الفهرس 
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Abstract
The endemic HPAI H5N1 viruses in Egypt cause major losses to poultry industry due to its difficult control. So, this study aims firstly to isolate and identify the recent circulating virus for monitoring the virus evolution. The newly isolated AIV at 2016 was identified as HPAI H5N1 virus related to the classical 2.2.1.2 clade and named A/chicken/Egypt/Qal-3/2016 with accession number MF664437 on gene bank. Another aim of this study is evaluation of the commonly used inactivated AI vaccines in the Egyptian field using the invivo and invitro methods and detection of the relationship between their efficacies with the viral content and strain type. Susceptible SPF chickens were vaccinated with eight types of inactivated AI vaccines (5 batches/each) and challenged against both local HPAI classical and variant H5N1 strains at 4th WPV for invivo evaluation. It was found that all types of AI vaccines provided nearly the same protection % (ranged from 81.8% and 81.5% to 100%) and approximately the same level in viral shedding reduction (ranged from 3.3 and 1.7 log10 to 5.5 and 3.5 log10) against both local HPAI classical and variant H5N1 strains at 4th WPV respectively. On the otherhand, invitro pathway for detection of vaccine strain identity and viral content of the tested vaccines were done through separation of aqueous viral phase from oil by Iso Propyle Merestate or directly through using Triazol LS. Finally, it was concluded that The indirect assessment of protection is not considered an alternative method to the direct assessment of efficacy. Meanwhile, it can be used for direct detection of vaccine strain identification and to somewhat quantification of virus in the oil emulsion inactivated vaccine.