Influenza

Influenza update - 289

15 May 2017, - Update number 289, based on data up to 30 April, 2017

Summary

Influenza activity in the temperate zone of the northern hemisphere continued to decrease. In the temperate zone of the southern hemisphere, influenza activity reached seasonal thresholds in some countries, but remained low in general. Worldwide, influenza B viruses were predominant.

  • In the temperate zone of the Southern Hemisphere, influenza activity slightly increased in recent weeks. In Chile, ILI activity continued to increase and passed the seasonal threshold.
  • In tropical South America, influenza activity remained low in most of the region, except in Bolivia (Plurinational State of) where influenza activity increased in recent weeks with influenza A(H3N2) viruses predominating. Other respiratory virus activities remained low in general, except in Colombia where elevated activity of respiratory syncytial virus (RSV) continued to be reported.
  • In the Caribbean and Central America countries, respiratory virus activity remained low.
  • In East Asia, influenza activity continued to be reported with all seasonal influenza types/subtypes detected.
  • In Southern Asia, influenza activity decreased in recent weeks.
  • In Western Asia, low influenza activity was reported with influenza B viruses predominant.
  • In South East Asia, influenza activity remained low.
  • In East and West Africa, low influenza activity was reported in recent weeks, with all seasonal influenza types/subtypes detected.
  • In Northern Africa, influenza activity remained low.
  • In Europe, influenza activity continued to decrease to low levels overall. In Northern and Eastern Europe, influenza activity continued to decrease with influenza B viruses predominant. In South West Europe little to no influenza activity was reported.
  • In Central Asia, respiratory illness indicators were at low levels in general and very few influenza virus detections were reported during this period.
  • In North America, overall influenza activity continued to decrease. Increased proportions of influenza B viruses were reported in Canada and in the United States of America in recent weeks. In Mexico, low levels of all seasonal influenza types/subtypes continued to be detected.
  • National Influenza Centres (NICs) and other national influenza laboratories from 103 countries, areas or territories reported data to FluNet for the time period from 17 April 2017 to 30 April 2017 (data as of 2017-05-12 06:57:21 UTC).The WHO GISRS laboratories tested more than 79447 specimens during that time period. 7736 were positive for influenza viruses, of which 2683 (34.7%) were typed as influenza A and 5053 (65.3%) as influenza B. Of the sub-typed influenza A viruses, 642 (45.1%) were influenza A(H1N1)pdm09 and 782 (54.9%) were influenza A(H3N2). Of the characterized B viruses, 396 (51.8%) belonged to the B-Yamagata lineage and 369 (48.2%) to the B-Victoria lineage.

Detailed influenza update

Seasonal update




Source of data