Influenza

Influenza update

28 July 2014 - Update number 216

Summary

Globally influenza activity remained low, but has been gradually increasing in the southern hemisphere.

  • In North America and Europe, overall influenza activity remained at inter-seasonal levels.
  • In eastern Asia, influenza activity reached inter-seasonal levels in most countries with influenza A(H3N2) and influenza B virus predominating. Influenza activity still increased slightly in the southern region of China however, mainly due to influenza A(H3N2) viruses.
  • In northern Africa and western Asia, influenza activity remained low.
  • In the southern hemisphere, influenza activity continued to increase in most countries. In the temperate zone of South America influenza-like illness (ILI) continued to increase but was predominantly due to respiratory syncytial virus (RSV). Influenza A(H3N2) was the most common detected influenza virus. In Australia and New Zealand, the influenza season seemed to have started with ILI and the number of influenza detections increasing. Influenza A(H1N1)pdm09 was the most commonly detected virus in these countries. In South Africa the influenza detection rate increased with influenza A(H3N2) the most frequently detected virus.
  • Based on FluNet reporting (as of 25 July 2014, 07:15 UTC), during weeks 27 to 28 (29 June 2014 to 12 July 2014), National Influenza Centres (NICs) and other national influenza laboratories from 55 countries, areas or territories reported data. The WHO GISRS (Global Influenza Surveillance and Response System) laboratories tested more than 25 675 specimens. 3184 were positive for influenza viruses, of which 2844 (89.3%) were typed as influenza A and 340 (10.7%) as influenza B. Of the sub-typed influenza A viruses, 416 (17.6%) were influenza A(H1N1)pdm09 and 1948 (82.4%) were influenza A(H3N2). Of the characterized B viruses, 89 (97.8%) belong to the B-Yamagata lineage and 2 (2.2%) to the B-Victoria lineage.

Full influenza update


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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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