الفهرس 
INTRODUCTION & AIM OF WORKOnly 14 pages are availabe for public view
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Abstract
Newcastle disease virus (NDV) is prevalent in Egypt, and outbreaks are ongoing. Although extensive vaccination programmes, high mortality (which can approach 100% in velogenic strains of NDV) causes significant economic losses in the chicken sector. Since 2011, NDV outbreaks have occurred in a number of poultry farms, both vaccinated and unvaccinated, in several governorates, generating severe respiratory and neurological symptoms, large mortalities, and substantial economic losses in Egypt’s 3–4-week-old broiler chicken industry. In Egypt extensive vaccination strategies being carried out in the field, Over a breeder’s lifetime, both live and killed boosters are given to ensure strong maternal antibodies. Throughout the current study, samples were taken at various times and from various locations throughout the Sharkia governorate. All samples were from chicken farms that had undergone two combinations of attenuated genotype II vaccination and standard genotype II ND inactivation. These samples were grown in ECEs before being confirmed by HA assay against the HA activity.