Emergence of H3N2pM‐like and novel reassortant H3N1 swine viruses possessing segments derived from the A (H1N1)pdm09 influenza virus, Korea

Abstract

BackgroundHuman‐to‐swine transmission of the pandemic H1N1 2009 [A(H1N1)pdm09] virus in pig populations resulted in reassortment events with endemic swine influenza viruses worldwide.ObjectiveWe investigated whether A(H1N1)pdm09‐derived reassortant viruses are present in South Korea and sought to determine the pathogenic potential of the novel swine viruses.MethodsPig lung tissues were collected from commercially slaughtered pigs. Isolated swine influenza viruses were genetically analyzed and characterized in vitro and in vivo.ResultsWe identified reassortant H3N2 (H3N2pM‐like) and H3N1 swine viruses containing A(H1N1)pdm09‐like segments in Korean pigs that are genetically closely related to strains recently detected in pigs and humans in North America. Although the H3N2pM‐like and novel H3N1 reassortants demonstrated efficient replication in mice and ferrets, all the H3N1 strains exhibited growth advantage over the representative H3N2pM‐like virus in human airway cells. Interestingly, A/swine/Korea/CY02‐07/2012(H3N1) and A/swine/Korea/CY03‐13/2012(H3N1) reassortants were more readily transmitted to respiratory‐droplet‐contact ferrets compared with the H3N2pM‐like (A/swine/Korea/CY02‐10/2012) isolate. Furthermore, serologic evaluation showed poor antigenicity to contemporary reference human seasonal H3N2 vaccine strains.ConclusionsWe report here for the first time the isolation of H3N2pM‐like viruses outside North America and of novel reassortant swine H3N1 viruses with A(H1N1)pdm09‐derived genes. Apart from further complicating the genetic diversity of influenza A viruses circulating in domestic pigs, our data also indicate that these strains could potentially pose threat to public health asserting the need for continuous virus monitoring in these ecologically important hosts.

Detection of Novel Reassortant Influenza A (H3N2) and H1N1 2009 Pandemic Viruses in Swine in Hanoi, Vietnam

“…The deduced PB2, PB1 and NS sequences were closely related to those derived from American TR swine influenza viruses (PB2: A/swine/North Carolina/02023/2008, Sequence identity: 96%; PB1: A/swine/Manitoba/01093/2006, Sequence identity: 98% and NS: A/swine/Manitoba/02185/2008; Sequence identity: 97%), whereas the deduced PA, NP and M gene sequences were all similar to those derived from A(H1N1)pdm09 lineage. Thus, the gene constellation of swine H3N2 viruses of this study is genetically distinct from H3N2 reassortants isolated from Korea (Pascua et al., ) and Vietnam (Ngo et al., ), indicating that these H3N2 are novel reassortants. All the H3N2 viruses previously isolated in Vietnam came from one study in Southern Vietnam, and the haemagglutinin and neuraminidase originated from a H3N2 human virus while the internal genes were of an American TR lineage.…”

Comparison of the pathogenic potential of highly pathogenic avian influenza (HPAI) H5N6, and H5N8 viruses isolated in South Korea during the 2016–2017 winter season

“…Virus sequences were prepared and analyzed as previously described 38 . Briefly, gene sequences of Em/W541(H5N6) and CT/W555(H5N8) were obtained by Cosmo Genetech (Seoul, Korea) using an ABI 3730XL DNA sequencer (Applied Biosystems, Foster City, CA, USA).…”

Scientific opinion on the possible risks posed by the influenza A (H3N2v) virus for animal health and its potential spread and implications for animal and human health

“…Most recently, reassortant viruses very similar to H3N2pM have been isolated from healthy slaughter pigs in Korea (Pascua et al 2013). Both the North American TR H3N2 and A(H1N1)pdm09 have also been recovered from pigs in Korea and it is therefore not possible to conclude whether the H3N2pM has been generated locally or whether it was brought in by import of live pigs.…”