Location: Virus and Prion ResearchTitle: Antigenic distance of North American swine influenza A virus (H3N2) and human seasonal vaccine strains as an indication of risk to human populations
|SOUZA, CARINE - OAK RIDGE INSTITUTE FOR SCIENCE AND EDUCATION (ORISE)|
|VENKATESH, DIVYA - ROYAL VETERINARY COLLEGE|
|CHANG, JENNIFER - OAK RIDGE INSTITUTE FOR SCIENCE AND EDUCATION (ORISE)|
|LEWIS, NICOLA - ROYAL VETERINARY COLLEGE|
|DETMER, SUSAN - UNIVERSITY OF SASKATCHEWAN|
|MENA, IGNACIO - THE ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI|
|CULHANE, MARIE - UNIVERSITY OF MINNESOTA|
|NELSON, MARTHA - NATIONAL INSTITUTES OF HEALTH (NIH)|
|GARCIA-SASTRE, ADOLFO - THE ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/17/2019
Publication Date: 6/26/2019
Citation: Souza, C.K., Venkatesh, D., Anderson, T.K., Chang, J., Lewis, N.S., Detmer, S.E., Mena, I., Culhane, M., Nelson, M., Garcia-Sastre, A., Vincent, A.L. 2019. Antigenic distance of North American swine influenza A virus (H3N2) and human seasonal vaccine strains as an indication of risk to human populations. CEIRS Annual Network Meeting [abstract]. p. none assigned.
Technical Abstract: Human-to-swine interspecies influenza A virus (IAV) transmission events have repeatedly occurred, some leading to sustained transmission and increased IAV diversity in pig populations. Swine H3N2 have the potential to be introduced back into humans if they have substantially drifted from current human seasonal strains. In the 1990s, an H3N2 human-to-swine introduction occurred in the US and evolved into a stable lineage (3.1990.4) that spread to Canada and Mexico. A separate introduction occurred in Mexico (3.1990.1). In the 2010s, 2 H3N2 human-to-swine spillovers were detected in the US (3.2010.1 and 3.2010.2), with the 3.2010.1 becoming the predominant H3 lineage in the US pig population. Both 3.1990.4 and 3.2010.1 swine lineages have been associated with variant H3N2 cases, highlighting a public health concern. We quantified antigenic distances using a panel of monovalent anti-sera raised in pigs against human vaccine strains (1973 -2014) and contemporary North American swine strains in hemagglutination inhibition (HI) assays. Antigenic distances between viruses were calculated in antigenic units (AU), in which 1 AU is equivalent to a 2-fold loss in HI cross-reactivity. North American 3.1990.4 swine strains retained closest antigenic distance to human vaccine strains from the decade of incursion: for example, A/Beijing/32/92 was most similar to US (1.0 -3.3AU), Mexico (1.1 -4.3AU), and Canada (2.7 -2.9AU) swine H3N2. Mexico 3.1990.1 (2.2-2.5AU) and some of the Canadian 3.1990.4 (1.6-3.4AU) were more similar to A/Wuhan/359/95 vaccine strain. All 3.1990.4 strains were at least 5AU from the recent human vaccine strains. In contrast, 3.2010.1 and 3.2010.2, had greatest antigenic distance from human vaccine strains prior to 2007 (>5.0 AU), and a closer relationship to the A/Victoria/361/11 human vaccine strain (1.7-4.4AU). HI assays with human sera will provide an assessment of human population immunity and quantify the pandemic potential of these swine H3N2 viruses.