26 October 2012 - Update number 171
• Many countries of the Northern Hemisphere temperate region are reporting increasing sporadic detections of influenza viruses but numbers are still low and none have crossed their seasonal threshold. No recent cases of the swine origin influenza A(H3N2)v virus have been reported since the start of the school season in the United States of America.
• A few countries in tropical areas have experienced active transmission on influenza in recent weeks. Most notable are Nicaragua and Costa Rica in the Americas, where influenza type B has been the most commonly detected virus in recent weeks, and Sri Lanka, Nepal, and Thailand in Asia, where influenza A(H1N1)pdm09 has been slightly more common than influenza type B.
• In Sub-Saharan Africa, countries of West (Senegal and Cote d’Ivoire) and Central African (Cameroon) have reported increasing detections of influenza virus, primarily A(H3N2).
•Influenza activity in most areas of temperate countries of the Southern Hemisphere are now at inter-seasonal levels.
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.