The novel flu virus appears to be a mutation of the Spanish Flu virus of 1918, which was H1N1. But it's different from the "swine flu" of that year: this new virus is a reassortment of genes from people, pigs and poultry.
這次的新流感病毒，應是由同屬 H1N1 的 1918 年西班牙大流感病毒變異而來，但和當年的 H1N1 不同，此次的病毒，是由人、豬和禽鳥的病毒基因組合而成的一株新病毒。