Rhiza Labs FluTracker Forum

The latest series of trH3N2 and trH1N2 swine sequences from 2011 (released at Genbank by Iowa State University) provide additional insight into the evolution of the new human contagion, trH3N2. Although the new swine sequences have key components of the 2011 trH3N2 reported in Indiana (A/Indiana/08/2011), and the Washington County fair in western Pennsylvania (A/Pennsylvania/09/2011, A/Pennsylvania/10/2011, A/Pennsylvania/11/2011), the swine sequences fail to match the constellation of genes fund in all four human cases, providing additional evidence for the emergence of a new human contagion, trH3N2, and another influenza pandemic.

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The 2011 trH3N2 human sequences extended the spread of the 2010 human trH3N2 sequences by retaining 5 of the 8 gene segments. The new contagion has swapped out the other three gene segments, PB1, NA, MP for genes found in earlier human triple reassortants (trH1N1, trH3N2, pandemic H1N1), to create a new human contagion, trH3N2, that can efficiently transmit in humans. As has been mentioned by the CDC and WHO, the 2011 human trH3N2 sequences have acquired a pandemic H1N1 M gene segment, which is critical for the efficient transmission of pandemic H1N1 between humans.

However, the human trH3N2 sequences have also acquired the N2 that was in one of the 2010 Penssylvania cases, A/Pennsylvania/14/2010, as well as a PB1 more closely related to sequences from the Huron County fair (A/Ohio/01/2007 and A/Ohio/02/2007) and this new constellation of genes was in all four 2011 human trH3N2 cases reported to date, and not in any of the reported swine sequences, including the recently released sequences (trH3N2 and trH1N2) from 2010 and 2011.

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And nevertheless, the vaccine targets unchanged rest:

"The recommendation means the WHO has seen little evidence of changes in circulating flu strains that would make the vaccines now in use a poor match for them.

The WHO experts recommended keeping the pandemic 2009 strain for the influenza A/H1N1 component of the vaccine, along with a Perth 2009 strain of A/H3N2 and a Brisbane 2008 strain of influenza B. Officially, the agency advises using strains similar to:

A/California/7/2009(H1N1)pdm09
A/Perth/16/2009 (H3N2)
B/Brisbane/60/2008
The new recommendation means the WHO has chosen the same three strains for the Southern Hemisphere 3 years in a row, as the agency first picked them in September 2009 for the 2010 season. That was when the WHO first chose the pandemic 2009 H1N1 strain for the vaccine on the expectation—which proved correct—that it would replace the previous seasonal H1N1 strain."

http://www.cidrap.umn.edu/cidrap/conten ... luvax.html

This new contagion is not related to current seasonal H3N2. WHO and the CDC are developing a pandemic H3N2 vaccine that uses the H3 and N2 from Minnesota/11/2010 as a target.

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Commentary

http://www.recombinomics.com/News/10041 ... agion.html

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Novel Influenza A Viruses
Five cases of human infection with a novel influenza A virus were reported during the 2010--11 influenza season from three states. All five cases were infected with swine-origin influenza A (H3N2) viruses. Two cases occurred in September (Pennsylvania and Wisconsin), one case in October (Pennsylvania), and two cases in November (Minnesota). Two of the five cases occurred in adults, and three occurred in children. Two of the five cases were hospitalized; all five have recovered fully from their illness. The two cases in Pennsylvania were not related. The cases in Wisconsin and Pennsylvania had direct contact with swine or lived in areas close to swine farms. The two cases from Minnesota occurred in a father (index case) and child. The father had a nasopharyngeal swab positive for swine-origin influenza A (H3N2) virus and had direct swine exposure 6 days before illness onset. The child, whose infection with swine-origin influenza A (H3N2) virus was confirmed several weeks later by serologic testing, did not have direct swine exposure and most likely acquired infection from close contact with her father. Other persons in the same household also had ILI during the same period, but serologic results were either negative or inconclusive.

http://cdc.gov/flu/weekly/weeklyarchive ... ummary.htm

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No new trH3N2 reported for week 40

http://wonder.cdc.gov/mmwr/mmwr_reps.as ... wr_table=1

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Once again trH3N2 disappears from FluView subtyping figure

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A/Maine/06/2011 similar to other 2011 human trH3N2 cases, but somewhat different, signaling widespread trH3N2 in humans in 2011.

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