polio

Viral infection of the central nervous system affecting nerves that activate muscles. The disease used to be known as infantile paralysis since children were most often affected. Two kinds of vaccine are available, one injected (see Salk) and one given by mouth. The Americas were declared to be polio-free by the Pan American Health Organization in 1994. In 1997 the World Health Organization (WHO) reported that causes of polio had dropped by nearly 90% since 1988 when the organization began its programme to eradicate the disease by the year 2000. Most remaining cases were in Africa and southeast Asia in early 2000.

The polio virus is a common one and its effects are mostly confined to the throat and intestine, as with influenza or a mild digestive upset. There may also be muscle stiffness in the neck and back. Paralysis is seen in about 1% of cases, and the disease is life-threatening only if the muscles of the throat and chest are affected. Cases of this kind, once entombed in an ‘iron lung’, are today maintained on a respirator.