Amebiasis. The ancient scourge is still with us.

Amebiasis is usually contracted in geographic areas where sanitation is poor, but outbreaks can still occur anywhere that drinking water becomes contaminated with sewage. In the majority of persons infected with the parasite, colonization of the intestine is asymptomatic. In others, symptoms of gastrointestinal distress can appear within a week. In rare cases, extra-intestinal amebiasis can cause abscesses in the liver or elsewhere. Many questions about the disease course in different patients remain to be answered. Diagnosis can be made through symptom identification; findings of right-upper-quadrant tenderness, leukocytosis, and an elevated level of alkaline phosphatase; and testing the feces for trophozoites or cysts. Clinicians disagree on whether asymptomatic persons need to be treated, but anyone who is capable of transmitting the disease should be advised of how to avoid exposing others to it.