Picornaviruses

The Picornaviridae family is one of five families in the order Picornavirales, the others being Dicistroviridae and Iflaviridae (both infecting invertebrates), Marnaviridae (infecting algae), and Secoviridae (infecting plants) (Le Gall et al. 2008). There are currently 12 genera in the Picornaviridae, seven of which contain viruses that infect pigs: Aphthovirus, Cardiovirus, Enterovirus, Kobuvirus, Sapelovirus, Senecavirus, and Teschovirus (Table 42.1; Figure 42.1; Knowles et al. 2011). Picornaviruses for which genome sequence data have become available, but which have not yet been assigned to specific taxa, include two new groups of human picornaviruses, as well as picornaviruses of bats, seals, turkeys, wild birds, reptiles, and fish. None of these are known to infect pigs (Knowles et al. 2011). Picornaviruses infect vertebrate hosts and enter host cells using receptor-mediated endocytosis or possibly, the enteroviruses, by direct entry of RNA across the plasma membrane following changes induced in the virus particle by receptor binding. They replicate in the cytoplasm of infected cells.