| Citation | Distinguished for his studies on the ecology of influenza viruses and their antigenic variation. He has with colleagues provided a wealth of information on the variety of influenza viruses in nature, and has obtained evidence for the role of avian viruses in the origin of pandemic influenza. By studies of genetic reassortment he has also established a likely mechanism for this role. In extensive collaborative studies he has made important contributions to defining the antigenic regions of influenza virus proteins and to an understanding of antigenic variation. Recently he has been committed to investigations of virus virulence, particularly in relation to seal and avian influenza. |