Poliovirus is highly communicable. The time between infection and onset of
paralysis (incubation period) is 10 -21 days ( range 4 -35 days). Transmission
is primarily person to person via the faecaloral route, i.e. the poliovirus
multiplies in the intestines and is spread through the faeces. The virus
is intermittently excreted to one month or more after infection. Communicability
of infected children is highest just prior to the onset of paralysis and
during the first two weeks after paralysis occurs. The virus spreads rapidly
and transmission is usually widespread by the time of paralysis onset.
There is no long term carrier state in normal children.
