Highly Pathogenic Avian Influenza in Japan: Outbreaks, Control Measures, and Roles of Wild Birds

Highly pathogenic avian influenza (HPAI) causes devastating economic loss to the poultry industry and poses a significant threat to food safety and public health. In Asia, the H5N1 HPAI virus has been circulating since 1996, and human infection has occurred sporadically. Points important for preventing outbreaks are biosecurity at chicken farms, monitoring, rapid diagnosis, and eradication of the virus from farms where outbreaks occur. Vaccination for chickens is not recommended because low vaccine efficacy may allow the circulation of the virus in vaccinated flocks. Since we experienced many chicken outbreaks and many deaths of wild birds in the 2010/2011 birdwintering season in Japan, biosecurity measures at farms have been enhanced and real-time PCR has been introduced as a rapid, reliable diagnostic test at animal hygiene service centers in Japan in 2011. Since risk of the H5N1 virus being maintained in wild bird populations may be increasing, international wild bird surveillance at the residential and bird-wintering places may be more important than ever. Real-time RT-PCR (SYBR) for subtyping HA and NA genes of AI viruses is quite useful for surveillance.

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Lack of virological and serological evidence for continued circulation of highly pathogenic avian influenza H5N8 virus in wild birds in the Netherlands, 14 November 2014 to 31 January 2016

Eurosurveillance ◽

10.2807/1560-7917.es.2016.21.38.30349 ◽

2016 ◽

Vol 21 (38) ◽

Cited By ~ 18

Author(s):

Marjolein J Poen ◽

Josanne H Verhagen ◽

Ruth J Manvell ◽

Ian Brown ◽

Theo M Bestebroer ◽

...

Keyword(s):

The Netherlands ◽

Avian Influenza ◽

Wild Bird ◽

Highly Pathogenic Avian Influenza ◽

Haemagglutination Inhibition ◽

Wild Birds ◽

Antibody Detection ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

H5n8 Virus

In 2014, H5N8 clade 2.3.4.4 highly pathogenic avian influenza (HPAI) viruses of the A/Goose/Guangdong/1/1996 lineage emerged in poultry and wild birds in Asia, Europe and North America. Here, wild birds were extensively investigated in the Netherlands for HPAI H5N8 virus (real-time polymerase chain reaction targeting the matrix and H5 gene) and antibody detection (haemagglutination inhibition and virus neutralisation assays) before, during and after the first virus detection in Europe in late 2014. Between 21 February 2015 and 31 January 2016, 7,337 bird samples were tested for the virus. One HPAI H5N8 virus-infected Eurasian wigeon (Anas penelope) sampled on 25 February 2015 was detected. Serological assays were performed on 1,443 samples, including 149 collected between 2007 and 2013, 945 between 14 November 2014 and 13 May 2015, and 349 between 1 September and 31 December 2015. Antibodies specific for HPAI H5 clade 2.3.4.4 were absent in wild bird sera obtained before 2014 and present in sera collected during and after the HPAI H5N8 emergence in Europe, with antibody incidence declining after the 2014/15 winter. Our results indicate that the HPAI H5N8 virus has not continued to circulate extensively in wild bird populations since the 2014/15 winter and that independent maintenance of the virus in these populations appears unlikely.

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Local amplification of highly pathogenic avian influenza H5N8 viruses in wild birds in the Netherlands, 2016 to 2017

Eurosurveillance ◽

10.2807/1560-7917.es.2018.23.4.17-00449 ◽

2018 ◽

Vol 23 (4) ◽

Cited By ~ 22

Author(s):

Marjolein J. Poen ◽

Theo M. Bestebroer ◽

Oanh Vuong ◽

Rachel D. Scheuer ◽

Henk P. van der Jeugd ◽

...

