Influenza activity in the world
6 January 2005

Influenza activity increased slightly in some countries in Africa, Europe and North America, with an increasing number of influenza viruses detected and/or overall influenza-like illness (ILI) consultation rate reported. In general, levels of influenza activity remained medium-low in most parts of the world. So far this season, most influenza viruses characterized by the WHO Global Influenza Surveillance Network are A/Fujian/411/2002(H3N2)-like and B/Shanghai/361/2002-like viruses.

- Weekly Epidemiological Record (WER) - 27 February 2004, vol. 79, 9 (pp 85-92)

Reports from individual countries

Belgium. Overall influenza activity remained sporadic, although the number of influenza A viruses detected weekly increased since week 48.

Canada.Widespread influenza activity was reported in Quebec in week 51 and in 1 region of British Columbia in week 52. The number of influenza outbreaks increased significantly in weeks 5152. Most influenza viruses characterized in the National Influenza Centre of Canada were A(H3N2) viruses.

Iceland. Influenza activity increased slightly in weeks 51-52.

Ireland. Since week 49, influenza activity remained sporadic with a slightly increasing number of influenza A¹ viruses detected weekly.

Italy. Increasing but still low activity of influenza was reported for weeks 51-52.

Japan. A local outbreak associated with influenza B virus was reported in week 51. Overall influenza activity remained low.

Madagascar. An increase in ILI consultation rate was observed since week 49 with local activity of A(H3) reported for weeks 50-51.

Russian Federation. ILI consultation rate was within baseline levels in most regions of the Russian Federation except in one city, Arkhangelsk, where regional activity of influenza was reported.

Spain. Influenza A activity in Castilla y León increased in week 52 but remained local.

Sweden. The number of influenza A viruses detected increased in weeks 51-52. Overall influenza activity remained low.

United Kingdom. An increase of influenza activity was observed in week 52, but the overall ILI consultation rate remained within baseline levels. Two respiratory illness outbreaks in week 50 were confirmed as an A(H3) outbreak and a respiratory syncytial virus outbreak.

United States. Influenza activity increased in weeks 51-52. Widespread activity was reported in Delaware, New York State and New York city, and regional activity was reported in 6 states for week 52, when the overall ILI consultation rate was slightly below baseline. Of 60 influenza viruses characterized so far in the United States Centers for Disease Control and Prevention, Atlanta, 42 were influenza A(H3N2) and 18 were B viruses.

Other reports. During weeks 51 and 52, low influenza activity was detected in Argentina (B), Austria (A), Hong Kong Special Administrative Region of China (H3 and B), Denmark (H1), France (H1, H3 and B), Hungary, Israel (A and B), Latvia (H3 and B), Mexico (B), Norway (H3 and B), Portugal (H3 and B), Slovenia (A), Switzerland (H1 and B), Tunisia (H1) and Ukraine.

¹A = A non-subtyped.

- Index of the Weekly Epidemiological Record (WER)