# 1394
CIDRAP (Center for Infectious Disease Research and Policy), located at the University of Minnesota, has a good article on the recently revealed swine/avian flu virus discovered in Missouri.
New swine flu virus supports 'mixing vessel' theory
Robert Roos
News Editor
Dec 20, 2007 (CIDRAP News) – A new influenza virus discovered in Missouri pigs has a combination of genes from avian and swine flu viruses, supporting the theory that pigs can serve as a mixing vessel for flu viruses and a potential source for a human pandemic strain, according to a report published yesterday.
Researchers found that the virus, an H2N3 subtype, caused illness in experimentally infected mice and was transmissible in swine and ferrets, suggesting it has adapted to mammals, according to the report, published in the Proceedings of the National Academy of Sciences (PNAS). In addition, genetic analysis showed the virus has a mutation linked with an increased ability to infect mammals.
The discovery marks the first identification of an H2 virus in swine, according to the authors of the report. The flu pandemic of 1957-58 was caused by an H2 virus, namely H2N2. That virus was replaced by an H3N2 strain in the pandemic of 1968-69, and H2 viruses have not circulated in humans since then. Hence, people younger than 40 have little immunity to H2 viruses, scientists say.
"Our results provide further evidence for the potential of swine to promote reassortment between different influenza viruses, and the genetic and biologic properties of the H2N3 viruses described suggest that it would be prudent to establish vigilant surveillance in pigs and in workers who have occupational exposure," states the PNAS report.
It was written by scientists from Iowa State University and the US Department of Agriculture's (USDA's) Agricultural Research Service (ARS), both in Ames, Iowa; the University of Minnesota in St. Paul; and St. Jude Children's Research Hospital and the University of Tennessee, both in Memphis. The lead author is Wenjun Ma of Iowa State and the USDA.
