Note: Individuals infected with the poliovirus are often asymptomatic. In approximately 25% of cases, polio presents as a mild to moderate illness marked by headache, fever, sore throat, vomiting, diarrhea, and fatigue. Polio affects the central nervous system only infrequently with inflammation and sometimes destruction of the motor neurons in the gray matter of the spinal cord and brain stem. Central nervous system involvement results in temporary or permanent muscle weakness or motor paralysis especially of the limbs and typically the legs. Polio may become life-threatening when paralysis affects the muscles involved in breathing and swallowing.
Mary Beth Norton et al.Betsy McKaycalled also infantile paralysis, poliomyelitis
see post-polio syndromeExamples of polio in a Sentence
David Morgan
july 11, CBS News, 11 July 2025
The news made the front page of the Times, albeit below the fold (right next to a story about the launch of the field trials for Jonas Salk’s polio vaccine).
—Bill McKibben, New Yorker, 9 July 2025
Jerry who sat in front of me in fifth grade got polio.
—Chicago Tribune, 3 July 2025
The American public enjoyed significant milestones in public health, including the introduction of Jonas Salk’s polio vaccine in the 1950s.
—Jessica George, JSTOR Daily, 25 June 2025
See All Example Sentences for polio
Cite this Entry
“Polio.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/polio. Accessed 20 Jul. 2025.
Copy CitationKids Definition
polio
noun
Medical Definition
polio
noun
Note: Individuals infected with the poliovirus are often asymptomatic. In approximately 25% of cases, polio presents as a mild to moderate illness marked by headache, fever, sore throat, vomiting, diarrhea, and fatigue. Polio affects the central nervous system only infrequently with inflammation and sometimes destruction of the motor neurons in the gray matter of the spinal cord and brain stem. Central nervous system involvement results in temporary or permanent muscle weakness or flaccid paralysis of muscles especially of the limbs and typically the legs. Polio may become life-threatening when paralysis affects the muscles involved in breathing and swallowing.
People WeeklyEvan Johnson, The Addison County (Vermont) Independentcalled also infantile paralysis, poliomyelitis
see post-polio syndrome
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