|ABENTE, EUGENIO - Oak Ridge Institute For Science And Education (ORISE)|
|GAUGER, PHILLIP - Iowa State University|
Submitted to: Journal of General Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/7/2016
Publication Date: 1/1/2017
Citation: Abente, E.J., Kitikoon, P., Lager, K.M., Gauger, P.C., Anderson, T.K., Vincent, A.L. 2017. A highly pathogenic avian-derived influenza virus H5N1 with 2009 pandemic H1N1 internal genes demonstrates increased replication and transmission in pigs. Journal of General Virology. 98(1):18-30.
Interpretive Summary: Influenza A virus (IAV) causes respiratory disease in pigs and people, and certain IAV strains have been periodically transmitted between swine and humans in both directions. If an individual is infected with two different IAV strains, the viral genes can mix or "reassort" to generate a virus that shares properties from both parental viruses, potentially making the progeny viruses more infectious or able to avoid previous immunity from vaccination or earlier infections. Pigs may be infected with IAV from swine, human or avian sources and, thus, pose a risk for such reassorting. Here, we evaluated the ability of a highly pathogenic avian influenza (HPAI) H5N1, alone and after reassortment with human pandemic H1N1 genes, to infect swine. We observed increased replication and transmission in the reassortant H5N1 that contained H1N1 genes. These findings highlight the potential of HPAI viruses to incorporate genes from human (or swine) viruses and become more infectious to pigs, potentially leading to the emergence of viruses that could pose significant health risks to swine and/or human populations.
Technical Abstract: This study investigated the pathogenicity and transmissibility of a reverse-genetics derived highly pathogenic avian influenza (HPAI) H5N1 influenza A virus (IAV), A/Iraq/775/06, and a reassortant virus comprised of the HA and NA from A/Iraq/775/06 and the internal genes of a 2009 pandemic H1N1, A/New York/18/2009 (2Iraq/06:6NY/09 H5N1). The parental A/Iraq/775/06 caused little to no lesions in swine, limited virus replication was observed in the upper respiratory and lower respiratory tract, and transmission was detected in 3/5 pigs. In contrast, the 2Iraq/06:6NY/09 H5N1 reassortant caused mild lung lesions, demonstrated sustained virus replication in the upper and lower respiratory tracts, and transmitted to all contacts (5/5). These studies indicate that a HPAI H5N1 reassortant with pandemic internal genes may be more successful in sustaining infection in swine. Given the relatively high incidence of human-to-swine spillover events providing genetic diversity in swine IAV, and the recent reports of HPAI H5 viruses in North America, comprehensive surveillance in swine will be critical to identify a possible emerging HPAI reassortant in mammals in North America.