Influenza

Influenza virus activity in the world

2 December 2011

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

Virological summary

During weeks 45 to 46 (06 November 2011 to 19 November 2011), laboratory confirmed influenza virus detections in general remained sporadic in most parts of the world.

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. The only country in Europe reporting local outbreaks of influenza was the Netherlands, where A(H3N2) and B viruses co-circulated. In Asia, regional activity of influenza A(H1N1)pdm09 and B viruses continued to persist 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 outbreaks due to co-circulation of A(H1N1)pdm09 and A(H3N2) viruses.

In the southern hemisphere, local outbreaks of A(H1N1)pdm09, influenza A(H3N2)and B continued to be reported in Cameroon. Otherwise sporadic detections of influenza A(H1N1)pdm09, A(H3N2) and B viruses continued to be reported in Africa, Oceania and South America.

Three cases of human infection with a novel influenza A virus in children were recently reported by the United States of America. The virus is a reassortant between the swine-origin Influenza triple reassortant A(H3N2) viruses circulating in the swine population in the United States of America since 1998 and the A(H1N1)pdm09 virus (M gene only). Sequences of whole genomes of the three viruses have been uploaded in GISAID. A candidate reassortant vaccine virus developed from A/Minnesota/11/2010 is available. The WHO Global Influenza Surveillance and Response System (GISRS) has been informed and guidance to laboratories using CDC real-time RT-PCR diagnostic kits to detect this new reassortant virus has been issued.

FluNet summary

During weeks 45 to 46 (6 November 2011 to 19 November 2011), National Influenza Centres (NICs) from 80 countries, areas or territories reported data to FluNet. A total of 1056 specimens were reported as positive for influenza viruses, 614 (58.1%) were typed as influenza A and 442 (41.9%) as influenza B. Of the sub-typed influenza A viruses reported, 31.4% were influenza A(H1N1)pdm09 and 68.6% were influenza A(H3N2).

FluNet data as of 29 November 2011 12:50 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: Belgium, Brazil, Cambodia, Cameroon, Canada, China, Costa Rica, Dominican Republic, France, Kenya, Mexico, Nicaragua, Pakistan, Qatar, Sweden, United States of America, Viet Nam
  • Influenza A(H1N1) old seasonal virus: no report
  • Influenza A(H3N2): Algeria, Australia, Brazil, Cambodia, Cameroon, Canada, China, Costa Rica, Cuba, Denmark, France, Iceland, India, Iran (Islamic Republic of), Ireland, Italy, Japan, Jordan, Kenya, Lao People's Democratic Republic, Mexico, Netherlands, Nicaragua, Norway, Republic of Korea, South Africa, Spain, Sri Lanka, Sweden, Tunisia, Turkey, United Kingdom of Great Britain and Northern Ireland, United States of America, Viet Nam
  • Influenza B: Australia, Cambodia, Cameroon, Canada, China, Cuba, Democratic Republic of the Congo, Dominican Republic, France, Guatemala, India, Iran (Islamic Republic of), Japan, Kenya, Lao People's Democratic Republic, Mexico, Netherlands, Norway, Pakistan, Qatar, Republic of Korea, South Africa, Spain, Sri Lanka, Sweden, Switzerland, United Kingdom of Great Britain and Northern Ireland, United States of America, Viet Nam
  • No influenza detected: Albania, Angola, Argentina, Armenia, Austria, Azerbaijan, Belarus, Bosnia and Herzegovina, Bulgaria, Croatia, Estonia, Finland, Georgia, Germany, Ghana, Greece, Hungary, Indonesia, Israel, Jamaica, Kyrgyzstan, Latvia, Lithuania, Luxembourg, Madagascar, Malta, Morocco, Panama, Poland, Portugal, Republic of Moldova, Romania, Russian Federation, Serbia, Sierra Leone, Slovenia, Ukraine
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Snapshot global influenza virus circulation (GISRS-FluNet, 29 November 2011)