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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Virus and Prion Research » Research » Research Project #437036

Research Project: The Study of Influenza A Viruses in the Swine Host

Location: Virus and Prion Research

Project Number: 5030-32000-120-024-I
Project Type: Interagency Reimbursable Agreement

Start Date: Sep 30, 2019
End Date: Sep 29, 2024

Objective:
The following studies will be performed to assess the pathogenicity, transmissibility, infectivity and antibody response to swine and seasonal influenza viruses and/or candidate vaccine viruses. 1. Assess in vivo pathogenicity, transmissibility and infectivity of swine and seasonal influenza viruses and/or candidate vaccine viruses in swine using a simulated natural route of ex-posure (i.e., intranasal inoculation). 2. Understand the host response to swine and seasonal influenza viruses and/or candidate vaccine viruses in swine, with particular emphasis on obtaining post-infection antisera for antigenic characterization. 3. Detection of novel or emerging swine influenza viruses in select U.S. swine populations by active surveillance, mobile sequencing and genetic characterization.

Approach:
Studies will be conducted in BSL-2 enhanced or BSL-3 enhanced facilities. Multiple viruses and vaccine candidates will be tested per year using the below study design. Field surveillance will be performed on select swine populations on farms or agricultural exhibition settings. 1. Conduct in vivo pathogenicity, transmissibility and infectivity testing in pigs via intranasal inoculation. Infectivity and transmissibility will be assessed by virus shedding from swabs taken on sequential days post inoculation from infected animals and those placed in direct or aerosol contact with infected animals. Tissues tropism and pathogenesis will be assessed by examination for virus in various organs and performance of histological examination. In addition, infectivity will be assessed by testing for seroconversion using ELISA, HI and or neutralization assays. 2. Conduct in vivo experiments in pigs to compare and contrast the swine host immune response using multiple serological assays. Antisera will be collected from the in vivo studies for use in diagnostic reagent development and antigenic characterization. 3. Novel or emerging swine influenza viruses will be detected by active surveillance on farms or agricultural exhibitions. Mobile sequencing will be used to subtype and sequence viral genomes. Genetic characterization using phylogenetic and bioinformatics tools will be used to identify viruses with novel or emerging genotypes and allow for selection of samples for virus isolation and further phenotypic testing.