A molecular surface model of poliovirus type I with bound receptors, one of three serotypes of polioviruses responsible for poliomyelitis (a.k.a Polio). Poliovirus is a single-stranded positive-sense RNA virus in a protein capsid, which colonizes the gastrointestinal tract of its host and is transmitted via the fecal-oral route. Aside from being able to survive in highly acidic conditions, the virus can replicate quickly and spread throughout the body in a very short amount of time. Though most cases of poliomyelitis are asymptomatic, if the virus enters the central nervous system, it begins destroying motor neurons leading to inflammation of the spinal cord, causing muscle weakness or possible paralysis.