Prevalence of Entamoeba histolytica/Entamoeba dispar complex in a group of Saharawi children

An epidemiological study to characterize Entamoeba histolytica/Entamoeba dispar isolates from 90 asymptomatic human subjects belonging to Saharawi population was performed. The subjects were guested for two months during the summer in Northern-Central Italy (Tuscany and Liguria regions). The coproparasitological examination was positive in 79 subjects (87.8%), most of which showed more than one parasitic species. In vitro culture in Robinson's medium revealed amebic parasites in 63 (80.7%) of the 78 cases tested. 28 isolates (44.4%) were morphologically attributable to E.histolytica/E.dispar complex. The stool antigen detection assay for the identification of E.histolytica/E.dispar complex (TRIAGE® Micro Parasite Panel, Biosite Inc., San Diego, USA) performed on 28/63 in vitro cultures (44.4%) revealed high sensitivity and specificity, showing a positive result in all cases subsequently identified as E.dispar by isoenzyme analysis and PCR. Similarly, the second generation monoclonal-based ELISA specific for E.histolytica galactose-inhibitable lectin (E.histolytica II®, TechLab, Blacksburg, USA) demonstrated a specificity of 100%, showing negative results in all cases tested. Therefore, the present investigation confirmed that diagnostic methods more specific and sensitive than microscopy are needed to distinguish E.histolytica from E.dispar, at least in asymptomatic carriers, and confirms that the latter more frequently infects humans.