Poliovirus (PV) is the causal agent of paralytic poliomyelitis, an acute disease of the central nervous system (CNS). A killed and an oral live attenuated vaccine were both developed in the 1950s (Salk 1955; Sabin and Boulger 1973), and subsequent massive vaccination campaigns resulted in near total eradication of PV from most industrialized countries: currently, wild strains are endemic in only 10 countries. However, there are two current problems concerning PV: the occurrence, in rare cases, of poliomyelitis outbreaks due to oral-vaccine-derived PV strains (Nomoto and Arita 2002); and the development of a new neuro-muscular pathology, called the post-polio syndrome, in poliomyelitis survivors long after the acute disease (Dalakas 1995).