ABSTRACT
Amebic colitis and liver abscess are due to infection with the enteric protozoan parasite, Entamoeba histolytica. This parasite has recently been separated using modern diagnostic techniques from the nonpathogenic parasite E. dispar, which is more common and identical in appearance to E. histolytica [2]. The World Health Organization (WHO) estimates that approximately 50 million people worldwide suffer from invasive amebic infection each year, with a resultant 40,000-100,000 deaths annually [1]. Infection with E. histolytica occurs worldwide, but people living in Central and South America, Africa, and India suffer from the bulk of the morbidity and mortality [2,3]. Carefully conducted serological studies in Mexico, where amebiasis is endemic, demonstrated antibody to E. histolytica in 8.4% of the population [4]. In the urban slum of Fortaleza, Brazil, 25% of the people tested carried antibody to E. histolytica; the prevalence of antiamebic antibodies in children aged 6-14 years was 40% [5]. A prospective study of preschool children in a slum of Dhaka Bangladesh demonstrated new E. histolytica infection in 39% of children over a 1-year period of observation, with 10% of the children having an E. histolytica infection associated with diarrhea and 3% with dysentery [6].
