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ORIGINAL RESEARCH article

Front. Vet. Sci.
Sec. Veterinary Infectious Diseases
Volume 11 - 2024 | doi: 10.3389/fvets.2024.1482225

Influenza A virus shedding and reinfection during the post-weaning period in swine: longitudinal study of two nurseries

Provisionally accepted
Suzanna M. Storms Suzanna M. Storms *Antonio Leonardi-Cattolica Antonio Leonardi-Cattolica Tara Prezioso Tara Prezioso Csaba Varga Csaba Varga Leyi Wang Leyi Wang JAMES LOWE JAMES LOWE
  • University of Illinois at Urbana-Champaign, Champaign, United States

The final, formatted version of the article will be published soon.

    Influenza A virus in swine (IAV-S) is common in the US commercial swine population and has the potential for zoonotic transmission. To elucidate influenza shedding the domestic pig population, we evaluated two commercial swine farms in Illinois, USA, for seven weeks. Farm 1 had a recent IAV-S outbreak. Farm 2 has had IAV-S circulating for several years. Forty post-weaning pigs on Farm 1 and 51 pigs from Farm 2 were individually monitored and sampled by nasal swabs for seven weeks. RT-PCR results over time showed most piglets shed in the first two weeks post weaning, with 91.2% shedding in week one, and 36.3% in week two. No difference in the number of pigs shedding was found between the two nurseries. Reinfection events did differ between the farms, with 30% of piglets on Farm 1 becoming reinfected, compared to 7.8% on Farm 2. In addition, whole genome sequencing of nasal swab samples from each farm showed identical viruses circulating between the initial infection and the reinfection periods. Sequencing also allowed for nucleic and amino acid mutation analysis in the circulating viruses. We saw antigenic site mutations arising in some pigs and MxA resistance genes in almost all samples. This study provided information on IAV-S circulation in nurseries to aid producers and veterinarians to screen appropriately for IAV-S, determine the duration of IAV-S shedding, and predict the occurrence of reinfection in the nursery period.

    Keywords: Influenza A virus, Swine, Reinfection, Disease Outbreaks, whole genome sequencing

    Received: 17 Aug 2024; Accepted: 15 Oct 2024.

    Copyright: © 2024 Storms, Leonardi-Cattolica, Prezioso, Varga, Wang and LOWE. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Suzanna M. Storms, University of Illinois at Urbana-Champaign, Champaign, United States

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.