Description

Giardiasis is a diarrheal illness caused by the protozoan Giardia intestinalis (also known as Giardia lamblia and Giardia duodenalis), which lives in the intestine of persons and animals and is passed in their feces (1). Transmission occurs from ingestion of fecally contaminated food or drinking water, swallowing recreational water, from exposure to fecally contaminated environmental surfaces, and from person to person by the fecal-oral route.

Occurrence

Giardiasis occurs worldwide.

Risk for Travelers

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 (2,3).

Clinical Presentation

Symptoms, if present, occur approximately 1-2 weeks after ingestion of the parasite. These include diarrhea, abdominal cramps, bloating, fatigue, weight loss, flatulence, anorexia, and nausea, in various combinations. Symptoms usually last longer than 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, travelers to disease-endemic areas should be advised to follow the food and water precautions included in Chapter 2.

Treatment

Several effective antimicrobial drugs (i.e., tinidazole, metronidazole, nitazoxanide, paromomycin, furazolidone, quinacrine) are available. Treatment recommendations are available in textbooks on internal medicine and infectious diseases; a travel or tropical medicine specialist can also be consulted.

References

1. Okhuysen PC. Travelers’ diarrhea due to intestinal protozoa. Clin Infect Dis. 2001;33:110-4.
2. Hardie RM, Wall PG, Gott P, Bardhan M, Bartlett LR. Infectious diarrhea in tourists staying in a resort hotel. Emerg Infect Dis. 1999;5:168-71.
3. Stuart JM, Orr HJ, Warburton FG, Jeyakanth S, Pugh C, Morris I, et al. Risk factors for sporadic giardiasis: a case-control study in southwestern England. Emerg Infect Dis. 2003;9:229-33.