The picornaviruses are divided into 3 genera. Entero's (see below), Rhino's (subclinical cold viruses), Aptho's (FMDV which is the exotic virus that MAFF spends most money on because of the risk of its reintroduction to the UK).

There are 4 capsid proteins with VP1 being the site for neutralising antibodies which protect. The cytopathic effect is one of overnight cell rounding and pyknosis.

The viruses infect via the upper resp tract /buccal cavity and then generalise to their target organs after a viraemia.