Hawaii Match With Indiana and Ohio Signals H3N2v Pandemic
August 3, 2012
The CDC has released a series of H3N2v sequences from the recently confirmed cases in Hawaii (A/Hawaii/03/2012), Ohio (A/Ohio/13/2012 from Butler County), and Indiana (A/Indiana/12/12 from Jackson County). Full or partial sequences were generated for all 8 gene segments by sequencing of the clinical sample. In additional partial sequences were generated for the two confirmed LaPorte County cases (A/Indiana/06/2012 and A/Indiana/08/2012) which were not cloned.
All of these sequences were closely related in all gene segments and matched the two earlier sequences from Laporte (A/Indiana/07/2012 and A/Indiana/09/2012) which were closely related to the sequences from the Mineral County daycare center (A/West Virginia/06/2011 and A/West Virginia/07/2011) which involved 23 symptomatic contacts and no swine exposure. These sequences were also related to the first cases in 2012, A/Utah/10/2012.
All human H3N2v cases since November 2011 represent a novel sub-clade that efficiently transmits in humans (H2H), as seen at the West Virginia daycare center, and swine (S2S as seen at the LaPorte County Fair where 12/12 swine were H3N2v confirmed). Thus, this novel sub-clade transmits H2H, S2S, H2S, and S2H leading to significant transmission at county fairs with swine, especially in areas like Jackson County, Indiana where there have been symptomatic human cases for the past 6 weeks.
The presence of the same novel sub-clade in all human cases since late 2011 indicates transmission is sustained, but poorly detected in cases without swine exposure.