Enterobius vermicularis(pin worm)

Enterobius vermicularis(pin worm)

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  PRESENTED BY: Man Bdr.Rana BPH,ACAS,Nepal
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  INTRODUCTION :  Enterobiusvermicularis is a nematod (roundworm) and a common intestinal parasite in humans.  It has round body with cylindrical ends and a complete digestive system including mouth and anus.  It has separate sesex,the female is usually larger then male.  It has a worldwide distribution.
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  MORPHOLOGY :  Thebody is covered with a highly resistant coating called cuticle.  The male worm is inconspicuous and has a length of 2 to 5 mm.  The female is dominant and has length of 8 to 13 mm.
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  LIFE CYCLE :
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  Contd.  Humans arethe host.  Infection occur by ingesting eggs.  The larvae hatch from the eggs in the small intestine.  The larvae develops into male and female worms.  Fertilization occurs in the colon, after that males die.  Gravid female migrates nocturnally to the anus and lay eggs, after that female die.  The eggs become infectious within 6 hrs.
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  Cont.  The movementof female worm and the eggs cause itching.  Scratching the area may result in retro infection .  The time period from ingestion of infected eggs to the ovideposition is approximately one month.
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  PATHOGENESIS AND CLINICAL FINDINGS.: Perianal pruritus is the most common symptoms.  It is thought to be an allergic reaction to the presence of either the adult female or the eggs.  Itching of the perianal and vaginal area is commonly notable, especially during night.  Weight loss is also observed in severe infections  Scratching predisposes to secondary bacterial infection.
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  EPIDEMIOLOGY :  Foundworldwide, most commonly in USA.  Thumb sucking in and nail biting contributes to the ingestion of eggs.  Children younger then 12 years of age are most commonly affected group.
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  LABORATORY DIAGNOSIS : The eggs are recovered from perianal skin by using the scotch tape technique for microscopic examination .
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  Eggs are notfound in the stool. No serological tests are avilable.
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  TREATMENT :  Mebandazoleand albendazole can be usesd .  These drugs are given in 1 dose at first, the second dose is repeated after 2 weeks.  Topical insecticide containing malathion can be applied on skin.
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  PROPHYLAXIS:  Wash theanal area in the morning.  Change underwear and linen daily.  Launder the bed sheet in hot water.  Don’t scratch and avoid nail biting .  Clean toilet seats daily.  Wash your hand with soap and water.