Location: Virus and Prion Research2013 Annual Report
1a. Objectives (from AD-416):
1. Identify swine influenza virus strain specific antigenic epitopes to support the development of serological assays for surveillance in swine. 2. Compare pathogenesis and transmissibility of selected isolates of the wild-type novel A/HINI virus from animals (e.g., Canadian, Chilean and Argentinean viruses) and correlate with genetic and antigenic changes. 3. Determine efficacy of conventional inactivated swine influenza vaccines against emerging isolates of pandemic A/H1Nl from animals (e.g., Canadian, Chilean and Argentinean viruses). 4. Evaluate a reverse genetics-derived modified live vaccine in pigs and other susceptible animal hosts against pandemic A/H1N1. 5. Evaluate an adenovirus-vectored influenza virus vaccine in pigs.
1b. Approach (from AD-416):
1. Conduct immunological investigations of influenza A virus components that lead to immune responses against specific epitopes that may enable serological surveillance for the 2009 A/H1N1 in swine and determine whether heterologous immunity against endemic swine influenza viruses interferes with serological surveillance methods. 2. Conduct an animal study to determine the pathogenesis and transmissibility of selected isolates of the wild-type novel A/HINI virus from animals and correlate with genetic and antigenic changes. 3. Conduct an animal study to determine the efficacy of conventional inactivated swine influenza vaccines against emerging isolates of pandemic A/H1Nl from animals. 4. Conduct an animal study utilizing a reverse genetics-derived modified live vaccine in pigs and other susceptible animal hosts against pandemic A/H1N1. 5. Conduct an animal study evaluating an adenovirus-vectored H1N1 influenza virus vaccine in pigs.
3. Progress Report:
All previous objectives have been completed and the remaining manuscripts are in preparation. A new study was completed to compare the efficacy of commercial swine influenza A virus (IAV) vaccines with experimental live-attenuated influenza virus (LAIV) vaccines against challenge with H3N2 viruses that reassorted with the H1N1pdm09. One commercial vaccine provided partial protection by reducing nasal shedding, however, indirect contacts acquired virus, indicating the reduction in nasal shedding did not prevent transmission via close contact. One LAIV vaccine provided complete protection and none of the indirect contact pigs became infected or developed antibodies. Clinical disease was not observed in any group, even non-vaccinated animals, a consistent observation in pigs infected with the H3N2 viruses. Thus, clinical presentation is unlikely to identify acutely infected pigs. While vaccination did not fully prevent transmission, paired with additional control measures, it may be of benefit for limiting transmission and spillover at agriculture fairs associated with this particular H3N2 virus.
Vincent, A.L., Ma, W., Lager, K.M., Richt, J.A., Janke, B.H., Sandbulte, M.R., Gauger, P.C., Loving, C.L., Webby, R.J., Garcia-Sastre, A. 2012. Live attenuated influenza vaccine provides superior protection from heterologous infection in pigs with maternal antibodies without inducing vaccine associated enhanced respiratory disease. Journal of Virology. 86(19):10597-10605.