Giardiasis

Description

Giardiasis is a diarrhoeal illness caused by the protozoan Giardia intestinalis, which lives in the intestines of persons and animals and is passed in their feces. Transmission occurs from ingestion of faecally contaminated food or drinking water, swallowing recreational water, from exposure to faecally contaminated environmental surfaces, and from person to person by the faecal-oral route.

Occurrence

Giardiasis occurs worldwide.

Risk for Travellers

Risk of infection increases with duration of travel and is highest for those who live in or visit rural areas, trek in backcountry areas, or frequently eat, drink, or swim in areas that have poor sanitation and inadequate drinking water treatment facilities.

Clinical Presentation

Symptoms, which occur approximately 1-2 weeks after ingestion of the parasite, include diarrhoea, abdominal cramps, bloating, fatigue, weight loss, flatulence, anorexia, or nausea, in various combinations. Symptoms usually last >5 days and can become chronic, resulting in malabsorption. Fever and vomiting are uncommon.

Prevention

No vaccine is available, and there is no known chemoprophylaxis. To prevent infection, travellers to disease-endemic areas should be advised to follow the precautions included in the section Risks from Food and Water.

Treatment

Several effective antimicrobial drugs (e.g., tinidazole, metronidazole, quinacrine, albendazole, nitazoxanide) are now available. Treatment recommendations are available in textbooks on internal medicine and infectious diseases; consultation with a travel or tropical medicine specialist can also be sought.

Bibliography
  • Hardie RM, Wall PG, Gott P, et al. Infectious diarrhoea in tourists staying in a resort hotel. Emerg Infect Dis. 1999;5:168-71.
  • Stuart JM, Orr HJ, Warburton FG, et al. Risk factors for sporadic giardiasis: a case-control study in southwestern England. Emerg Infect Dis. 2003;9:229-33.

- Michael Beach

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