Influenza

Influenza virus activity in the world

15 July 2011

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

Virological summary

During weeks 25 to 26 (19 June 2011 to 2 July 2011), influenza activity increased in some countries in the southern hemisphere. Regional activity of influenza A(H1N1)2009 was reported in Argentina, while in the Dominican Republic, high numbers of laboratory confirmed influenza A(H1N1)2009 and influenza B were detected. In Africa, South Africa continued to report widespread activity due to influenza A(H1N1)2009 with co-circulation of A(H3N2) and B at lower levels. In Oceania, increased detections of influenza A(H1N1)2009 and influenza B were recorded in Australia while outbreaks of influenza B were reported in New Zealand. Sporadic detections of influenza A(H1N1)2009, A(H3N2) and B were reported in a number of other countries in the southern hemisphere.

In the northern hemisphere, low numbers of influenza A(H1N1)2009, A(H3N2) and B viruses have been detected with the exception of Cambodia where local outbreaks of influenza A(H1N1)2009 and influenza 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 25 to 26 (19 June 2011 to 2 July 2011), National Influenza Centres (NICs) from 62 countries, areas or territories reported data to FluNet*. A total of 792 specimens were reported as positive for influenza viruses. 602 of the 792 (76%) were typed as influenza A and 190 (24%) as influenza B. Of the sub-typed influenza A viruses reported, 61.3% were influenza A(H1N1)2009 and 38.7% were influenza A(H3N2).

(FluNet data as of 12 July 2011 11:40 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, Brazil, Cambodia, Chile, Colombia, Dominican Republic, Ghana, India, Kenya, Madagascar, Nepal, Singapore, South Africa, Sri Lanka, Thailand, Viet Nam
  • Influenza A(H1N1) (old seasonal virus): no report
  • Influenza A(H3N2): Argentina, Australia, Bolivia (Plurinational State of), Brazil, China, Colombia, Cuba, Democratic Republic of the Congo, Ethiopia, Germany, Ghana, India, Japan, Madagascar, New Zealand, Singapore, South Africa, Thailand
  • Influenza A(H5): no report
  • Influenza B: Australia, Cambodia, Cameroon, China, Dominican Republic, El Salvador, Ghana, Japan, Kenya, Lao People's Democratic Republic, Madagascar, Mauritius, Nepal, New Zealand, Rwanda, Singapore, South Africa, Sri Lanka, Thailand
  • No influenza detected: Algeria, Angola, Armenia, Austria, Azerbaijan, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Central African Republic, Costa Rica, Democratic Republic of the Congo, Denmark, Ecuador, Estonia, France - New Caledonia, Georgia, Honduras, Iceland, Iran (Islamic Republic of), Jamaica, Latvia, Lithuania, Mexico, Netherlands, Nicaragua, Norway, Panama, Paraguay, Republic of Korea, Romania, Russian Federation, Senegal, Slovakia, Slovenia, Sweden, Turkey
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Snapshot global influenza virus circulation (GISN-FluNet, 12 July 2011)