Influenza

Influenza update - 272

19 September 2016, - Update number 272, based on data up to 04 September, 2016

Summary

Influenza activity varied in countries of temperate South America, is ongoing in South Africa and increased steadily in the last few weeks in Oceania. Influenza activity in the temperate zone of the northern hemisphere was at inter-seasonal levels.

  • In temperate South America, influenza and respiratory syncytial virus (RSV) activity decreased throughout most of the sub-region. In Chile, influenza-like illness (ILI) and laboratory confirmed influenza and RSV virus detections remained elevated; influenza A(H1N1)pdm09 was predominant with co-circulation of A(H3N2)viruses and influenza B viruses. Influenza activity was low in Argentina and Paraguay, while no influenza activity was reported in Uruguay. In Argentina however, ILI and severe acute respiratory infection (SARI) cases remained elevated. Respiratory syncytial virus activity remained elevated in the region.
  • In the temperate countries of Southern Africa, influenza activity is ongoing, with co-circulation of influenza A(H1N1)pdm09, A(H3N2) and B viruses.
  • In Oceania, influenza virus activity increased slightly in recent weeks, but seems to have reached its peak. Influenza A(H3N2) remained the dominant circulating influenza virus. In contrast, in New Zealand ILI consultation rates remained below the seasonal baseline level, although 43% of ILI samples tested positive for influenza, with influenza A(H3N2) predominating.
  • In the Caribbean countries, influenza and other respiratory virus activity remained low throughout most of the sub-region. The exception was Suriname where the number of SARI cases and hospitalizations continued to increase with parainfluenza virus predominating in the recent weeks. In Central America, influenza virus activity remained low but in most of the countries, detections of non-influenza respiratory viruses stayed elevated 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. Influenza A(H1N1)pdm09 detections continued to decrease in Brazil and Ecuador. In Peru, influenza activity continue to decrease, with influenza A(H1N1)pdm09 and influenza B viruses co-circulating.
  • In tropical countries of South Asia, influenza activity was generally low with seasonal influenza A and B viruses co-circulating in the region.
  • In South East Asia, there was a decreasing trend in influenza detection in recent weeks, with co-circulation of seasonal influenza A and B viruses.
  • Sporadic cases of influenza A(H3N2) virus infection were reported from northern, middle and western Africa in recent weeks, among the few countries reporting data during this period. In East Africa, ongoing elevated influenza B detections were reported by Madagascar. Kenya reported decreasing influenza A(H1N1)pdm09 and A(H3N2) activity.
  • In North America and Europe, influenza activity was low with few influenza virus detections. ILI levels were below seasonal thresholds.
  • Influenza activity was low in temperate Asia.
  • National Influenza Centres (NICs) and other national influenza laboratories from 68 countries, areas or territories reported data to FluNet for the time period from 22 August 2016 to 04 September 2016 (data as of 2016-09-16 03:54:50 UTC).The WHO GISRS laboratories tested more than 42184 specimens during that time period. 2911 were positive for influenza viruses, of which 2271 (78%) were typed as influenza A and 640 (22%) as influenza B. Of the sub-typed influenza A viruses, 301 (18.6%) were influenza A(H1N1)pdm09 and 1313 (81.4%) were influenza A(H3N2). Of the characterized B viruses, 44 (24.9%) belonged to the B-Yamagata lineage and 133 (75.1%) 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.

Share

If you wish to be notified when this page is updated send an e-mail to fluupdate@who.int