Continuous evolution of H10N8 influenza viruses in chickens and molecular determinants for their infectivity in mammals

Dr Zhu, Huachen   (Principal Investigator (PI))

Professor Guan Yi   (Co-Investigator)

Dr Lam Tsan Yuk   (Co-Investigator)

36

2015-10-01

1145430

Continuous evolution of H10N8 influenza viruses in chickens and molecular determinants for their infectivity in mammals

adaptation, interspecies transmission, mammalian infectivity, pandemic preparedness, reassortant variant

Virology

Biology and Medicine (M)

17118515

General Research Fund (GRF)

2015

Completed

1 To investigate the general infectivity of aquatic avian H10 viruses in chickens. H10 viruses from migratory waterfowl have been repeatedly introduced to domestic ducks. However, only a single introduction to chickens was observed across six provinces in southern China in our surveillance network over the past 12 years (Table 1, unpublished). Evaluation of the general infectivity of aquatic avian H10 viruses in chickens will help delineate the host range restriction of this subtype. 2 To investigate the general infectivity of aquatic bird H10 viruses in mammals. H10 is one of the few subtypes that can directly infect humans or other mammals without prior adaptation in aberrant hosts [6-12]. Viruses isolated in the past decades through our surveillance network show the genetic diversity of H10 viruses in the AIV gene pool (Table 2, unpublished). Whether the H10 viruses are generally infectious to mammals, or only specific strains are, needs to be investigated. 3 To compare the mammalian infectivity of different chicken reassortant variants and investigate if the internal genes from the enzootic H9N2 virus lineage contribute to mammalian infectivity. After the H10N8 virus was introduced into chickens, reassortments between gene pool-like and enzootic H9N2 viruses were observed (Ma et al, submitted). Among these variants some acquired human infectivity leading to three human cases [8, 13]. Phenotypic differences in the mammalian models of infection will help to identify the genetic determinants associated with their infectivity. 4 To evaluate the changes of mammalian infectivity as the H10 virus continues to evolve in chickens. Since the emergence of the novel H10N8 reassortants, H10 viruses appear to be becoming established in chickens and are continuing to evolve in poultry, leading to the accumulation of amino acid changes and further reassortment to obtain an N6 gene. Studies of these altered viruses will determine whether the infectivity of the viruses for mammals has changed.