Grant County Indiana Fair H3N2v Cases Acquired N145K
July 12, 2013
The CDC has released H3N2v sequences from the first 12 cases reported in 2013. Three sets of sequences were released initially (A/Indiana/04/2013, A/Indiana/05/2013, A/Indiana/07/2013) with collection dates between June 20-23, corresponding to cases associated with the Grant County Fair. More recently, two additional sets if sequences were released (A/Indiana/06/2013 and A/Indiana/08/2013), which were collected on June 23 and June 24, indicating these additional sequences were also linked to the Grant County Fair (see map).
All five sets of sequences were closely related to each and had H3 N145K, which was also present in one of the six sequences with later collections. This sequence, A/Indiana/19/2013, was from a sample collected on June 29, and was likely from the case linked to a farm/ Although N145K was present in some of the earlier swine sequences, including those with an N2 matching 2011 human case, it was not present in prior human H3N2v sequences.
However, N145K was present in Fujian H3N2 which circulated in the 2003/2004 season. Fujian H3N2 (represented by A/Fujian/411/2002 and the subsequent vaccine target A/Wyoming/03/2003) was virulent and produced a high Pneumonia & Influenza mortality rate, which included adults and children. The high number of deaths in children was followed by regulations in the United States that required reporting of lab confirmed pediatric deaths. N145K has also been cited in recent publications on influenza antigenic profiling.