Has Epizootic Become Enzootic? Evidence for a Fundamental Change in the Infection Dynamics of Highly Pathogenic Avian Influenza in Europe, 2021

Pohlmann, Anne; King, Jacqueline; Fusaro, Alice; Zecchin, Bianca; Banyard, Ashley C.; Brown, Ian H.; Byrne, Alexander M. P.; Beerens, Nancy; Liang, Yuan; Heutink, René; Harders, Frank; James, Joe; Reid, Scott M.; Hansen, Rowena; Lewis, Nicola S.; Hjulsager, Charlotte Kristiane; Larsen, Lars Erik; Zohari, Siamak; Anderson, Kristofer; Bröjer, Caroline; Nagy, Alexander; Savić, Vladimir; Borm, Steven Van; Steensels, Mieke; Briand, François-Xavier; Świętoń, Edyta; Śmietanka, Krzysztof; Grund, Christian; Beer, Martin; Harder, Timm C.

doi:10.1128/mbio.00609-22

Cited by 96 publications

(145 citation statements)

References 21 publications

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“…The 2014-2015 viruses also reassorted soon after detection on the continent, but this reassortment was not associated with changes in mammalian pathogenicity 22 . The recently prevalent 2.3.4.4b viruses are also changing the dynamics of disease in Europe, with the potential for transition from epizootic to enzootic status 23 . Our data highlight how quickly things can change in a natural system, and the potential for further A(H5Nx) reassortment and phenotypic diversi cation will only increase as the unprecedented global distribution of these viruses broadens.…”

Section: Full Textmentioning

confidence: 99%

Rapid evolution of A(H5N1) influenza viruses after intercontinental spread to North America

Kandeil

Patton

et al. 2022

Preprint

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Highly pathogenic avian influenza A(H5N1) viruses of clade 2.3.4.4b underwent an explosive geographic expansion in 2021, with the viruses being detected in wild birds and domestic poultry across Asia, Europe, and Africa. In 2022, viruses of this clade were detected in North America, signifying further intercontinental spread. Here, we show that the western movement of clade 2.3.4.4b was quickly followed by reassortment with local circulating viruses, resulting in the acquisition of novel polymerase gene cassettes. These reassortant A(H5N1) viruses are genotypically and phenotypically diverse, with many causing severe disease with dramatic neurologic involvement, in mammals. The proclivity of the current A(H5N1) 2.3.4.4b virus lineage to reassort and target the central nervous system warrants concerted planning to combat the spread and evolution of the virus within the continent and to mitigate the impact of a potential influenza pandemic that could originate from similar A(H5N1) reassortants.

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Section: Full Textmentioning

confidence: 99%

Rapid evolution of A(H5N1) influenza viruses after intercontinental spread to North America

Kandeil

Patton

et al. 2022

Preprint

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“…Outbreaks of H5N8 HPAIV were, in the Far East, once terminated in spring 2021 but continuously reported in European poultry and wild birds until summer 2021 [ 7 ]. Moreover, infections with H5N1 HPAIVs, which could be generated as reassortment between H5N8 HPAIVs circulating in Europe and low-pathogenicity avian influenza viruses circulating locally, have been dominant in European countries since late spring 2021, contrary to the decrease of the reported cases of H5N8 HPAIV infections [ 8 ]. It was confirmed that two types of H5 viruses with different hemagglutinin (HA) in the genetic pool were already circulating in autumn 2021; one had been continuously present with genetic drift among the European bird population since autumn 2020, and the other, which originated in African countries but could be widely spread throughout European countries [ 8 ] had been detected since October 2021.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, infections with H5N1 HPAIVs, which could be generated as reassortment between H5N8 HPAIVs circulating in Europe and low-pathogenicity avian influenza viruses circulating locally, have been dominant in European countries since late spring 2021, contrary to the decrease of the reported cases of H5N8 HPAIV infections [ 8 ]. It was confirmed that two types of H5 viruses with different hemagglutinin (HA) in the genetic pool were already circulating in autumn 2021; one had been continuously present with genetic drift among the European bird population since autumn 2020, and the other, which originated in African countries but could be widely spread throughout European countries [ 8 ] had been detected since October 2021. Under such a circumstance, many gene-reassorted viruses, including H5N1, were generated, and dominant H5N1 reassorted viruses were further transferred from Europe to African, North American, or Asian countries in winter 2021–2022 [ 9 , 10 , 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

Detection of New H5N1 High Pathogenicity Avian Influenza Viruses in Winter 2021–2022 in the Far East, Which Are Genetically Close to Those in Europe

