Seasonal Flu: International Situation Update

November 24, 2010, 2:00 PM ET

Global Flu Activity Update, November 24, 2010

The following summary of key influenza-related updates was created from regional World Health Organization (WHO) reports, country reports, CDC field staff updates and other sources. Updates are listed by region and focus on data collected during epidemiologic Weeks 43 - 44.

Map of International Activity Estimates

Temperate Climate Areas

Northern Hemisphere

Europe

According to the European Centre for Disease Prevention and Control, influenza activity intensity in Week 44 was low in all of the 24 European Union countries reporting, except for Bulgaria, which reported medium intensity. Twenty-two out of 369 (6.0%) sentinel specimens were influenza-positive, an increase from Week 43 when 15 out of 309 (4.9%) sentinel specimens were influenza-positive.

Canada

According to the Public Health Agency of Canada, the influenza-like illness (ILI) consultation rate in Week 44 was at a level expected for the week (based on a 13-year average rate) and well below the level reported in Week 44 of 2009. Among subtyped influenza-positive specimens from provincial laboratories, influenza A (H3N2) was the predominant influenza strain. Since the beginning of the 2010-2011 flu season, 97% of all subtyped influenza-positive specimens have been influenza A (H3N2).

China

According to the China National Influenza Center, the number of influenza-positive samples is low. Both the number and percentage of influenza-positive samples have steadily decreased in Southern China between Weeks 36 and 44. In Week 44, 5% of samples tested were influenza-positive, and 79.2% of samples were positive for influenza A. Of influenza A-positive samples, 76.3% were subtyped as influenza A (H3N2).

In Northern China, the number of influenza-positive samples decreased between Weeks 43 and 44 and is low, but the percentage of samples testing positive for influenza increased steadily between Weeks 41 and 44 (15.1% in Week 44). In Week 44, 95.4% of influenza-positive samples in Northern China were positive for influenza A, and 79% of those influenza A-positive samples were subtyped as influenza A (H3N2).

Southern Hemisphere

Chile

According to the Chile Ministry of Health, the number of ILI cases and positive respiratory samples decreased steadily from Week 37 through Week 44. The majority of influenza-positive samples between Weeks 35 and 44 were influenza A (H3N2).

South Africa

According to the South Africa National Institute for Communicable Diseases (NICD), the number of influenza-positive samples detected through ILI surveillance decreased markedly from Week 33 through Week 44. Between Weeks 41 and 44, very few influenza specimens were detected through ILI surveillance; 2009 H1N1 was the predominant subtype among influenza-positive specimens.

Argentina

According to WHO’s Pan American Health Organization (PAHO), the number of positive respiratory cases has decreased steadily between Week 24 and 44, and is currently low. The majority of positive respiratory cases in 2010 were respiratory syncytial virus.

Tropical Climate Areas

Cambodia

According to WHO’s FluNet, since Week 37, the total number of influenza cases has risen steadily, reaching a weekly high in Week 44. The most prominent influenza subtypes are 2009 H1N1 and influenza A (H3N2).

Colombia

According to PAHO, the number of positive respiratory samples between Weeks 29 and 44 has steadily decreased. Since Week 37, 2009 H1N1 has been the predominant influenza subtype.

from cdc