2009 Annual Report 1a.Objectives (from AD-416) 1) Pathogenesis of avian inluenza virus isolates in swine;. 2)Role of avian polymerases in adaptation of swine influenza viruses to swine;. 3)Genetic characterization of swine and avian influenza viruses to swine; and. 4)Preparation of reagents. 1b.Approach (from AD-416) 1) Pathogenesis of avian influenza virus isolates in swine will be evaluated after inoculation into a group of four week old pigs. Microscopic and macroscopic lung lesions and viral replication in lungs and nasal cavities will be determined.. 2)Various reassortant viruses containing avian and/or swine polymerase genes will be established using reverse genetics approaches. These reassortant viruses will be tested for their pathogenic potential in swine.. 3)Swine and avian influenza isolates will be genetically characterized using conventional sequencing approaches.. 4)Hyperimmune sera and various viruses will be made available as reagents. 3.Progress Report This is the third year of a 7-year project that is part of a multi-institutional grant. With the departure of an ARS scientist to Kansas State University, the role of the National Animal Disease Center (NADC) in this grant has changed. The new objective is to conduct animal inoculation studies to test the susceptibility of swine to infection with low pathogenic avian influenza viruses. The animal studies for the third year have been delayed due to the NADC's response to the 2009 pandemic H1N1.