Sunday, September 30, 2012

Seasonal Influenza vs. Variant Influenza

This is last weeks chart of the Seasonal Influenza thru the CDC. To view the weekly stats of our seasonal flu (chart below), click on the category in the right side bar entitled:  "Worldwide Update on Influenza Activity".    In the chart below, the 2009 H1N1 is our seasonal H1N1 from the pandemic in 2009.  The A(H3) is part of our seasonal flu, and therefore part of the flu shot that you receive.  I don't know what would be in the A (Subtyping not performed) statistic below, and the B is also part of our normal Seasonal Flu, and covered in our yearly flu shots.

As part of the reorganization of this blog.I have simplified the page.  Specifically,  the right side-bar has been organized to  categorize the influenza strains that post a danger that are not part of our weekly seasonal influenza surveillance.  Note the list of influenza's. They are all found on the right side-bar of this blog. You can read about them and familiarize yourself with them.

  1. Coronavirus - This new coronavirus has been laboratory confirmed in only two cases globally to date: both occurred between July - September 2012.  Tranmission appears to be very limited as, if it were very contagious, we would have expected to have seen more cases in other countries or the people caring for these two cases, the first of which occurred over three months ago.
  2. H1N1 Ontario  -  The H1N1 variant influenza virus (H1N1v) is a non-human influenza virus that normally circulates in animals and rarely infects humans. When these viruses infect humans, they are termed “variant” viruses.
    The H1N1v virus doesn't spread easily from swine to people—and even less easily from person to person. In most cases, the virus causes only mild illness in people.  Currently the human case in Ontario is in critical condition.
  3. H1N1v  -  A recently adopted naming convention for viruses that commonly circulate in swine uses a “v” (for “variant”) when these viruses infect humans, regardless of whether the virus contains the 2009 H1N1 M gene. Following this convention, the Wisconsin virus will be called H1N1v.  The virus identified in Wisconsin has genes from avian, swine and human influenza viruses, making it a so-called “triple reassortant” (tr) virus. Triple reassortant viruses have been circulating in U.S. swine since the 1990s. However the virus detected in Wisconsin is different from earlier triple reassortant influenza A H1N1 viruses in swine (tr-H1N1) in that it has acquired the matrix [M] gene) from the 2009 influenza A (H1N1) virus.
  4. H3N2v  -  This genetic change (acquisition of the 2009 H1N1 virus matrix [M] gene) has been seen in triple reassortant H3N2 viruses that have infected 12 people since August 2011. (These cases occurred in West Virginia (2), Indiana (2), Pennsylvania (3), Maine (2), and Iowa (3).) These variant H3N2 viruses are being called “H3N2v.”
  5. H5N1 - When humans become ill with H5N1 virus infection, severe illness and death may occur. Sporadic human cases mainly occur after contact with infected poultry that were sick or dead, and have been reported in 15 countries.   H5N1 influenza viruses have been circulating among birds for many years, some are highly pathogenic, and infections in humans are uncommon.  There have been no recent changes that pose any additional risk to humans.
  6. H5N1 Clade - Over time, H5N1 viruses have evolved into different groups, called “clades.” Since 2007, 12 different clades of H5N1 viruses have been identified. The FAO report and subsequent media stories focused on an H5N1 virus that has been given a nomenclature (name) of “clade”.  The clade viruses are very active viruses and are spreading more widely in poultry and wild birds. While this increases the possibility of human exposures to infected birds or poultry, it does not increase their ability to infect and transmit between people. However, as part of the U.S. government’s pandemic preparedness activities, a vaccine virus candidate to protect humans against this virus already has been created so that vaccine production could begin rapidly if this virus were to change to infect humans and spread easily from person to person. The vaccine virus candidate is an exact match to currently circulating viruses.
  7. Worldwide Update on Influenza Activity - weekly updates on the World's Influenza Activity are to be found here.  The chart above, in this post, can be found at this link.

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