CDC H3N2v Sub-Clade Secret Raises Pandemic Concerns
August 24, 2012
What is H3N2v?
H3N2v is a new flu virus that is currently infecting both pigs and humans in the United States, including Pennsylvania. Although rare, the virus can spread from pigs to people and from people to pigs. This new virus is different from previous H3N2 human infections because it also contains part of the 2009 H1N1 virus. It is the same virus we saw in three ill people who had all attended the Washington County Fair last year in Pennsylvania.
The above description is from the Pennsylvania Department of Health Q&A page on H3N2v. Pennsylvania is currently reporting 31 H3N2v cases (6 confirmed and 25 probable) in at least three counties. However, the description of H3N2v uses a broad definition of the H3N2v with the H1N1pdm09 M gene, which first appeared in an Indiana case in July 2011 (A/Indiana/08/2011). This version was identified in the first 10 human cases in 2011, including the three at the Washington County Fair (A/Pennsylvania/10/2011, A/Pennsylvania/11/2011, A/Pennsylvania/12/2011). This sub-clade has subsequently been found in swine in many states, including four June, 2012 isolates in Ohio.