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Global Influenza Activity: Week 52

 

 


# 5233

 


The World Health Organization releases their influenza surveillance reports every two weeks, and their latest – released yesterday – gives us a global glimpse of flu activity through the end of 2010.

 

A few excerpts (slightly reformatted for readability), but follow the links to read it in its entirety.

 

Influenza update - 14 January 2011

14 January 2011 - Summary:

North America is continuing to report increases in influenza activity primarily related to influenza A (H3N2) with lower numbers of influenza type B.

In the United Kingdom, severe and fatal cases are increased compared to 2 weeks ago, associated predominantly with influenza A (H1N1) 2009 and less commonly with influenza type B.

Currently, 25% of intensive care beds in the U.K. are occupied by influenza patients. Notably, the Chief Medical Officer has issued an alert to clinicians warning of increasing rates of bacterial infections often associated with influenza (S. pneumoniae, Group A streptococcus, and meningococcus), though the association with the current influenza circulation is still under investigation.

Severe disease associated with H1N1 (2009) and to a lesser extent influenza type B is also being increasingly reported on the European continent and areas of the Middle East. Tropical areas of the world and the temperate countries of the Southern Hemisphere are currently reporting very little influenza circulation.

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(Dbl click on Map to Enlarge)

 

 

This week, we’ve a new report detailing the 2009 H1N1 oseltamivir (Tamiflu) resistant flu samples detected so far by WHO reporting regions.

 

Resistance is generally caused by a mutation, known as H275Y, where a single amino acid substitution (histidine (H) to tyrosine (Y)) occurs at the neuraminidase position 275.

 

Resistance most often develops spontaneously in a person while they are taking oseltamivir, which is a concern for that patient, but only becomes a wider issue if the resistant virus is passed on to others.

 

In 2008 the old seasonal H1N1 virus went from almost always sensitive to the antiviral to completely resistant, because the virus picked up the mutations needed to convey resistance and transmit efficiently.

 

Thus far, that has not happened with the new 2009 H1N1 virus, with less than 2% of samples examined showing the H275Y mutation.   The concern is, of course, that over time that could change.

 

Three new samples were detected in the latest reporting period (29 December 2010- 12 January 2011), bringing the cumulative total to 319.

 

 

Update on oseltamivir resistance to influenza H1N1 (2009) viruses

 

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