(added on 2013/02/19)
What next for Hong Kong? 緊接下來的是什麼?
Influenza is caused by the influenza virus. The influenza virus is not a single virus but rather the name for a range of virus subtypes. Subtypes may undergo mutations and could take on new forms. Currently the 3 main subtypes in circulation around the world are Influenza A H3N2, H1N1 (previously "swine flu") and Influenza B. These viruses take turn to cause influenza seasons. In the United States the influenza season has started early this season, with some places like the New York State declaring public health emergency in January 2013. H3N2 is the main cause of infections in the current season, which seems to have peaked recently. The maps show the distribution of the three viruses between the last 2 weeks of December 2012 and the first two weeks of January 2013, expressed as the number of positive cases for the specific virus in processed specimens. The higher rates of H3N2 remain localized to US and Canada. Elsewhere a mixed pattern involving H1N1, H3N2 and B in varying proportion is seen. Data for the map were obtained from World Health Organization's FluNet (http://apps.who.int/globalatlas/dataQuery/default.asp). In Hong Kong, the influenza season has started in January 2013 before the Chinese New Year. Interestingly respiratory symptoms have become more common since December 2012, as revealed in the community surveillance project EcSS (www.EcSS.hk).