Abstract
Giardiasis is a prevailing intestinal disease in children. This study aimed to determine molecular prevalence of Giardia intestinalis in children attending Cairo University Pediatrics Hospitals, using copro-PCR assays, conventional methods and to evaluate diagnostic effectiveness of used tests. 229 fecal samples were collected from children suffering from gastrointestinal symptoms and examined for Giardia by microscopy, Immuno-chromatographic test (ICT), copro-DNA using two PCR assays targeting tpi [nested-PCR (nPCR)] and 18S [conventional-PCR (cPCR)] genes. Out of 229 samples assessed, Giardia was diagnosed in 13.9, 17, 17.9, 4.8 % of cases using microscopy, ICT, nPCR (tpi) and cPCR (18S), respectively. Nominating both PCR assays as composite reference standard, microscopy and ICT were of reliable specificity (100 and 96.9 %) and accuracy (95.6 and 93.6 %) but of limited sensitivity (78.6 and 76.2 %). Kappa agreement showed, there was substantial agreement of ICT (0.776) and almost perfect agreement of microscopy (0.839) with PCR assays. Giardia showed a molecular prevalence of 18.3 % (42/229). ICT assay for Giardia surpassed microscopy but both couldn't be used as a consistent single detection method due to their lowered sensitivities. nPCR targeting tpi is a reliable diagnostic test aiding to determine true prevalence of Giardia.