Equine influenza virus (EIV) is a major and highly contagious respiratory virus responsible for outbreaks of equine influenza (EI) worldwide. Nowadays, only EIV of the Clade I and Clade II Florida sub lineage are circulating amongst equids. While the virus continuously evolves and alters its morphology to escape the immune system of the host, it is very important to determine how the structure of the proteins responsible for he induction of a solid immunity change over times.
