- Aka: Giardia lamblia or Giardia duodenalis
- most common protozoal cause of chronic diarrhoea
- Transmission: Fecal-oral, waterborne infection
- Life Cycle
- Stage 1: Cyst transmitted via fecal-oral route
- May remain viable for months in moist environment
- can survive in chlorinated pools and hot tubs
- Cyst develops into 2 trophozoites in acid Stomach
- Stage 2: Disease-causing trophozoite
- Trophozoites attach to wall of Small Intestine
- Trophozoites multiply and some transform to cysts
- Cysts are passed with feces to restart cycle
- Risk Factors
- Poor sanitation
- Close contact with source case
- Daycare outbreaks are common
- Sexually-transmitted infection (oral-anal sex)
- Wilderness travel with ingestion of contaminated water
- Exposure to infected animals (zoonosis): Cattle, Dogs, Rodents, Bighorn Sheep
- Symptoms
- Asymptomatic in 50% of those infected
- Timing
- Onset delayed 5-25 days after exposure
- Diarrhea illness persists 1-3 weeks
- Diarrhea may persist with intermittent exacerbations
- Characteristics
- Diarrhea without blood or mucus
- Steatorrhea. Flatulence, Abdominal Pain, Belching, Malabsorption, Weight loss may be significant
- Less Common findings
- Nausea or Vomiting, DehydrationFever suggests other diagnosis
- Treatment
- Immunocompetent/asymptomatic Giardia intestinalis carriage
- symptomatic patients:
- tinidazole 2 g (child: 50 mg/kg up to 2 g) orally, as a single dose OR
- metronidazole 2 g (child: 30 mg/kg up to 2 g) orally, daily for 3 days OR
- metronidazole 400 mg (child: 10 mg/kg up to 400 mg) orally, 8-hourly for 5 days.
- Symptom recurrence after treatment may be caused by :
- postinfection lactose intolerance
- reinfection
- drug resistance
- Prevention
- Avoid swimming in pool for 3 weeks after resolution (asymptomatic shedding persists for 1-3 weeks after resolution)
- Water Disinfection
- Use only bottled water in endemic areas if possible
- Intermediate halogen resistance to (Iodine, Fluorine)
- Use halogen for longer time before drinking
- Use Iodine purification tablets for >8 hours
- Boil water for 1 minute or heat to 158 F x10 minutes
- Water Filtration
- Ensure adequate sanitation system of water treatment
- Prevention in daycare settings
- Dispose of diapers properly
- Frequent and thorough Hand Washing
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