Isoda

Onuma

Hiono

et al. 2022

Viruses

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Many high pathogenicity avian influenza (HPAI) cases in wild birds due to H5N1 HPAI virus (HPAIV) infection were reported in northern Japan in the winter of 2021–2022. To investigate the epidemiology of HPAIVs brought to Japan from surrounding areas, a genetic analysis of H5 HPAIVs isolated in northern Japan was performed, and the pathogenicity of the HPAIV in chickens was assessed by experimental infection. Based on the genetic analysis of the hemagglutinin gene, pathogenic viruses detected in northern Japan as well as one in Sakhalin, the eastern part of Russia, were classified into the same subgroup as viruses prevalent in Europe in the same season but distinct from those circulating in Asia in winter 2020–2021. High identities of all eight segment sequences of A/crow/Hokkaido/0103B065/2022 (H5N1) (Crow/Hok), the representative isolates in northern Japan in 2022, to European isolates in the same season could also certify the unlikeliness of causing gene reassortment between H5 HPAIVs and viruses locally circulating in Asia. According to intranasal challenge results in six-week-old chickens, 50% of the chicken-lethal dose of Crow/Hok was calculated as 104.5 times of the 50% egg-infectious dose. These results demonstrated that the currently prevalent H5 HPAIVs could spread widely from certain origins throughout the Eurasian continent, including Europe and the Far East, and implied a possibility that contagious viruses are gathered in lakes in the northern territory via bird migration. Active monitoring of wild birds at the global level is essential to estimate the geographical source and spread dynamics of HPAIVs.

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“…The map in Figure 4 shows the geographical distribution of all H5N1 genotypes identified in the Czech Republic during the 2021/2022 season. The index case, ID 18520/21, is the only known representative of the resident B1 lineage among the detected viruses [10]. This finding was followed by an outbreak of H5N1 LPAI in commercial geese with close phylogeny to other European H5N1 viruses of low pathogenicity found mainly in Italy.…”

Section: Resultsmentioning

confidence: 91%

“…Taken together, the data suggests that the H5N1 HPAI has circulated at the background level throughout the entire period of dominance of the A/ck/Iq/1/2020like H5N8 strains. Moreover, one subclade apparently persisted during the summer in the wild bird population in northern Europe [9,10]. Genotyping of the H5N1 strains collected from 2020/2021 indicated the wide distribution of the original A/ew/NL/2020-like genotype constellation, with reassortants having been observed since the end of September 2021 [11].…”

Section: Introductionmentioning

confidence: 99%

Genotype Diversity, Wild Bird-to-Poultry Transmissions, and Farm-to-Farm Carryover during the Spread of the Highly Pathogenic Avian Influenza H5N1 in the Czech Republic in 2021/2022

Nagy¹,

Stará²,

Černíková³

et al. 2022

Preprint

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In 2021/2022, the re-emergence of highly pathogenic avian influenza (HPAI) occurred in Europe. The outbreak was seeded from two sources, resident and reintroduced viruses, which is unprecedented in the recorded history of avian influenza. The dominating subtype was H5N1, representing a reversion to the original A/goose/Guangdong/1/1996-like subtype combination. In this study, we present a whole genome sequence and a phylogenetic analysis of 57 H5N1 HPAI and two low pathogenic avian influenza (LPAI) H5N1 strains collected in the Czech Republic during 2021/2022. Phylogenetic analysis revealed close relationships between H5N1 genomes from poultry and wild birds and secondary transmission in commercial geese. The genotyping showed considerable genetic heterogeneity among Czech H5N1 viruses with six different HPAI genotypes, three of which were apparently unique. In addition, second-order reassortment relationships were observed with the direct involvement of co-circulating H5N1 LPAI strains. The genetic distance between Czech H5N1 HPAI and the closest LPAI segments available in the database illustrates the profound gaps in our knowledge of circulating LPAI strains. The changing dynamics of HPAI in the wild may increase the likelihood of future HPAI outbreaks and present new challenges in poultry management, biosecurity, and surveillance.

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Has Epizootic Become Enzootic? Evidence for a Fundamental Change in the Infection Dynamics of Highly Pathogenic Avian Influenza in Europe, 2021

Cited by 96 publications

References 21 publications

Rapid evolution of A(H5N1) influenza viruses after intercontinental spread to North America

Rapid evolution of A(H5N1) influenza viruses after intercontinental spread to North America

Detection of New H5N1 High Pathogenicity Avian Influenza Viruses in Winter 2021–2022 in the Far East, Which Are Genetically Close to Those in Europe

Genotype Diversity, Wild Bird-to-Poultry Transmissions, and Farm-to-Farm Carryover during the Spread of the Highly Pathogenic Avian Influenza H5N1 in the Czech Republic in 2021/2022

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