Influenza

Influenza update - 270

22 August 2016, - Update number 270, based on data up to 07 August, 2016

Summary

Influenza activity varied in countries of temperate South America and increased steadily in the last few weeks in South Africa, increased slowly but remained still low overall in most of Oceania. Influenza activity in the temperate zone of the northern hemisphere was at inter-seasonal levels.

  • In temperate South America, influenza-like illness (ILI) activity and severe acute respiratory infection (SARI) indicators have plateaued in Chile and Paraguay. Influenza activity remained elevated in Chile and plateaued in Paraguay, while Uruguay saw no influenza activity reported. Influenza A(H1N1)pdm09 virus co-circulated with influenza B viruses in Chile and Paraguay. In Argentina however, influenza activity continued to decrease, and ILI and SARI cases remained elevated but did not increase. Respiratory syncytial virus (RSV) activity remained elevated in the region.
  • In the temperate countries of Southern Africa, influenza detections among ILI patients continued to rise, with a recent shift from influenza B to predominantly influenza A viruses. Among patients with pneumonia, the incidence of RSV detections continued to decline compared to recent reporting periods.
  • In Oceania, influenza virus activity slightly increased but remained low overall. Influenza A(H3N2) viruses predominated in Australia and New Caledonia where influenza activity increased in recent weeks with several A(H1N1) virus also detected. Levels of influenza activity remained low in New Zealand for this time of the year.
  • In the Caribbean countries, influenza and other respiratory virus activity continued at low levels. SARI cases and hospitalizations decreased slightly in several countries, while in Cuba the number of SARI cases slightly increased in the recent weeks. In Central America, influenza and other respiratory virus activity remained low or decreased in most of the countries. In Panama, detections of non-influenza respiratory viruses remained elevated but not increasing. In Costa Rica, influenza activity remained low while other respiratory virus activity continued to increase with RSV predominating. In tropical South America, influenza A(H1N1)pdm09 and RSV virus detections generally decreased in recent weeks or remained low in most of the countries. In Colombia, SARI activities continued to decrease and reached a similar level compared to the same period last year. Influenza A(H1N1)pdm09 detections continued to decrease in Ecuador and in the Plurinational State of Bolivia. In Peru, influenza activity increased during the last week with influenza B predominating while detection of other respiratory viruses decreased, with RSV predominating. In Brazil and Ecuador influenza A(H1N1)pdm09 activity remained low.
  • In tropical countries of South Asia, influenza activity was generally low with influenza A and B viruses co-circulating in the region.
  • In South East Asia, there has been an increase in influenza detection in recent weeks, with influenza A and B viruses co-circulating.
  • In the northern temperate and central tropical regions of Africa, influenza activity was generally low with influenza A(H3N2) virus detections predominant in Western Africa and influenza B virus detections predominant in Eastern and Northern Africa, among the few countries reporting data during this period.
  • In North America and Europe, influenza activity was low with influenza B predominant. ILI levels were below seasonal thresholds.
  • Influenza activity was low in temperate Asia.
  • National Influenza Centres (NICs) and other national influenza laboratories from 50 countries, areas or territories reported data to FluNet for the time period from 25 July 2016 to 07 August 2016 (data as of 2016-08-19 04:04:59 UTC).The WHO GISRS laboratories tested more than 31890 specimens during that time period. 1654 were positive for influenza viruses, of which 1096 (66.3%) were typed as influenza A and 558 (33.7%) as influenza B. Of the sub-typed influenza A viruses, 319 (32.9%) were influenza A(H1N1)pdm09 and 652 (67.1%) were influenza A(H3N2). Of the characterized B viruses, 70 (35.7%) belonged to the B-Yamagata lineage and 126 (64.3%) 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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