Influenza virus activity in the world

1 July 2011

Source: Laboratory confirmed data from the Global Influenza Surveillance Network (GISN).

Virological summary

During weeks 23 to 24 (05 June 2011 to 18 June 2011), globally influenza activity remained low with the exception of several countries in the southern hemisphere, e.g. South Africa, where influenza A(H1N1)2009 virus activity continued to be high with co-circulation of low levels of influenza A(H3N2) and B, and Bolivia, where increased influenza A(H3N2) activity was reported. Elsewhere in the southern and northern hemispheres, only sporadic detections of influenza A(H1N1)2009, A(H3N2) and B viruses were reported.

The vast majority of recently characterized viruses remain antigenically similar to the WHO recommended vaccines for the 2010-2011 northern hemisphere and 2011 southern hemisphere influenza seasons.

During weeks 23 to 24 (05 June 2011 to 18 June 2011), National Influenza Centres (NICs) from 71 countries, areas or territories reported data to FluNet*. A total of 837 specimens were reported as positive for influenza viruses, 583 (69.7%) were typed as influenza A and 254 (30.3%) as influenza B. Of the sub-typed influenza A viruses reported, 83.2% were influenza A(H1N1)2009 and 16.7% were influenza A(H3N2).

(FluNet data as of 28 June 2011 14:00 UTC)

* Some NICs report to FluNet retrospectively leading to updates of previous summary data.

Influenza virus detection by type/subtype in countries, areas or territories:

  • Influenza A(H1N1)2009: Argentina, Australia, Cambodia, Chile, China, Colombia, Côte d'Ivoire, Democratic Republic of the Congo, Dominican Republic, Ghana, India, Kenya, Madagascar, Mauritius, New Zealand, Panama, Russian Federation, South Africa, Sri Lanka, Viet Nam
  • Influenza A(H1N1) (old seasonal virus): no report
  • Influenza A(H3N2): Argentina, Bolivia, Chile, China, Colombia, Ghana, India, Iran (Islamic Republic of), Madagascar, Mexico, Norway, Republic of Korea, Rwanda, South Africa
  • Influenza A(H5): Cambodia
  • Influenza B: Argentina, Cambodia, Cameroon, China, Dominican Republic, El Salvador, Ghana, Honduras, India, Iran (Islamic Republic of), Japan, Kenya, Madagascar, Mauritius, New Zealand, Russian Federation, Rwanda, South Africa, Sri Lanka, Uganda, United Kingdom of Great Britain and Northern Ireland, Uruguay, Viet Nam
  • No influenza detected: Algeria, Angola, Armenia, Austria, Azerbaijan, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Central African Republic, Costa Rica, Denmark, Estonia, Ethiopia, Finland, France, France - New Caledonia, Georgia, Germany, Iceland, Ireland, Jamaica, Lao People's Democratic Republic, Latvia, Lithuania, Mali, Netherlands, Nicaragua, Nigeria, Oman, Pakistan, Panama, Poland, Portugal, Romania, Senegal, Slovakia, Slovenia, Spain, Sweden, Ukraine, Zambia