Tue 9 February 2010
The vaccines > DTaP/IPV/Hib > The diseases > Polio
Poliomyelitis (polio) is an acute illness caused by polio virus.
It is a highly infectious disease spread mainly through close contact with an infected person.
The virus is usually passed on through the faecal-oral route (which usually means water contaminated with faeces).
The virus is also found in the throat of an infected person so it can be spread through saliva too.
The polio virus enters the body through the nose or mouth and infection starts in the gut. It then enters the blood stream and is carried to other parts of the body.
If the virus reaches the central nervous system it can cause paralysis.
The incubation period of the polio virus ranges from 3 to 21 days. Cases are highly infectious for 7 to 10 days before symptoms appear, but the virus may be passed on in faeces for up to 6 weeks or longer.
There are three strains of polio virus - types I, II and III. Type II has already been eradicated from the world.