Assessing the potential pandemic risk of recent avian influenza viruses

Abstract

Highly pathogenic avian influenza viruses (HPAI) of the influenza A, H5N1 subtype (the H refers to the type of haemagglutinin and the N refers to the type of neuraminidase) have circulated in various parts of Asia since 1996, infecting millions of birds and, occasionally, humans [1, 2]. Since 2014, a subclade of these viruses has further reassorted into what have been referred to as H5Nx viruses, owing to the variety of N genes that have successfully reassorted with this H5 haemagglutinin. These reassortants have spread in an unprecedented fashion over 60 countries [3], with H5N8 and H5N2 outbreaks in Europe and North America [4, 5] having caused major economic losses in the poultry industry..