Keyword(s):

The Netherlands ◽

Avian Influenza ◽

Wild Bird ◽

Highly Pathogenic Avian Influenza ◽

Wild Birds ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

Large Numbers ◽

Outbreak Investigations ◽

Bird Mortality

Introduction Highly pathogenic avian influenza (HPAI) viruses of subtype H5N8 were re-introduced into the Netherlands by late 2016, after detections in south-east Asia and Russia. This second H5N8 wave resulted in a large number of outbreaks in poultry farms and the deaths of large numbers of wild birds in multiple European countries. Methods: Here we report on the detection of HPAI H5N8 virus in 57 wild birds of 12 species sampled during active (32/5,167) and passive (25/36) surveillance activities, i.e. in healthy and dead animals respectively, in the Netherlands between 8 November 2016 and 31 March 2017. Moreover, we further investigate the experimental approach of wild bird serology as a contributing tool in HPAI outbreak investigations. Results: In contrast to the first H5N8 wave, local virus amplification with associated wild bird mortality has occurred in the Netherlands in 2016/17, with evidence for occasional gene exchange with low pathogenic avian influenza (LPAI) viruses. Discussion: These apparent differences between outbreaks and the continuing detections of HPAI viruses in Europe are a cause of concern. With the current circulation of zoonotic HPAI and LPAI virus strains in Asia, increased understanding of the drivers responsible for the global spread of Asian poultry viruses via wild birds is needed.

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Mutations in PB1, NP, HA, and NA Contribute to Increased Virus Fitness of H5N2 Highly Pathogenic Avian Influenza Virus Clade 2.3.4.4 in Chickens

Journal of Virology ◽

10.1128/jvi.01675-20 ◽

2020 ◽

Author(s):

Sung-Su Youk ◽

Christina M. Leyson ◽

Brittany A. Seibert ◽

Samadhan Jadhao ◽

Daniel R. Perez ◽

...

Keyword(s):

Avian Influenza ◽

Wild Bird ◽

Highly Pathogenic Avian Influenza ◽

The United States ◽

Wild Birds ◽

Highly Pathogenic ◽

Genetic Changes ◽

Evolutionary Pathway ◽

Pathogenic Avian Influenza ◽

Virus Fitness

The H5N8 highly pathogenic avian influenza (HPAI) clade 2.3.4.4 virus spread to North America by wild birds and reassorted to generate the H5N2 HPAI virus that caused the poultry outbreak in the United States in 2015. In previous studies, we showed that H5N2 viruses isolated from poultry in the later stages of the outbreak had higher infectivity and transmissibility in chickens than the wild bird index H5N2 virus. Here, we determined the genetic changes that contributed to the difference in host virus fitness by analyzing sequence data from all of the viruses detected during the H5N2 outbreak, and studying the pathogenicity of reassortant viruses generated with the index wild bird virus and a chicken virus from later in the outbreak. Viruses with the wild bird virus backbone and either PB1, NP, or the entire polymerase complex of the chicken isolate, caused higher and earlier mortality in chickens, with three mutations (PB1 E180D, M317V, and NP I109T) identified to increase polymerase activity in chicken cells. The reassortant virus with the HA and NA from the chicken virus, where mutations in functionally known gene regions were acquired as the virus circulated in turkeys (HA S141P and NA S416G) and later in chickens (HA M66I, L322Q), showed faster virus growth, bigger plaque size and enhanced heat persistence in vitro, and increased pathogenicity and transmissibility in chickens. Collectively, these findings demonstrate an evolutionary pathway in which a HPAI virus from wild birds can accumulate genetic changes to increase fitness in poultry. IMPORTANCE H5Nx highly pathogenic avian influenza (HPAI) viruses of the A/goose/Guangdong/1/96 lineage continue to circulate widely affecting both poultry and wild birds. These viruses continue to change and reassort, which affects their fitness to different avian hosts. In this study, we defined mutations associated with increased virus fitness in chickens as the clade 2.3.4.4. H5N2 HPAI virus circulated in different avian species. We identified mutations in the PB1, NP, HA, and NA virus proteins that were highly conserved in the poultry isolates and contributed to the adaptation of this virus in chickens. This knowledge is important for understanding the epidemiology of H5Nx HPAI viruses and specifically the changes related to adaptation of these viruses in poultry.

