Influenza update
20 July 2012 - Update number 164
Summary
• The influenza season is largely finished in the temperate countries of the northern hemisphere and most countries in the northern temperate zone have stopped weekly reporting or moved over to out of season surveillance schedules.
• In the tropical zone, the countries to report notable influenza activity are Bolivia, Brazil, and Honduras in the Americas; Ghana in sub-Saharan Africa; southern China, including Hong Kong Special Administrative Region, and Viet Nam in Asia.
•The influenza season has commenced in most temperate countries of the southern hemisphere. In Argentina, however, influenza remains nearly undetectable.
• Influenza A(H3N2) viruses were the most commonly reported type/sub-type in recent weeks in the Southern Hemisphere temperate region in Chile, South Africa, and Australia; however, significant numbers of influenza type B were also reported in South Africa and to a lesser extent, Australia. Very few influenza A(H1N1)pdm09 viruses have been reported with exception of Paraguay and some countries in Central and tropical South America.
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Peer-reviewed literature
Household transmission of 2009 Pandemic Influenza A(H1N1) A systematic review and meta-analysis; Lau et al
Source of data
The Global Influenza Programme monitors influenza activity worldwide and publishes an update every two weeks.
The updates are based on available epidemiological and virological data sources, including FluNet (reported by the Global Influenza Surveillance and Response System) and influenza reports from WHO Regional Offices and Member States. Completeness can vary among updates due to availability and quality of data available at the time when the update is developed.
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