There is a high degree of serological cross reactivity between the 72 members. Relatively resistant to extremes of pH and temperature, and to lipid solvents and detergents. 3 types can be distinguished by antigenic properties. Local multiplication also takes place in the gut mucosa and regional lymph nodes. Thereafter a viraemia follows, and the patient may experience a fever about a week after exposure.
Most infections are asymptomatic, although in some there is a minor transient febrile illness.
The patient may experience degrees of headache, fever, meningism, aseptic meningitis and muscle pains, and finally muscle paralysis, usually asymmetrical. No true long term carrier status occurs. The host's antibody response begins soon after the viraemia. Good solid lifelong immunity results to the specific strain of poliovirus, but subsequent infection with other strains may still occur. Multiple specimens over several days improves chances of recovery of the virus.