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First detection of highly pathogenic avian influenza virus in Norway

BMC Veterinary Research ◽

10.1186/s12917-021-02928-4 ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

Knut Madslien ◽

Torfinn Moldal ◽

Britt Gjerset ◽

Sveinn Gudmundsson ◽

Arne Follestad ◽

...

Keyword(s):

Avian Influenza ◽

Influenza A ◽

Highly Pathogenic Avian Influenza ◽

Wild Birds ◽

Zoonotic Potential ◽

Active Monitoring ◽

Main Hypothesis ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

Poultry Farms

Abstract Background Several outbreaks of highly pathogenic avian influenza (HPAI) caused by influenza A virus of subtype H5N8 have been reported in wild birds and poultry in Europe during autumn 2020. Norway is one of the few countries in Europe that had not previously detected HPAI virus, despite widespread active monitoring of both domestic and wild birds since 2005. Results We report detection of HPAI virus subtype H5N8 in a wild pink-footed goose (Anser brachyrhynchus), and several other geese, ducks and a gull, from south-western Norway in November and December 2020. Despite previous reports of low pathogenic avian influenza (LPAI), this constitutes the first detections of HPAI in Norway. Conclusions The mode of introduction is unclear, but a northward migration of infected geese or gulls from Denmark or the Netherlands during the autumn of 2020 is currently our main hypothesis for the introduction of HPAI to Norway. The presence of HPAI in wild birds constitutes a new, and ongoing, threat to the Norwegian poultry industry, and compliance with the improved biosecurity measures on poultry farms should therefore be ensured. [MK1]Finally, although HPAI of subtype H5N8 has been reported to have very low zoonotic potential, this is a reminder that HPAI with greater zoonotic potential in wild birds may pose a threat in the future. [MK1]Updated with a sentence emphasizing the risk HPAI pose to poultry farms, both in the Abstract and in the Conclusion-section in main text, as suggested by Reviewer 1 (#7).

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Highly Pathogenic Avian Influenza Viruses at the Wild–Domestic Bird Interface in Europe: Future Directions for Research and Surveillance

Viruses ◽

10.3390/v13020212 ◽

2021 ◽

Vol 13 (2) ◽

pp. 212

Author(s):

Josanne H. Verhagen ◽

Ron A. M. Fouchier ◽

Nicola Lewis

Keyword(s):

Avian Influenza ◽

Highly Pathogenic Avian Influenza ◽

Wild Birds ◽

Influenza Viruses ◽

Highly Pathogenic ◽

Future Directions ◽

Pathogenic Avian Influenza ◽

Domestic Bird ◽

Hpai H5n1 ◽

Host Identification

Highly pathogenic avian influenza (HPAI) outbreaks in wild birds and poultry are no longer a rare phenomenon in Europe. In the past 15 years, HPAI outbreaks—in particular those caused by H5 viruses derived from the A/Goose/Guangdong/1/1996 lineage that emerged in southeast Asia in 1996—have been occuring with increasing frequency in Europe. Between 2005 and 2020, at least ten HPAI H5 incursions were identified in Europe resulting in mass mortalities among poultry and wild birds. Until 2009, the HPAI H5 virus outbreaks in Europe were caused by HPAI H5N1 clade 2.2 viruses, while from 2014 onwards HPAI H5 clade 2.3.4.4 viruses dominated outbreaks, with abundant genetic reassortments yielding subtypes H5N1, H5N2, H5N3, H5N4, H5N5, H5N6 and H5N8. The majority of HPAI H5 virus detections in wild and domestic birds within Europe coincide with southwest/westward fall migration and large local waterbird aggregations during wintering. In this review we provide an overview of HPAI H5 virus epidemiology, ecology and evolution at the interface between poultry and wild birds based on 15 years of avian influenza virus surveillance in Europe, and assess future directions for HPAI virus research and surveillance, including the integration of whole genome sequencing, host identification and avian ecology into risk-based surveillance and analyses.

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