Signs and Symptoms
Polio is a viral illness that, in about 95% of cases, actually produces no symptoms at all (called asymptomatic polio). In the 4% to 8% of cases in which there are symptoms (called symptomatic polio), the illness appears in three forms:
1.a mild form called abortive polio (most people with this type may not even suspect they have it because their sickness is limited to mild flu-like symptoms such as mild upper respiratory infection, diarrhea, fever, sore throat, and a general feeling of being ill)
2.a more serious form associated with aseptic meningitis called nonparalytic polio (1%-5% show neurological symptoms such as sensitivity to light and neck stiffness)
3.a severe, debilitating form called paralytic polio (this occurs in 0.1%-2% of cases)