Provocation poliomyelitis and entry of poliovirus to the CNS.

It is proposed that entry to the CNS by poliovirus occurs from multiple sites which are seeded during viremia. At each site, an inflammatory reaction allows entry to peripheral nerves. Differences in incubation times are related to the length of nerve to be followed. Virus reaches the CNS sequentially but does not in natural poliomyelitis spread within the CNS. Provoking agents are identified as immunogenic and their action explained. Details of paralysis among Cutter vaccinees are explained by this model, as well as the effects of multiple inoculation in monkeys. Clinical symptoms in the preparalytic stage of poliomyelitis are consistent with this model.