Giardiasis

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2021年4月27日 (火) 11:00時点におけるVaccipedia.admin (トーク | 投稿記録)による版
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Giardia intestinalis

  • a.k.a. G. lamblia or G. duodenalis
    • 「ランブル鞭毛虫」is named after G. lamblia

epidemiology

  • worldwide
  • human is main reservior
    • beaver in North America
  • water-borne
    • food-borne thru uncooked vegetable or fruit washed with contaminated water
  • feco-oral

life cycle

  • ingestion of cyst
  • hutch in intestinal wall into trophozoite
  • trophozoite propagets in binary fission
  • trophozoite does not invade human cells, just adhere to intestinal mucosa (villi)
    • produces no bloody diarrhea
  • trophozoite transforms into cyst under dry environment
  • cyst is resistant to chlorinated water

morphology

  • 2 nuclei in trophozoite
  • 4 nuclei in cyst

clinical features

  • incubation 3 days to months
  • 10 cysts are enough to develop symptoms
  • most asymptomatic
  • repeated infections induce immunity
  • abrupt onset of diarrhea
  • abd cramps
  • no fatality case

diagnosis

  • fecal microscopy
  • duodenal fluid aspiration
    • "String test"
    • "Crosby capsule"
  • antigen detection in feces
    • ELISA
    • EIA - rapid diagnostic test
  • fluorescence microscopy of feces

treatment

  • metronidazole