FACTS: Although paralytic diseases have existed for ages, polio was the scourge of the early part of the 20th century. Ironically, up to 99% of the time, polio is asymptomatic, abortive, or non-paralytic, producing no symptoms, flu-like symptoms, or light-sensitivity and neck-stiffness. However, the petrifying consequences of paralytic polio (often spread during the summer months) were withered legs, paralyzed chest muscles, and in the worst cases, immersion into an “iron lung” breathing-machine. Though the illness passed after a few weeks, the paralytic effects could persist.
One theory suggests that modern sanitation may have actually helped trigger the epidemic of paralytic polio. Improved sewage systems greatly reduced incidents of the infant polio that confers immunity but tends to be non-paralytic. As polio was contracted in historically large numbers later in life, incidents of paralytic polio greatly increased.