Agricultural Research Service researchers have identified a new strain of swine influenza -- H2N3 -- that belongs to the group of H2 influenza viruses that last infected humans during the 1957 pandemic. This new strain has a molecular twist: It is composed of avian and swine influenza genes.
ARS veterinarians Juergen Richt, Amy Vincent, Kelly Lager and Phillip Gauger conducted this research with Iowa State University visiting scientist Wenjun Ma, ISU veterinarian Bruce Janke and other colleagues at the University of Minnesota and St. Jude Children's Research Hospital. The ARS veterinarians work at the agency's National Animal Disease Center in Ames, Iowa.
The research team studied an unknown pathogen that in 2006 infected two groups of pigs at separate production facilities. Both groups of pigs used water obtained from ponds frequented by migrating waterfowl. Molecular studies indicated the unknown pathogen was an H2N3 influenza virus closely related to an H2N3 strain found in mallard ducks. However, this was the first time it had been observed in mammals.