Polio is an infectious virus. It selectively destroys the spinal cord's motor nerve cells, which control muscles. Although the virus causes structural muscle weakness, it leaves sensation and motor control intact. As a result, polio victims can compensate for muscle deterioration buy using healthy muscles.
After 30 to 40 years of such compensation, pain, fatigue and weakness return. Healthy cells have taken over the work of diseased ones and, through years of strain, are now destroyed themselves. Chronic mechanical strain uses up tissue reserves in ligaments, joint surfaces and/or muscles during this time span.
The increase of patients reporting recurrences reflects combined results of large epidemics of the '40s and '50s, according to Dr. Jacquelin Perry, director of the polio clinic at Rancho Los Amigos Hospital in Downey.
Dr. Lauro Halstead, of Houston's Institute of Rehabilitation and Research and himself a polio survivor, says, "It's almost like a bomb ticking away."
Though they were told to exercise conscientiously the first time around, patients are advised to take it easy now in order to slow down the deterioration. Only pain and fatigue can be treated.
There is no cure for the non-fatal, slow-progressing condition.