1a.Objectives (from AD-416):
To establish a tool for optimal H9 subtype avian influenza vaccine strain selection by developing an antigenic map of H9 subtype avian influenza virus and correlating vaccine efficacy with antigenic distances.
1b.Approach (from AD-416):
The H9 subtype is the most common avian influenza virus (AIV) subtype in commercial poultry in the world today and is endemic in poultry in Asia and the Middle East where it causes substantial economic losses. H9 AIV is often controlled by vaccination, but there is evidence that like other influenza subtypes, that antigenic variation has occurred resulting in decreased vaccine efficacy. A tool to select the most efficacious vaccines strains by improving antigenic matching is needed to aid control efforts. We aim to develop an antigenic map of H9 AIV with numerous H9 AIVs from around the world using multi-dimensional scaling methods. Once this map is established reference reagents can be selected so that additional isolates can be included. As a second part of the work we will establish criteria for the limits of detection so that antigenic map units can be associated with protection which is critical for vaccine strain selection.
This research is directly related to inhouse objective 1 - Characterize variant and emerging avian influenza viruses in live poultry markets and commercial production systems; inhouse objective 3 - Identify genetic and biological determinants of avian influenza virus susceptibility and resistance in avian species; inhouse objective 4 - Improve existing diagnostic tests and testing strategies for avian influenza virus surveillance, detection, and recovery from disease outbreaks.
Work on this project was initiated during October of 2011. During FY13 additional sera was produced as the most recent isolates from Israel became available. Once the anti-sera production was completed numerous tests were run with the serum to determine how closely related all isolates are to each other. The data was analyzed with a computer program to build the map of the relationships among the isolates. This map will be used to select which isolates to test for use as vaccines in chickens.