Outbreaks among Wild Birds and Domestic Poultry Caused by Reassorted Influenza A(H5N8) Clade 2.3.4.4 Viruses, Germany, 2016

Pohlmann, Anne; Starick, Elke; Harder, Timm C.; Grund, Christian; Höper, Dirk W.; Globig, Anja; Staubach, Christoph; Dietze, Klaas; Strebelow, Günter; Ulrich, Reiner; Schinköthe, Jan; Teifke, Jens Peter; Conraths, Franz Josef; Mettenleiter, Thomas C.; Beer, Martin

doi:10.3201/eid2304.161949

Cited by 95 publications

(97 citation statements)

References 7 publications

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“…Although Croatian H5N8 index case virus Swn70-H5N8 is genetically closely related to the isolates from Russia-Mongolia border, the full genome sequence of this virus have shown that it clearly differs in two gene segments; polymerase basic (PB) 2 and NP. Similarly, German 2016 H5N8 virus could be clearly distinguished from the isolates from Russia-Mongolia in PA and NP segments (POHLMANN et al, 2017). According to phylogenetic tree topologies and the tree positions of these two viruses from Croatia and Germany as well as other recent H5N8 viruses (Figs 2-9) it is evident that several novel H5N8 reassortant viruses of clade 2.3.4.4 group B emerged and spread in wild birds and poultry within Asia and Europe in late 2016 and early 2017.…”

Section: Resultsmentioning

confidence: 80%

“…Discussion HPAI virus subtype H5N8 was first confirmed in dead mute swans in east Croatia in late October 2016 and the epidemic spread within following winter months among wild birds throughout inland Croatia. The virus is closely related to novel reassortant clade 2.3.4.4 group B H5N8 virus which was detected in wild migratory birds at the Qinghai Lake, China and Russia-Mongolia border already in spring 2016 (LEE et al, 2017, LI et al, 2017, followed by detection in autumn in poultry in European Russia (MARCHENKO et al, 2017) and wild birds and poultry in other European countries (POHLMANN et al, 2017). This dissemination of the virus from Asia to Europe was attributed to aquatic bird migration, as was the case with H5N8 clade 2.3.4.4 group A virus when it spread worldwide in 2014-2015 by long-distance migratory birds (GLOBAL CONSORTIUM FOR H5N8, 2016).…”

Section: Resultsmentioning

confidence: 93%

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Novel reassortant clade 2.3.4.4 avian influenza A(H5N5) virus in wild birds and poultry, Croatia, 2016-2017

Savić

2017

Vet. arhiv

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Highly pathogenic avian influenza (HPAI) causes flock mortality as high as 100% in susceptible poultry species but it also poses a threat for humans, particularly viruses of A/goose/Guangdong/96-like (GD/96) lineage. The emergence of novel HPAI viruses in migratory birds is of concern because of the potential for virus spread during migration. In late 2016, novel GD/96 reassortant clade 2.3.4.4 group B avian influenza H5N5 virus was detected in wild birds and domestic poultry in Croatia, concurrently with numerous detections of H5N8 virus of the same clade and group. Sequencing of the full genome of the H5N8 index case isolate (October 2016) and of all three H5N5 isolates (December 2016 -March 2017) has shown that the novel H5N5 reassortant virus most likely emerged as a result of complex reassortment process in Asia from HPAI H5N8 viruses after the later viruses have became established in wild bird population. Concurrent findings of both, H5N5 and H5N8 viruses, at the same locations in Croatia indicate that the H5N5 reassortant virus was introduced from Asia as a subpopulation of H5N8 viruses by the same wild bird flyways. Although the novel H5N5 reassortant virus possesses haemagglutinin of the GD/96 lineage, the virus genome has typical avian virus traits. Apart from mutations T215A in M1 protein and P42S in NS1 protein which are associated to increased virulence in mice, none of the mutations related to increased affinity to human-type (α-2,6) receptors and mammalian host adaptation were found. Nevertheless, the virus poses a serious threat to the poultry industry since high pathogenicity for gallinaceous birds was confirmed by high intravenous pathogenicity index (2.87).

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Section: Resultsmentioning

confidence: 80%

Section: Resultsmentioning

confidence: 93%

Novel reassortant clade 2.3.4.4 avian influenza A(H5N5) virus in wild birds and poultry, Croatia, 2016-2017

Savić

2017

Vet. arhiv

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“…These strains could be clearly distinguished from the first reported strains as they belonged to different genotypes involving several gene segments including another NA subtype (N5). Phylogenetic analyses indicated that multiple independent incursions of HPAIV into Germany had occurred more or less at the same time (15). …”

