Location: Virus and Prion ResearchTitle: N1 neuraminidase evolution and reassortment of influenza A virus in US swine
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/28/2020
Publication Date: 1/11/2020
Citation: Hufnagel, D.E., Arendsee, Z.W., Vincent, A.L., Anderson, T.K. 2020. N1 neuraminidase evolution and reassortment of influenza A virus in US swine [abstract]. Centers of Excellence for Influenza Research and Surveillance Annual Network Meeting. Poster No. 109.
Technical Abstract: The surface proteins of influenza A virus (IAV), neuraminidase (NA) and hemagglutinin (HA), work in coordination to replicate within and transmit between hosts. Here we study the evolutionary history of swine N1 neuraminidase genes to understand if evolution of this protein coincided with evolution of the HA. We collated paired swine N1 and HA genes collected from 2010 to present and implemented a phylodynamic approach to study the evolution of both genes. These data demonstrated seasonal changes in relative diversity of the N1 genes, and the presence of five statistically supported cocirculating monophyletic clades within the last two years in US swine. Clade defining amino acids positions were identified for each of the monophyletic clades and we assessed whether diversifying selection was occurring within each clade. A time-scaled Bayesian analysis identified multiple reassortment events, resulting in novel NA-HA gene pairings, with the majority of reassortment events failing to persist in the swine population. Non-random pairing between some NA and HA clades was demonstrated, but predominant pairings changed during the study period. While HA antigens have been the focus for vaccines, neuraminidase inhibiting (NI) antibodies can also afford significant protection from infection and reduce IAV transmission. Our data provide objective information that can be used to select NA genes that are circulating in swine within and between different regions of the US and identify patterns of N1 genes paired with HA genes. Understanding N1 genetic diversity, the effect on HA diversity, and subsequent antigenic evolution and viral phenotype are critical processes in designing more efficacious vaccines and controlling IAV infection in swine, as well as risk assessment and pandemic planning for the human population.