab from perianal area Best time for swab: early morning before going to toilet 2- S uitable diagnostic technique: 1- scotch tape technique 2 - anal swab “ swube ’’ 3-NIH swap 3-diagnostic stages: A- eggs & a dults worm 23

24. 1-Scotch tape technique Principle: the eggs of E. vermicularis can be collected from the perianal skin using a piece of transparent adhesive tape. 24

25. procedure Firmly press the sticky side of the cellophane tape over the skin surround the anus several times. The eggs will stick to the tape. The tape is then placed on glass slide, sticky side down. Put drop of glycerol, examine the slide under the microscope. Precaution: Put on gloves because eggs are directly infective. 25

26. 2- Anal swab ‘’ Swube " is a modification of scotch tape, paddle coated with adhesive material has advantage of scotch tape and glass slide. 26

27. Can we find Entrobius eggs in other specimens? 1- Very few eggs sometimes found in stool 3- Urine of the infected females 4- V aginal secretion in case of vaginitis caused by the worms 27

28. Treatment Several medications used for the treatment of pinworm are: M ebendazole P yrantel pamoate A lbendazole All three of these drugs are to be given in single dose and then repeated 2 weeks later. Prognosis The prognosis is good 28

29. Prevention & control 1- Washing hands with soap & water (after using toilet, Before eat) 2- Trimming nails regularly & avoid biting the nails 29

30. 3- Avoid scratching anal area . 4-Showering every morning and washing the anal area( to remove the eggs) 30

31. 5- Do not co-path with infected people 6- Cleansing bathroom & toilet 31

32. 7 -Washing cloth and bed linens with hot water, to kill the eggs. 8 - Ironing , or expose them to sunlight for 24 hours to kill the eggs 32

33. 9- Treatment of infected individuals. In institutions, day care centers, and schools, control of pinworm can be difficult, but mass drug administration during an outbreak can be successful. 10- Avoid ready made foods & drinks 33