Influenza

Influenza update - 262

02 May 2016, - Update number 262, based on data up to 17 April, 2016

Summary

Influenza activity in the Northern Hemisphere continued to decrease. A predominance of influenza B virus activity continued to be reported in parts of North America, in Northern Temperate Asia, South-East Asia and in parts of Europe. 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 A(H1N1)pdm09 and influenza B viruses co-circulating.
  • Europe and Northern temperate Asia reported influenza activity decreased with a continued predominance of influenza B virus activity.
  • In North Africa and West Africa, influenza activity continued to decrease, with influenza A virus predominant, while influenza activity remained low in the other regions in Africa.
  • In Central America and the Caribbean countries, influenza activity in general was low. In Jamaica, severe acute respiratory infection (SARI) continued to decrease but remained elevated. In Guatemala and El Salvador, an increase in influenza activity was reported mainly due to influenza A(H1N1)pdm09 virus.
  • In parts of tropical South America, low but increasing influenza A(H1N1)pdm09 activity was reported. In Brazil, influenza activity was already above expected levels for this time of year with influenza A(H1N1)pdm09 virus predominating. Respiratory syncytial virus (RSV) activity remained elevated in Colombia.
  • In tropical countries of South Asia, influenza activity remained low.
  • In Temperate South America, an increase in ILI and SARI activities were reported in Argentina and Paraguay.
  • In the rest of the temperate countries of the Southern Hemisphere, influenza virus activity remained low.
  • National Influenza Centres (NICs) and other national influenza laboratories from 90 countries, areas or territories reported data to FluNet for the time period from 04 April 2016 to 17 April 2016 (data as of 2016-04-29 03:39:10 UTC).The WHO GISRS laboratories tested more than 105838 specimens during that time period. 20933 were positive for influenza viruses, of which 9821 (46.9%) were typed as influenza A and 11112 (53.1%) as influenza B. Of the sub-typed influenza A viruses, 3758 (84.8%) were influenza A(H1N1)pdm09 and 673 (15.2%) were influenza A(H3N2). Of the characterized B viruses, 481 (17.7%) belonged to the B-Yamagata lineage and 2231 (82.3%) 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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