现在有多少种猪流感病毒？中英文对照阅读
Swine FluWhat is Swine Influenza?
Swine Influenza (swine flu) is a respiratory disease of pigs caused by type A influenza virus that regularly causes outbreaks of influenza in pigs. Swine flu viruses cause high levels of illness and low death rates in pigs. Swine influenza viruses may circulate among swine throughout the year, but most outbreaks occur during the late fall and winter months similar to outbreaks in humans. The classical swine flu virus (an influenza type A H1N1 virus) was first isolated from a pig in 1930.
什么是猪流感？
猪流感(Swine Influenza, swine flu)是猪的一种呼吸道疾病，它的病原是一种能造成周期性爆发的A型流感病毒。猪流感病毒的致病率很高，但猪的死亡率低。猪流感病毒在全年都有可能传播，但大部分会在深秋和冬季月份爆发，这一点与人流感类似。典型的猪流感病毒(A型H1N1病毒)于1930年第一次从猪身上分离出来。
How many swine flu viruses are there?
Like all influenza viruses, swine flu viruses change constantly. Pigs can be infected by avian influenza and human influenza viruses as well as swine influenza viruses. 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. Over the years, different variations of swine flu viruses have emerged. At this time, there are four main influenza type A virus subtypes that have been isolated in pigs: H1N1, H1N2, H3N2, and H3N1. However, most of the recently isolated influenza viruses from pigs have been H1N1 viruses.
现在有多少种猪流感病毒？
就像所有的流感病毒一样，猪流感病毒也在不停地变化当中。禽流感，人流感以及猪流感病毒都会对猪造成感染；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。随着时间的推移，也出现了猪流感病毒的多种变种：现在人们从猪身上分离出了4种主要的A型流感病毒亚型： H1N1, H1N2, H3N2, H3N1。但最近从猪分离出来的流感病毒大部分都是H1N1型病毒。