Influenza virus activity in the world

21 November 2011

Source: Laboratory confirmed data from the Global Influenza Surveillance and Response System (GISRS).

Virological summary

During weeks 43 to 44 (23 October 2011 to 05 November 2011), laboratory confirmed influenza virus detections remained sporadic in most parts of the world. The majority of viruses circulating globally were influenza A and of these A(H3N2) predominated.

In the northern hemisphere overall influenza activity was low with a number of countries in Europe and north America reporting sporadic detections of influenza A(H1N1)pdm09, A(H3N2) and influenza B. In Asia, regional activity of influenza A(H1N1)pdm09 and B viruses persisted since week 29 in Cambodia. Elsewhere in Asia, influenza virus activity of A(H1N1)pdm09, A(H3N2) and B was low.

In central America, influenza activity was low in general with the exception of Nicaragua which continued to report regional outbreaks due to co-circulation of A(H1N1)pdm09 and A(H3N2) viruses.

In the southern hemisphere, local outbreaks of A(H1N1)pdm09 and B continued to be reported in Cameroon since week 31 with an increase in influenza A(H3N2) detections in recent weeks. Influenza A(H1N1)pdm09, A(H3N2) and B viruses continued to circulate at low levels in Africa, Oceania and South America.

FluNet summary

During weeks 43 to 44 (23 October 2011 to 05 November 2011), National Influenza Centres (NICs) from 76 countries, areas or territories reported data to FluNet. A total of 764 specimens were reported as positive for influenza viruses, 492 (64.4%) were typed as influenza A and 272 (35.6%) as influenza B. Of the sub-typed influenza A viruses reported, 31.8% were influenza A(H1N1)pdm09 and 68.2% were influenza A(H3N2).

FluNet data as of 15 November 2011 10:50 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)pdm09: Argentina, Australia, Brazil, Cambodia, Cameroon, Chile, Costa Rica, Czech Republic, Honduras, India, Iran (Islamic Republic of), Jamaica, Kenya, Mexico, Viet Nam
  • Influenza A(H1N1) old seasonal virus: no report
  • Influenza A(H3N2): Australia, Brazil, Cambodia, Cameroon, China, Costa Rica, Cuba, El Salvador, Finland, Ghana, Honduras, India, Iran (Islamic Republic of), Israel, Japan, Kenya, Lao People's Democratic Republic, Mexico, New Zealand, Norway, Republic of Korea, South Africa, Sweden, Togo, Tunisia, United Kingdom of Great Britain and Northern Ireland, United States of America, Viet Nam
  • Influenza B: Australia, Bolivia (Plurinational State of), Cambodia, Cameroon, China, Ghana, India, Israel, Japan, Kenya, Lao People's Democratic Republic, Nepal, New Zealand, Norway, South Africa, Sweden, Togo, Ukraine, United States of America, Viet Nam
  • No influenza detected: Albania, Algeria, Angola, Armenia, Austria, Azerbaijan, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Denmark, Dominican Republic, Estonia, France - New Caledonia, Georgia, Germany, Greece, Guatemala, Iceland, Ireland, Kyrgyzstan, Latvia, Lithuania, Luxembourg, Netherlands, Panama, Paraguay, Poland, Portugal, Republic of Moldova, Romania, Russian Federation, Serbia, Slovakia, Slovenia, Spain, Turkey