9. Polio Poliomyelitis, often called polio or infantile paralysis, is an acute viral infectious disease spread from person to person, primarily via the fecal-oral route.
The term derives from the Greek polio , meaning “grey”, myelon , “spinal cord”, and -itis, which denotes inflammation.
Although roughly 90% of polio infections are asymptomatic, affected individuals can exhibit a range of symptoms if the virus enters the blood stream.
In less than 1% of polio cases the virus enters the central nervous system, preferentially infecting and destroying motor neurons, leading to muscle weakness and acute flaccid paralysis.