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World Map showing countries confirmed and suspected of being the origin of influenza pandemics. Blue – The origin of the 1918 Spanish is still unclear, although various papers suggest the United States (New York) or France as the origin; yellow – China the origin of the 1957 Asian flu pandemic; Hong Kong, the origin of the 1968 Hong Kong pandemic; red – Russia, the origin of the 1889 and 1977 Russian flu pandemics; green – Mexico, the origin of the 2009 Swine flu pandemic.
