Influenza activity in the world

13 November 2009

This summary provides an updated summary of both pandemic influenza A (H1N1) 2009 virus and seasonal influenza activity for weeks 42-43 of 2009 (as of 13 November 2009). Detailed reports of the pandemic influenza A (H1N1) virus activity are available at: the WHO page for Pandemic (H1N1) 2009 . This summary does not include reports of avian influenza in humans, which are available at: the WHO avian influenza page .

Pandemic (H1N1) 2009

During the weeks 42-43, the pandemic influenza A (H1N1) 2009 virus was the predominant circulating strain of influenza in all of the countries with influenza activity. Increased activity due to this virus was reported in the northern hemisphere in Asia, Canada, Europe and the United States of America. In temperate regions of the Southern Hemisphere, activity due to 2009 H1N1 had returned to below baseline. In tropical regions of the Americas and Asia, influenza activity due to 2009 H1N1 remained variable.

In the northern hemisphere, widespread outbreaks of pandemic influenza A (H1N1) 2009 were reported in the 48 states in the United States of America, many regions in Canada and some countries in Europe and Asia. These countries included Belgium, Iceland, Japan, Luxembourg, Netherlands, Norway and the United Kingdom.

Regional outbreaks were reported in China, Germany, Malta, Mongolia, Spain, Sweden and some parts of the Russian Federation. Afghanistan, Algeria, Belarus, China Hong Kong Special Administrative Region, Hungary, Islamic Republic of Iran, Israel, Italy, Morocco and Ukraine reported local levels of pandemic influenza A (H1N1) activity.

Sporadic pandemic influenza A (H1N1) 2009 activity was reported in Australia, Austria, Argentina, Brazil, Bosnia and Herzegovina, Bulgaria, Côte d' Ivoire, Croatia, Czech Republic, Denmark, France, Kenya, Lithuania, New Zealand, Poland, Portugal, Republic of Moldavia, Romania, Slovakia, Slovenia, Sri Lanka, Switzerland, Turkey and Tunisia.

Seasonal influenza

The level of seasonal influenza activity in most countries was low with only sporadic detections except in China where local outbreaks of H3 were reported as well as low levels of H1 and B. Sporadic seasonal influenza activity was observed in Australia (H3), Canada (H1,H3,B), China Hong Kong Special Administrative Region (H1,H3,B), Kenya (H1,H3,B), Russian Federation (H1,H3,B), Senegal (H3) and Tunisia (H3,B).

Azerbaijan, Chile, Estonia, Georgia, Greece, Kyrgyzstan, Latvia, Lithuania, Serbia and Uzbekistan reported no influenza activity.