Swine flu fair pigs appeared normal

Researchers testing pigs for influenza A viruses at Ohio county fairs found that infected animals typically appear clinically normal, demonstrating the challenges health officials faced in preventing variant influenza from spreading this summer.

The Ohio State University group tested pigs for the past three years, starting in Ohio in the summer of 2009 during the pandemic of H1N1 influenza. The researchers tested pigs at 53 county fairs through 2011 and detected influenza A viruses in pigs at 12 of the fairs, CIDRAP News reports.

The team found H1N2 and H3N2 swine flu viruses in 2009, H3N2 swine influenza viruses in 2010, and H1N2 along with H3N2 in 2011. In 2011, however, all isolates had the matrix gene from the pandemic human 2009 H1N1 virus. So far in 2012, the researchers have detected H3N2 influenza A viruses again with the matrix gene.

The researchers noted that visual examinations were not necessarily good indicators for identifying infected pigs. They said that testing healthy pigs, not just sick ones, will help researchers to characterize a more complete spectrum of influenza A viruses.

The team, led by Andrew Bowman, proposed potential strategies to reduce the prevalence of influenza A virus infections in county fair pigs to protect both humans and pigs. The solutions include a shortening of the swine exhibition period, vaccinating fair pigs against appropriate influenza A viruses and preventing the inter-fair movement of pigs, according to CIDRAP News.