H1N1pdm09 PA In Illinois and Indiana H3N2v Cases…”These acquisitions signal further human adaptation that increase pandemic concerns.”(Not Good!! Prepare!!)
August 14, 2013
The CDC has released a full set of H3N2v sequences from the first 2013 confirmed cases in Illinois, A/Illinois/03/2013, as well as the most recent case in Indiana, A/Indiana/11/2013 (14th 2013 Indiana confirmed case). As was seen in the case in Virginia (Ohio resident who visited an agricultural fair in northwestern Virginia), A/Ohio/05/2013, both of the newly released sequences included an H1N1pdm09 PA gene segment (in addition to a H1N1pdm09 M gene segment). Moreover, the two most recent PA sequences were identical and differed from the Virginia sequences at two positions (the three human PA sequences were much more closely related to each other than any reported H1N1pdm09 PA sequence in swine).
Thus, the three most recent human H3N2v cases have H1N1pdm09 PA, increasing the total number of gene segments with a recent history of efficient transmission in humans to five. In the early 1990’s three human genes (H3, N2, PB1) were identified in swine. All human H3N2v sequences (first case was in 2009) have H3 and N2 that trace back to seasonal H3N2 circa 2003. The acquisition of H1N1pdm09 M gene in 2011 and PA in 2013 create a majority for human lineage genes in human H3N2v isolates.