Genetic characteristics, pathobiological features and control strategies of the newly emerging avian influenza H5N8 virus / Yassmin Mohamed Moatasim Mohamed Fatouh ; Supervised Elsayed Tarek Abdelsalam , Mohamed Ahmed Ali , Maha Alkhazindar

Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Biotechnology

Introduction: Since 2006, HPAIV H5N1 was circulating in Egyptian poultry, and became endemic in 2008. LPAIV H9N2 started cocirculating with H5N1 in Egyptian farms in 2011, and both continued to cocirculate till recently. In 2016, HPAIV H5N8 was first detected in Egypt in wild birds and then emerged in Egyptian poultry, cocirculating with the previous 2 influenza subtypes. little is known about the virological and pathological features of the newly emerging HPAIV H5N8 in Egypt. Cocirculation of the 3 viruses in Egyptian farms caused massive economic losses and health burdens. Also, this cocirculation can cause the genetic shuffling between these viruses in the infected host and production of new reassortant viruses with unknown characteristics. Surveillance and virological characterization are important to assess the zoonotic potential, and vaccination strategies should be improved to induce domestic poultry protection, as the genetic mismatch of vaccine seed strains in commercial products and circulating AIVs could led to vaccination failure and rapid evolution of H5N8 virus. Thus, in the first part in this thesis, virological and pathogenic characteristics of first introduction wave of HPAI H5N8 viruses.In the second part of thesis, we studied the impact of individual viral gene segments from influenza A/H5N8 virus on the protective efficacy of inactivated subtype-specific influenza vaccine. In the third part, genetic and antigenic characterizations of HPAI H5N8 viruses in Egypt 2016-2020 were studied

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