Multiple Reassorted Viruses as Cause of Highly Pathogenic Avian Influenza A(H5N8) Virus Epidemic, the Netherlands, 2016

Abstract

In 2016, an epidemic of highly pathogenic avian influenza A virus subtype H5N8 in the Netherlands caused mass deaths among wild birds, and several commercial poultry farms and captive bird holdings were affected. We performed complete genome sequencing to study the relationship between the wild bird and poultry viruses. Phylogenetic analysis showed that the viruses are related to H5 clade 2.3.4.4 viruses detected in Russia in May 2016 but contained novel polymerase basic 2 and nucleoprotein gene segments and 2 different variants of the polymerase acidic segment. Molecular dating suggests that the reassortment events most likely occurred in wild birds in Russia or Mongolia. Furthermore, 2 genetically distinct H5N5 reassortant viruses were detected in wild birds in the Netherlands. Our study provides evidence for fast and continuing reassortment of H5 clade 2.3.4.4 viruses, which might lead to rapid changes in virus characteristics, such as pathogenicity, infectivity, transmission, and zoonotic potential.

Genetic relationship between poultry and wild bird viruses during the highly pathogenic avian influenza H5N6 epidemic in the Netherlands, 2017–2018

“…However for the H5N8 2014 group A virus, no mortality was observed in the wild bird population. We previously showed that the pathogenicity of the three viruses for galliform birds was similar, for all viruses an IVPI score of 3.0 was measured (Beerens et al., , ; Bouwstra, Heutink, et al., ). In this study, we performed an IVPI experiment using ducks.…”

“…Briefly, purified amplicons were sequenced at high coverage (average >1000 per nucleotide position) using the Nextera library preparation method and Illumina MiSeq paired‐end 150 base pairs sequencing. Quality control‐passed sequence reads were mapped using the ViralProfiler‐Workflow, an extension of the CLC Genomics Workbench (Qiagen, Germany), as previously described (Beerens et al., ). The consensus sequences generated in this study were submitted to the GISAID database.…”

“…Of these reassortant viruses, the clade 2.3.4.4 H5 viruses further evolved into four genetic groups, named A to D (Lee et al., ). Outbreaks in poultry in the Netherlands were caused by H5N8 group A viruses in 2014 (Bouwstra, Heutink, et al., ; Bouwstra, Koch, et al., ), and H5N8 group B viruses in 2016 (Beerens et al., ). In December 2017, an outbreak of HPAI H5N6 was detected on a commercial poultry farm in the Netherlands.…”

Protective Measures for Humans against Avian Influenza A(H5N8) Outbreaks in 22 European Union/European Economic Area Countries and Israel, 2016–17

“…H5N8 virus had not previously been widely seen in Europe, and the risk for bird-to-human transmission was not clear. Avian outbreaks increased in number, size, and distribution among migratory and resident birds, zoo birds, backyard farms, and poultry holdings, to a scale not previously observed for a subtype during a winter season ( 23 , 24 ). Overall, 24 of the 31 the European Union/European Economic Area (EU/EEA) countries, neighboring countries, Israel, and countries in the Middle East were facing large avian influenza outbreaks in poultry or wild birds during the study period, and there was great uncertainty about the risk for virus transmission from birds to humans ( 25 ).…”

Deaths among Wild Birds during Highly Pathogenic Avian Influenza A(H5N8) Virus Outbreak, the Netherlands

“…This time lag might be related to the limited mobility of wintering Aythya ducks, which, in contrast to Eurasian wigeons, rarely fly over land between foraging and roosting sites. Wild bird ecology might thus affect infection risk among poultry, which was further explored by researchers using network analyses of virus sequences obtained from wild birds and poultry during the same outbreak ( 14 ). …”