When influenza viruses from different species infect pigs, the viruses can reassort (i.e. swap genes) and new viruses that are a mix of swine, human and/or avian influenza viruses can emerge.

• 当不同种来源的流感病毒同时感染时，病毒之间就会重新“洗牌”(交换基因)，从而产生一种新的“禽人猪”混合病毒。