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Rotavirus have been reported as the principal causal pathogen of acute gastroenteritis and one of the leading causes of child morbidity and mortality in Egypt .This study aimed to investigate biological , serological and molecular Rotavirus genotypes infection in Egypt . The blood and stool clinical specimens were collected randomly from 100 patients .They were analyzed for the presence of antigen and the antibody using enzyme-linked immunosorbent assay (ELISA). Rotavirus antigen in stool and antibodies in serum were detected by ELISA among Children (78.13); Female (12.5 ) and male (9.38%). Rotavirus titer was determinated as 5.5x10 7 ; 6.0x10 6 and 7.5x10 7 (PFU\ml) on vero cell of Female ; male and children respectively after 4 days Post infection. The cytopathic effects were granulation of cytoplasm , enlarged , swelling , rounded and multinucleated giant cells .The virus particles are non-enveloped with Icosahedral symmetry with about 70 nm in diameter .Rotavirus isolates showed homologous with RV isolates recorded in gene bank based on alignment and phylogenetic tree analysis. Six RV genotypes (G1P4, G1P6, G1P8 , G9P6 , G1P8, G3 P8) were detected in summer. Seven RV genotypes, (G1P4, G1P6, G1P8 , G3P4 , G3P6, G3P8 G9P8) were detected in in spring and five RV genotypes (G1P4, G1P8 , G3P4, G3P8 G9P8) were detected in winter seasons . SDS-PAGE showed seven structural and function of proteins were polymorphism variation among for Rotavirus isolates . RV genomic migration pattern of G1P4, G1P6, G1P8 , and G9P8 were varied in number , density and segmented to 12 , 9 , 10 , and 9 moved respectively .

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Background: SARS-CoV-2 genome encodes different kinds of structural and nonstructural proteins. The spike structural protein is the prime target for vaccine manufacturing, drug development, and diagnostic assays.Methods: In this cross-sectional study, we assessed the developed Receptor Binding Domain (RBD) protein in 520 serum samples. The samples were stratified according to vaccine status into two groups: Group 1 consisted of 274 pre-vaccinated samples collected from April to December 2020 (109 were asymptomatic contacted with COVID-19-patients; 100 patients had positive RT-PCR test for SARS-CoV-2 infection, and 65 were convalescent-COVID-19 cases), and group 2 consisted of 246 post-vaccinated participants with or without past-infection recruited from students, coworkers, and staff members from November 2021 to March 2022. Indirect Enzyme-Linked Immunosorbent Assay (ELISA) was performed to evaluate the seroprevalence of the SARS-CoV-2 immunoglobulin G (IgG) across both groups.Results: The sensitivity and specificity of the RBD-developed protein were 88.4% (95% CI: 84% -92%) and 100% (95% CI: 88%-100%), respectively in the pre-vaccinated group. 213 out of 274 of the pre-vaccinated samples were positive. Meanwhile, the RBD-developed protein provided 100% RBD IgG seropositivity in the recovered COVID-19 cases. Moreover, the results were seropositive in all postvaccinated candidates (n=246) and the results were reliable in 70 negative pre-pandemic sera specimens. Conclusion:The developed S-RBD protein has the potential to be a successful screening method in COVID-19-vaccinated or infected individuals.