Abstract Title
Investigation of the emergence pathways of EA-2021-AB and EA-2022-BB A(H5N1) avian influenza genotypes
Abstract
Two high pathogenicity avian influenza genotypes; (EA-2021-)AB and (EA-2022-)BB dominated in Europe during 2022-2023, causing mass mortality events in wild birds and poultry. These genotypes differ in composition and represent distinct emergence events. To understand the emergence of these genotypes, a custom BLAST database, using all sequences available in the GISAID EpiFlu platform, was queried using representative AB and BB genotype sequences. Metadata, including (host order, country and subtype) was also collated.
TreeTime mugration models showed an effect of host order on the composition of both genotypes. Anseriformes contributed the NP, PB2 and PA to the AB genotype, while HA, MP, PB1 and NS were contributed by Anseriformes and Galliformes. For the BB genotype, Charadriiformes contributed to NS and NP, while Charadriiformes and Anseriformes contributed to PB2 and PA. HA and NA were contributed by Charadriiformes, Pelecaniformes, Anseriformes and Galliformes.
Both AB and BB genotypes mugration models found individual segments originated from previous different subtypes. For example, in the AB genotype, PB1 originated from H7N3 and H5N8 viruses, while the HA originated from H5N8. In the BB genotype, HA and PB1 originated from previous H5N8 and H5N1, while NA originated from H1N1 and H6N1. Also, as expected two genotypes show close relatedness to other contemporary H5N1 genotypes circulating in Europe from ~2020-2023. These findings demonstrate distinct evolutionary pathways for the emergence of two H5N1 genotypes that were prevalent in Europe and provides further insight into HPAI evolution.
TreeTime mugration models showed an effect of host order on the composition of both genotypes. Anseriformes contributed the NP, PB2 and PA to the AB genotype, while HA, MP, PB1 and NS were contributed by Anseriformes and Galliformes. For the BB genotype, Charadriiformes contributed to NS and NP, while Charadriiformes and Anseriformes contributed to PB2 and PA. HA and NA were contributed by Charadriiformes, Pelecaniformes, Anseriformes and Galliformes.
Both AB and BB genotypes mugration models found individual segments originated from previous different subtypes. For example, in the AB genotype, PB1 originated from H7N3 and H5N8 viruses, while the HA originated from H5N8. In the BB genotype, HA and PB1 originated from previous H5N8 and H5N1, while NA originated from H1N1 and H6N1. Also, as expected two genotypes show close relatedness to other contemporary H5N1 genotypes circulating in Europe from ~2020-2023. These findings demonstrate distinct evolutionary pathways for the emergence of two H5N1 genotypes that were prevalent in Europe and provides further insight into HPAI evolution.
Co-Author(s)
Dilhani de Silva-Department of Virology, Animal and Plant Health Agency, UK
Jacob Peers-Dent-Department of Virology, Animal and Plant Health Agency, UK
Ben Mollett-Department of Virology, Animal and Plant Health Agency, UK
Holly Coombes-Department of Virology, Animal and Plant Health Agency, UK
Alexander MP Byrne -The Francis Crick Institute, London, UK
Alice Fusaro-European Reference Laboratory (EURL) for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale delle Venezie, Padua, Italy
Isabella Monne -European Reference Laboratory (EURL) for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale delle Venezie, Padua, Italy
Enrico Savegnago-European Reference Laboratory (EURL) for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale delle Venezie, Padua, Italy
Bianca Zecchin -European Reference Laboratory (EURL) for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale delle Venezie, Padua, Italy
Ambra Pastori-European Reference Laboratory (EURL) for Avian Influenza and Newcastle Disease, Istituto Zooprofilattico Sperimentale delle Venezie, Padua, Italy
Joe James-Department of Virology, Animal and Plant Health Agency, UK
Ashley C Banyard -Department of Virology, Animal and Plant Health Agency, UK
Abstract Category
Notable outbreaks, field and molecular epidemiology, and surveillance in wild birds