Skip to main content
ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Publications at this Location » Publication #414021
Research Project: Intervention Strategies to Control Endemic and New and Emerging Influenza A Virus Infections in Swine

Location: Virus and Prion Research

Title: Detection and characterization of influenza A virus endemic circulation in suckling and nursery pigs originating from vaccinated farms in the same production system

Author
item SILVA DIAS, ALESSANDRA - Federal University Of Minas Gerais
item Baker, Amy
item BAKER, RODNEY - Iowa State University
item ZHANG, JIANQIANG - Iowa State University
item ZELLER, MICHAEL - Iowa State University
item KITIKOON, PRAVINA - Merck Animal Health
item GAUGER, PHILLIP - Iowa State University

Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2024
Publication Date: 4/18/2024
Citation: Silva Dias, A., Baker, A.L., Baker, R.B., Zhang, J., Zeller, M.A., Kitikoon, P., Gauger, P.C. 2024. Detection and characterization of influenza A virus endemic circulation in suckling and nursery pigs originating from vaccinated farms in the same production system. Viruses. https://doi.org/10.3390/v16040626.
DOI: https://doi.org/10.3390/v16040626

Interpretive Summary: Influenza A virus (IAV) vaccines have been routinely used in sows to control disease on farms. Despite that, virus is still detected circulating in suckling and nursery pigs, allowing its dissemination within and between farms. In this study, we evaluated the presence of IAV in suckling and nursery piglets from IAV- vaccinated sows with history of influenza infection. Eight nasal swab collections were obtained from 135 two-week-old suckling piglets from four farms every other week from March to September 2013. Oral fluid samples were collected from the same group of nursery piglets. Influenza virus was detected in approximately 1.64% and 31% of nasal swabs and oral fluids, respectively. An H1N2 was detected most often with sporadic detection of H1N1 and H3N2. Whole genome sequences of IAV isolated from suckling piglets revealed an H1N2 circulating in this age, and a similar H1N2 was detected in the downstream nursery. These data demonstrate the low frequency of IAV detection in suckling piglets and downstream nursery from farms with endemic infections in spite of using farm-specific IAV vaccines in sows.

Technical Abstract: Inactivated influenza A virus (IAV) vaccines help reduce clinical disease in suckling piglets although endemic infections still exist. The objective of this study was to evaluate detection of IAV in suckling and nursery piglets from IAV-vaccinated sows from farms with endemic IAV infections. Eight nasal swab collections were obtained from 135 two-week-old suckling piglets from four farms every other week from March to September 2013. Oral fluid samples were collected from the same group of nursery piglets. IAV RNA was detected in 1.64% and 31.01% of individual nasal swabs and oral fluids, respectively. An H1N2 was detected most often with sporadic detection of H1N1 and H3N2. Whole genome sequences of IAV isolated from suckling piglets revealed an H1 hemagglutinin (HA) from the 1B.2.2.2 clade and N2 neuraminidase (NA) from the 2002A clade. The internal gene constellation of the endemic H1N2 was TTTTPT with a pandemic lineage matrix. The HA gene had 97.59% and 97.52% nucleotide and amino acid identities, respectively, to the H1 1B.2.2.2 used in the farm-specific vaccine. A similar H1 1B.2.2.2 was detected in the downstream nursery. These data demonstrate the low frequency of IAV detection in suckling piglets and downstream nursery from farms with endemic infections in spite of using farm-specific IAV vaccines in sows.