Science / Medicine : Polio Virus Causes Later Problems

A recurrence of muscle weakness brought on by polio decades after a patient has recovered from the illness is apparently caused by the polio virus itself rather than other medical conditions, a new study has concluded.

Some doctors have suggested that aging or a deterioration of once-damaged nerve cells, and not a new attack by the polio virus itself, causes the progressive weakness, muscle pain and other problems associated with the syndrome. But a team led by Mohammad K. Sharief of the National Hospital for Neurosurgery in London reported last week in the New England Journal of Medicine that the virus was in the spinal fluid of 21 out of 36 patients suffering a new attack. The virus was not present, however, in the spinal fluid of healthy people or polio victims who did not suffer from the syndrome.

Polio, formally known as poliomyelitis, is a communicable disease in which, in severe cases, the virus attacks the spinal cord, causing swelling and excruciating pain and virtually paralyzing its victim. There is no known cure for polio but a preventive vaccine is available.