H3N2 Variant Influenza cases reported... Is this the viral swine doom?

It may be the mutant we have all been fearing.

In the last 6 months of 2011, 12 US residents in 5 different states (Indiana, Iowa, Maine, Pennsylvania, and West Virginia) were found to be infected with this influenza A H3N2 variant virus that had genes from avian, swine, and human influenza viruses. Similar viruses have been found in the past in swine but only very rarely infected people. However, this virus, first detected in August, was a little bit different. It contained another genetic change: It had acquired the matrix (M) gene from the 2009 H1N1 pandemic virus.

Although we know that the M gene plays a role in viral assembly and replication, we aren't certain what the addition of this M gene means in terms of illness severity or transmissibility in humans. Similar H3N2 viruses have circulated in US swine since the 1990s, and the H3N2 variant with the 2009 H1N1 pandemic M gene was detected in US swine as early at 2010. August 2011, however, was the first time this virus was found in a person.

Investigations into the 12 cases have shown human infection following contact with swine, as well as limited human-to-human transmission. So far, most illness associated with this virus has been mild and self-limited. However, although all the patients recovered, 3 were hospitalized, all of whom were people with preexisting medical conditions. All but 1 were young children. Limited serologic studies conducted recently at CDC indicate that adults may have some preexisting immunity to H3N2v, whereas children likel






[link to www.medscape.com]