1918年爆发流感大流行，在数个月内造成全球大约5000万人死亡，而今，科学家们发现，若改变病毒体的外壳蛋白结构，竟能延缓病毒的扩散，这项发现也许能作为科学家预防下一次流感的警示。
美国疾病管制及预防中心(Centers for Disease and Prevention)的科学家培养了一批1918年的H1N1流感病毒，但他们将病毒外壳上hemagglutinin蛋白的两个胺基酸改变，再将这些病毒滴到雪貂的鼻子(利用雪貂作为宿主是因为它的感染和传播方式与人类很相似)。受到H1N1病毒感染的雪貂仍会生病或死亡，但很明显的，牠们并不会感染隔壁笼的雪貂，这项发现发表于2月2日的Science期刊。
到底为什么会这样呢？一般情况下，病毒是由咳嗽或打喷嚏的飞沫所传播，而被改过的H1N1病毒感染的雪貂，竟不会打喷嚏。研究人员认为当新的流感病毒造成大流行时，会由病毒外壳上的hemagglutinin蛋白附着到人类的鼻子或气管的黏膜细胞上，只要打喷嚏病毒就得以传播。
虽然H5N1病毒在全世界仍造成至少164人死亡，但令人感到欣慰的是，此病毒比较喜欢附着在禽类的肠道内，且目前并无法以人传人的方式传播。美国范德保大学(Vanderbilt University)的流行病学专家William Schaffner博士说：「研究流感病毒是一个很重要又精细的任务。」研究人员的下一步将要研究改变H5N1的hemagglutinin蛋白质结构，以观察H5N1病毒在hemagglutinin被改变后是否与H1N1病毒有一样的结果。
部分英文原文：
A Two-Amino Acid Change in the Hemagglutinin of the 1918 Influenza Virus Abolishes Transmission
Terrence M. Tumpey,1* Taronna R. Maines,1 Neal Van Hoeven,1 Laurel Glaser,2 Alicia Solórzano,2 Claudia Pappas,1,2 Nancy J. Cox,1 David E. Swayne,3 Peter Palese,2 Jacqueline M. Katz,1 Adolfo García-Sastre2
The 1918 influenza pandemic was a catastrophic series of virus outbreaks that spread across the globe. Here, we show that only a modest change in the 1918 influenza hemagglutinin receptor binding site alters the transmissibility of this pandemic virus. Two amino acid mutations that cause a switch in receptor binding preference from the human -2,6 to the avian -2,3 sialic acid resulted in a virus incapable of respiratory droplet transmission between ferrets but that maintained its lethality and replication efficiency in the upper respiratory tract. Furthermore, poor transmission of a 1918 virus with dual -2,6 and -2,3 specificity suggests that a predominant human -2,6 sialic acid binding preference is essential for optimal transmission of this pandemic virus. These findings confirm an essential role of hemagglutinin receptor specificity for the transmission of influenza viruses among mammals.
1 Influenza Branch, Mailstop G-16, Division of Viral and Ricksettial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30333, USA.
2 Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029, USA.
3 Southeast Poultry Research Laboratory, Agricultural Research Laboratory, U.S. Department of Agriculture, 934 College Station Road, Athens, GA 30606, USA.
