What virus causes polio?
Poliovirus, isolated in 1909 by Karl Landsteiner and Erwin Popper, is a small RNA enterovirus composed of an RNA genome enclosed in a non-enveloped capsid. The poliovirus genome is limited and only large enough to encode about 10 genes which encode the small number of viral proteins critical for the virus to invade and replicate within human cells. There are three separate serotypes of polio, PV1, PV2, and PV3; each with a slightly different capsid protein. PV1 is the most common form encountered in nature, however all three forms are extremely infectious. Poliovirus is strictly a human pathogen, and it cannot naturally infect other species.
