Abstract Title
Comparison of dominant clade 2.3.4.4b high pathogenicity avian influenza viruses (HPAIV) H5N1 genotypes in avian species following spill over into terrestrial carnivores
Abstract
H5Nx clade 2.3.4.4b high-pathogenicity avian influenza virus (HPAIV) has decimated avian populations globally since autumn 2020. During this epizootic, multiple H5Nx genotypes were co-circulating in the UK and Europe. The increased reassortment between circulating strains led to the emergence of multiple defined H5N1 genotypes. Several became dominant, including AB and BB. Further, infection pressure from wild bird mortality events led to spill-over detections of H5N1 in predatory terrestrial carnivores. These observations highlighted the risk of mammalian adaptation of the H5N1 viruses and the potential for increased risk to human populations, including concerns whether viruses with mammalian adaptations might reinfect avian species via carrion feeders.
To investigate this possibility, a series of studies have been undertaken comparing infection dynamics of different genotypes in avian hosts, including assessing whether infection of avian species with a virus containing a key mammalian adaptation marker impacts on avian infection and whether that marker is sustained in the avian host.
Variation in transmission was observed both between genotypes and hosts. Ducks consistently demonstrated increased environmental contamination and more efficient transmission to naïve in-contact ducks. Genotype BB showed the highest level of transmission in chickens among the 2020-2022 H5Nx viruses assessed. For both chickens and ducks infected with AB genotype containing the PB2 K627 mutation, the polymorphism was maintained in excreted virus from both directly infected and in contact birds. Assessment of the presence of this mutation across tissues harvested at post-mortem as well as in excreted material will be discussed.
To investigate this possibility, a series of studies have been undertaken comparing infection dynamics of different genotypes in avian hosts, including assessing whether infection of avian species with a virus containing a key mammalian adaptation marker impacts on avian infection and whether that marker is sustained in the avian host.
Variation in transmission was observed both between genotypes and hosts. Ducks consistently demonstrated increased environmental contamination and more efficient transmission to naïve in-contact ducks. Genotype BB showed the highest level of transmission in chickens among the 2020-2022 H5Nx viruses assessed. For both chickens and ducks infected with AB genotype containing the PB2 K627 mutation, the polymorphism was maintained in excreted virus from both directly infected and in contact birds. Assessment of the presence of this mutation across tissues harvested at post-mortem as well as in excreted material will be discussed.
Co-Author(s)
Elizabeth Billington1, Sofia Riccio1, Kajal Ralh1, Jessica Quantrill2,3, Caroline Warren1, Kelly Roper1, Benjamin Mollett1, Dilhani de Silva1, Jacob Peers-Dent1, Saumya Thomas1, Cecilia Di Genova1, Simon Johnson1, Marek J. Slomka1, Wendy Barclay2, Thomas Peacock2,3, Ashley C. Banyard1, 3@ and Joe James1, 2, 3
1Department of Virology, Animal and Plant Health Agency (APHA-Weybridge), Woodham Lane, Addlestone, Surrey KT15 3NB, UK
2Imperial College London
3The Pirbright Institute, Ash Road, Pirbright, Woking, GU24 0NF, UK
Abstract Category
Avian influenza in mammals, pandemic preparedness, and one health