Ambeiasis

(Travelers' Health)

Description

Amebiasis is caused by the protozoan parasite Entamoeba histolytica. Infection is acquired by the fecal-oral route, either by person-to-person contact or indirectly by eating or drinking fecally contaminated food or water.

Occurrence

Amebiasis occurs worldwide, especially in regions with poor sanitation.

Risk for Travelers

For travelers to low-income countries, risk for infection is highest for those who live in or visit rural areas, spend time in backcountry areas, or eat or drink in settings of poor sanitation.

Clinical Presentation

The incubation period is commonly 2-4 weeks but ranges from a few days to years. The clinical spectrum of intestinal amebiasis ranges from asymptomatic infection to fulminant colitis. Entamoeba dispar, which is nonpathogenic, cannot be distinguished from the pathogen E. histolytica by routine microscopy; however, an enzyme immunoassay kit for distinguishing the two organisms is commercially, but not widely available. In persons infected with E. histolytica who are symptomatic, the most common symptom is diarrhea. The diarrhea can evolve to painful, bloody bowel movements, with or without fever (amebic dysentery). Occasionally, amebiasis causes disease outside the intestinal tract, most notably in the liver (amebic liver abscess).

Prevention

No vaccine is available. Travelers to low-income countries should be advised to follow the precautions detailed in the section Risks from Food and Drink and avoid sexual practices that may lead to fecal-oral transmission.

Treatment

Travelers may be advised to consult with an infectious disease specialist to ensure proper diagnosis and treatment. Iodoquinol or paromomycin are the drugs of choice for asymptomatic but proven E. histolytica infections. For mild or moderate to severe intestinal disease and extraintestinal disease (e.g., hepatic abscess), treatment with metronidazole or tinidazole (not yet available in the United States) should be immediately followed by treatment with paromomycin or iodoquinol.

Health Information for International Travel 2003-2004

© 2003