Influenza

Influenza update - 263

16 May 2016, - Update number 263, based on data up to 01 May, 2016

Summary

Influenza activity in the northern hemisphere continued to decrease. A predominance of influenza B virus activity continued to be reported in most of the northern hemisphere and in some tropical areas. In a few countries in the southern hemisphere, slight increases in influenza-like illness (ILI) activity were reported.

  • In North America, influenza activity continued to decrease with influenza B detections predominating.
  • Europe and temperate Asia reported decreased influenza activity with a continued predominance of influenza B virus activity.
  • In North Africa, influenza activity continued to decrease in general, except in Egypt where in recent weeks influenza B activity continued.
  • Influenza A virus was reported predominant in Eastern and Western Africa.
  • In Central America and the Caribbean countries, influenza and other respiratory virus activity remained generally low, although levels of A(H1N1)pdm09 virus activity remained elevated in El Salvador and Guatemala. Active circulation of influenza A(H1N1)pdm09 activity was also reported in several countries in the Caribbean.
  • In parts of tropical South America, low but increasing influenza A(H1N1)pdm09 activity was reported in Bolivia and Ecuador. In Peru, influenza detections decreased. In Brazil, influenza activity continued at elevated levels with a predominance of influenza A(H1N1)pdm09 virus. Respiratory syncytial virus (RSV) activity remained elevated in Colombia.
  • In tropical countries of South Asia, influenza activity decreased with influenza B virus predominant.
  • In temperate South America, respiratory virus activity remained low. ILI activity increased slightly in a few countries but remained below seasonal thresholds.
  • In the temperate countries of Southern Africa and Oceania, influenza virus activity remained low. Some islands in the Pacific reported increased ILI activity.
  • National Influenza Centres (NICs) and other national influenza laboratories from 90 countries, areas or territories reported data to FluNet for the time period from 18 April 2016 to 01 May 2016 (data as of 2016-05-13 03:33:09 UTC).The WHO GISRS laboratories tested more than 85968 specimens during that time period. 12819 were positive for influenza viruses, of which 4580 (35.7%) were typed as influenza A and 8239 (64.3%) as influenza B. Of the sub-typed influenza A viruses, 1728 (81.5%) were influenza A(H1N1)pdm09 and 391 (18.5%) were influenza A(H3N2). Of the characterized B viruses, 353 (20.6%) belonged to the B-Yamagata lineage and 1358 (79.4%) to the B-Victoria lineage.

Detailed 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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