How you get poliovirus: the stool of an infected person
contaminates your food or water.
Symptoms: After 4-35 days, illness begins with fever,
headaches, vomiting, constipation, stiffness in the
neck, and pain in the limbs. Once established
in the intestines, poliovirus can enter the blood stream
and invade the central nervous system. As it spreads, the virus
destroys the nerve cells (motor neurons) which activate muscles,
and the affected muscles no longer function.
The industrialized nations suffered large polio epidemics
in the 1940s and 1950s, and many schools and communities
were paralyzed by fear of the crippling disease. Once vaccines were
developed, however, the incidence of polio has dropped, and a concerted
effort to eradicate the disease globally is underway.