Diagnostic potentials of copro-antigen detection based ELISA, compared to microscopy in intestinal amoebiasis.

Ninety three patients clinically presumed to have intestinal amoebiasis were chosen and stool samples were collected from all of them. Stool samples were subjected to microscopic examination and Entamoeba copro-antigens detection using Entamoeba and Entamoeba II tests. Out of 93 clinically positive samples, 51 (54.8%) were found positive by microscopy, while 49 (52.7%) were detected by Entamoeba test as having antigens specific for E. histolytica/E. dispar (88.24% sensitivity). Among 49 specimens, 4 were demonstrated as microscopy negative (90.48% specificity). Entamoeba II test demonstrated 16 specimens having antigens specific for the pathogenic E. histolytica among 49 positive by Entamoeba test, while 33 were detected as positive for nonpathogenic E. dispar copro-antigens. Copro-antigen assay using ELISA has shown to be more sensitive and specific than microscopy in different-tiation between pathogenic and nonpathogenic Entamoeba species. Extensive use of this technique allowed for revising the epidemiology of the true pathogenic E. histolytica and obviate the need for unnecessary chemotherapy with its costs and risk of side effects.

Selective identification of the pathogenic E. histolytica in fresh stool samples using polymerase chain reaction (PCR).

Stool samples from 93 individuals clinically presumed to have intestinal amoebiasis and subjected to microscopic examination and DNA extraction. The PCR amplification was performed using two sets of primers that differentiate between pathogenic and nonpathogenic Entamoeba DNA. Of 93 clinically positive cases, 51 (54.8%) were positive by microscopy, while 53 (56.9%) were detected by PCR as having DNA specific for either E. histolytica / E. dispar. A specificity of 85.71% and a sensitivity of 92.15% were with PCR compared to microscopy. Among 53 PCR positive specimens, three different DNA sequences were demonstrated: 8 specimens had DNA sequences specific of E. histolytica, 31 with DNA specific for E. dispar and 14 specimens have mixed DNA sequences for E. histolytica and E. dispar. PCR is a sensitive and a specific tool. PCR application is better the epidemiology in endemic areas through keeping indefinite DNA records for prospective and retrospective studies.