الفهرس 
Introduction and aim of the work
TaxonomyOnly 14 pages are availabe for public view
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Abstract
Introduction: Giardia has a worldwide distribution and is emerging as one of the most frequent causes of diarrhea in humans in both developing and developed world. Several alternative methods were tried for Giardia detection in stool instead of relying on microscopy due its lower sensitivity. The aim of the present study was to compare between ordinary microscopy and monoclonal-antibody based methods including direct immunofluorescence assay, ELISA and flow cytometry for Giardia detection in human stool samples. Material and methods: Eighty-four child were included in this study and divided into symptomatic and asymptomatic groups according to their complaints concerning gastrointestinal symptoms. Fecal samples from participants were processed by conventional microscopy with formol-ether concentration technique, Direct Immunofluorescence assay (DIF), ELISA, and flow cytometry (FC). Results: Among 84 fecal samples, 40 (47.6%) were diagnosed as Giardia positive by microscopy. Monoclonal-antibody based DIF, ELISA and flow cytometry detected 52 (61.9%), 52 (61.9%), and 38 (45%) Giardia-positive cases respectively. Sensitivity and specificity of each test was compared with DIF as a gold standard test. Accordingly, ordinary microscopy in this study has a sensitivity of 76.9 %, specificity of 100 %. ELISA test in this study has a sensitivity of 94.23% and specificity of 90.6% for diagnosis of Giardia in stool. FC has a sensitivity of 73.08 % and specificity of 100 %. Conclusion: Although direct microscopic examination requires experienced staff, it is more economical and quick and can also detect other parasites. It should therefore be used as a first choice. DIF is an excellent technique for Giardia detection in cases suspected clinically as giardiasis after negative microscopic examination. ELISA can be used as an alternative to DIF. FC had slightly lower sensitivity than microscopy and conventional flow cytometers are costly, large, and mechanically complex. Recent advances in machine design and capabilities may result in increased utility of flow cytometry for sample analysis.