Section: Resultsmentioning

confidence: 99%

Highly Pathogenic Avian Influenza H5N8 Clade 2.3.4.4b in Germany in 2016/2017

et al. 2018

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Here, we report on the occurrence of highly pathogenic avian influenza (HPAI) H5Nx clade 2.3.4.4b in Germany. Between November 8, 2016, and September 30, 2017, more than 1,150 cases of HPAI H5Nx clade 2.3.4.4b in wild birds and 107 outbreaks in birds kept in captivity (92 poultry holdings and 15 zoos/animal parks) were reported in Germany. This HPAI epidemic is the most severe recorded in Germany so far. The viruses were apparently introduced by migratory birds, sparking an epidemic among wild birds across Germany with occasional incursions into poultry holdings, zoos and animal parks, which were usually rapidly detected and controlled by stamping out. HPAI viruses (mainly subtype H5N8, in a few cases also H5N5) were found in dead wild birds of at least 53 species. The affected wild birds were water birds (including gulls, storks, herons, and cormorants) and scavenging birds (birds of prey, owls, and crows). In a number of cases, substantial gaps in farm biosecurity may have eased virus entry into the holdings. In a second wave of the epidemic starting from February 2017, there was epidemiological and molecular evidence for virus transmission of the infections between commercial turkey holdings in an area of high poultry density, which caused approximately 25% of the total number of outbreaks in poultry. Biosecurity measures in poultry holdings should be adapted. This includes, inter alia, wearing of stable-specific protective clothing and footwear, cleaning, and disinfection of equipment that has been in contact with birds and prevention of contacts between poultry and wild water birds.

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“…Cells were overlaid with serum-free medium and incubated at 37°C in 5% CO 2 in the absence of trypsin. After 1,8,24,48, and 72 h, the supernatant was harvested and stored at Ϫ80°C. Removal of the cell debris from the thawed suspension was performed by centrifugation at 800 ϫ g for 5 min.…”

Section: Methodsmentioning

confidence: 99%

“…Immunohistochemistry was performed on serial sections to detect influenza A virus antigen using the avidin-biotin-peroxidase complex method (Vectastain PK 6100; Vector Laboratories, Burlingame, CA, USA) with citric buffer (10 mM, pH 6.0) pretreatment, a polyclonal rabbit anti-influenza A virus FPV/Rostock/34 nucleoprotein antiserum (diluted 1:750) (47), 3-amino-9-ethylcarbazol as the chromogen (Agilent Technologies, Santa Clara, CA, USA), and hematoxylin counterstain. The specificity of the immunohistochemical reaction was confirmed by the use of negative tissues from noninfected chicken and ferret archival diagnostic cases, as well as validated positive avian tissues from the recent H5N8 outbreak (48). Serial sections of the negative controls were treated with rabbit serum instead of the primary polyclonal antiserum.…”

Section: Methodsmentioning

confidence: 99%

Natural Reassortants of Potentially Zoonotic Avian Influenza Viruses H5N1 and H9N2 from Egypt Display Distinct Pathogenic Phenotypes in Experimentally Infected Chickens and Ferrets

Naguib

Ulrich

Kasbohm

et al. 2017

J Virol

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The cocirculation of zoonotic highly pathogenic avian influenza virus (HPAIV) of subtype H5N1 and avian influenza virus (AIV) of subtype H9N2 among poultry in Egypt for at least 6 years should render that country a hypothetical hot spot for the emergence of reassortant, phenotypically altered viruses, yet no reassortants have been detected in Egypt. The present investigations proved that reassortants of the Egyptian H5N1 clade 2.2.1.2 virus and H9N2 virus of the G1-B lineage can be generated by coamplification in embryonated chicken eggs. Reassortants were restricted to the H5N1 subtype and acquired between two and all six of the internal segments of the H9N2 virus. Five selected plaque-purified reassortant clones expressed a broad phenotypic spectrum both in vitro and in vivo. Two groups of reassortants were characterized to have retarded growth characteristics in vitro compared to the H5N1 parent virus. One clone provoked reduced mortality in inoculated chickens, although the characteristics of a highly pathogenic phenotype were retained. Enhanced zoonotic properties were not predicted for any of these clones, and this prediction was confirmed by ferret inoculation experiments: neither the H5N1 parent virus nor two selected clones induced severe clinical symptoms or were transmitted to sentinel ferrets by contact. While the emergence of reassortants of Egyptian HPAIV of subtype H5N1 with internal gene segments of cocirculating H9N2 viruses is possible in principle, the spread of such viruses is expected to be governed by their fitness to outcompete the parental viruses in the field. The eventual spread of attenuated phenotypes, however, would negatively impact syndrome surveillance on poultry farms and might foster enzootic virus circulation.IMPORTANCE Despite almost 6 years of the continuous cocirculation of highly pathogenic avian influenza virus H5N1 and avian influenza virus H9N2 in poultry in Egypt, no reassortants of the two subtypes have been reported. Here, the principal compatibility of the two subtypes is shown by forcing the reassortment between copassaged H5N1 und H9N2 viruses in embryonated chicken eggs. The resulting reassortant viruses displayed a wide range of pathogenicity including attenuated phenotypes in chickens, but did not show enhanced zoonotic propensities in the ferret model.

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Outbreaks among Wild Birds and Domestic Poultry Caused by Reassorted Influenza A(H5N8) Clade 2.3.4.4 Viruses, Germany, 2016

Cited by 95 publications

References 7 publications

Novel reassortant clade 2.3.4.4 avian influenza A(H5N5) virus in wild birds and poultry, Croatia, 2016-2017

Novel reassortant clade 2.3.4.4 avian influenza A(H5N5) virus in wild birds and poultry, Croatia, 2016-2017

Highly Pathogenic Avian Influenza H5N8 Clade 2.3.4.4b in Germany in 2016/2017

Natural Reassortants of Potentially Zoonotic Avian Influenza Viruses H5N1 and H9N2 from Egypt Display Distinct Pathogenic Phenotypes in Experimentally Infected Chickens and Ferrets

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