What Are the Symptoms of Polio?
Muscle aches, fever, and (in rare cases) paralysis are some of the possible symptoms of polio. However, it's important to note that up to 95 percent of people infected with the poliovirus will have no symptoms. In severe cases, polio symptoms can lead to complications, such as fluid in the lungs, high blood pressure, and pneumonia.
When a person becomes infected with poliovirus, the virus begins to multiply within the cells that line the back of the throat, nose, and intestines. Symptoms usually appear 7 to 14 days after a person becomes infected with the poliovirus. This period between polio transmission and the start of polio symptoms is called the "polio incubation period." The incubation period for polio can be as short as 4 days or as long as 35 days.
(Click Polio Incubation Period for more information about the incubation period for polio.)
Up to 95 percent of people who are infected with poliovirus will have no symptoms. However, people who are infected and do not have polio symptoms can still spread the poliovirus and cause others to develop polio.
If a person does develop symptoms of polio, the symptoms can be categorized into one of three groups, which include:
- Minor polio symptoms (also known as abortive poliomyelitis)
- Aseptic meningitis
- Paralytic poliomyelitis.
About 4 to 8 percent of people who are infected with the poliovirus will develop minor polio symptoms. These minor symptoms can include:
People who develop minor polio symptoms develop no paralysis or other serious symptoms. These symptoms last for two to three days with complete recovery.