Immunologic tools in the diagnosis of amebiasis: epidemiology in the United States.

Several immunodiagnostic tests that detect antibody to Entamoeba histolytica are now available. Such tests are useful when demonstration of the etiologic agent is difficult (as in liver abscess), when routine diagnostic tests fail to disclose the organisms (as in severe intestinal disease compromised by failure of the laboratory to identify the organism or by the patient's use of interfering substances), and as epidemiologic tools for determining the prevalence of invasive disease in populations. Knowledge of the prevalence of amebiasis in the United States is incomplete because the disease is not routinely reported. Information currently available on the prevalence of amebiasis has accumulated from studies of selected groups that include children, institutionalized persons, members of extended families, immigrants, and male homosexuals.