Diagnosis of intestinal amebiasis using salivary IgA antibody detection.

This investigation sought to determine whether detection of salivary IgA antibodies to Entamoeba histolytica could identify intestinal amebic infections among 223 school children. Four groups of children were identified through coproparasitoscopic examination: E. histolytica as other parasites only (20%); and parasite-free (25%). The diagnostic accuracy of salivary IgA antibodies to an E. histolytica membrane extract was 91.5% (sensitivity, 85%; specificity, 98%), maintaining high predictive value at different prevalences. Also, a positive correlation (r = .753, P less than .001) was observed between fecal E. histolytica membrane antigen levels and salivary IgA antibody activity. Measurement of IgA antibodies in saliva may be useful in diagnosing intestinal infections with E. histolytica within a wide range of prevalences. Moreover, sampling of saliva may be a useful non invasive test for immunoepidemiologic surveys.