Influenza

Influenza update

15 December 2014 - Update number 226

Summary

Globally, influenza activity increased in the northern hemisphere and in several countries has passed the seasonal threshold. Influenza A(H3N2) viruses predominated so far.

  • In North America, the levels of influenza activity, mainly associated with A(H3N2) virus, passed the seasonal threshold.
  • In Europe overall influenza activity continued to increase, though with no clear indication that the influenza season had begun.
  • In eastern Asia, influenza activity increased with, influenza A(H3N2) predominated.
  • In northern and western Africa influenza activity increased with influenza B virus predominant.
  • In tropical countries of the Americas, influenza activity increased in some countries of the Caribbean, decreased in Central America and was low in the tropical countries of South America.
  • In tropical Asia, influenza activity was low.
  • In the southern hemisphere, influenza activity remained at a low level, but ILI activity remained high in several Pacific Islands.
  • Based on FluNet reporting (as of 11 December 2014, 14:25 UTC , during weeks 47 to 48 (16 November 2014 to 29 November 2014), National Influenza Centres (NICs) and other national influenza laboratories from 49 countries, areas or territories reported data. The WHO GISRS laboratories tested more than 59 940 specimens. 7227 were positive for influenza viruses, of which 6603 (91.4%) were typed as influenza A and 624 (8.6%) as influenza B. Of the sub-typed influenza A viruses, 84 (2.4%) were influenza A(H1N1)pdm09 and 3472 (97.6%) were influenza A(H3N2). Of the characterized B viruses, 140 (97.2%) belonged to the B-Yamagata lineage and 4 (2.8%) to the B-Victoria lineage.
  • Due to changes in data collection platforms, data from the WHO Regional Office for Europe are temporarily not available at the global level. Those data will be uploaded to FluNet and FluID as soon as possible. Information on European influenza activity can be found at http://www.flunewseurope.org/

Full influenza update

Seasonal update


For regional updates on influenza see the following links


For updates on the influenza at the human-animal interface see the following WHO web pages:


Source of data

The Global Influenza Programme monitors influenza activity worldwide and publishes an update every two weeks.
The updates are based on available epidemiological and virological data sources, including FluNet (reported by the WHO Global Influenza Surveillance and Response System) and influenza reports from WHO Regional Offices and Member States. Completeness can vary among updates due to availability and quality of data available at the time when the update is developed.

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