Influenza virus is a member of Orthomyxoviridiae, and responsible for influenza. The virion consists of 8 separate segments of ribonucleoproteins each containing single-stranded RNA genome coding for proteins necessary for replication and maturation. The possible recombination among segments of avian and human viruses in some mammals, and great variability of heamagglutinin antigenicity may contribute for the emergence of new epidemic strains. RNA and encoded protein sequences are played with the pictures of protein sequences and my post cards in the summer of 2004.