FLU. Orthomyxoviridae. Eight segmented pieces of RNA, a structure that permits the introduction of new RNA. This is called genetic reassortment. This is called antigenic shift.
Three strains: (always A-A-B) this year:
-A-California h1n1-”like” virus
-A-Perth h3n2 ”like” virus
Every year the strains are selected based on worldwide surveillance for most active strains– a little guess-work involved
Babies, pregnant women