Thesis (M.Sc.) - Cairo University - Faculty of Veterinary Medicine - Department of Animal Diseases

Seventy four chicken, turkey and pigeon flocks were investigated for the presence of NDV using RT-PCR F-protein gene assay, 26 flocks tested positive for NDV. As a preliminary step for the exclusion of lentogenic vaccinal strain positive RTPCR samples were tested by real time reverse transcriptase polymerase chain reaction (rRTPCR) using a probe specific to velogenic strains. Nineteen samples tested positive for vNDV while seven samples tested negative. Twelve samples out of the positive samples were isolated on SPF ECE from eight different Egyptian governorates. Partial sequencing of the F-Protein gene revealed that all isolated strain have multiple basic A.A at the F-Protein cleavage site possessing the velogenic motif (112.RRQKR*F.117). Phylogenetic analysis of the F-protein 375 b.p. hypervariable region (nt 47{u2013} 422), revealed that all isolates are belonging to genotype VIId with (99%-100%) amino acid identity matrix with the Israelian (Turkey-Israel-111-2011) and Chinese (Chicken-China-SDYT03-2011) strain, Genotype VII. Single pure NDV isolated strain was selected APMV1/chicken/EG-BH/POD.CU/2015 (EG.BH/2015) after testing negative for AI common gene, IB, and IBD virus. Titration of the selected strain reveals MDT of (44 hr.) and 107.5 ELD50/ 0.1 ml. In vivo vaccination protection study was done using different vaccination programs for protection against challenge with the locally isolated (EG.BH/2015)

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