Understanding Picornaviruses and Polio

Remember polio? The virus that once paralyzed thousands of children every year?

That devastating disease came from one of the most fascinating — and sneakiest — families

of viruses out there: the picornaviruses. Picornaviruses are Class IV viruses in the Baltimore

scheme — meaning they carry positive-sense single-stranded RNA, which can act immediately

as mRNA once inside a host cell. These are naked virions, so they don’t have

an envelope to fuse with the cell membrane. Instead, they’re endocytosed — literally swallowed

up by the host cell. They’re split into two main groups: enteroviruses, which infect the

gut, and rhinoviruses, which cause the common cold. Their capsid is