What is the impact of poliovirus on the central nervous system?

• A. It can lead to paralysis and loss of motor control.
• B. It cures motor deficits.
• C. It primarily causes fever with no neurological effects.
• D. It only affects peripheral nerves.

Answer: (A)

Poliovirus is capable of invading the central nervous system and damaging motor neurons. After initial infection in the gut, the virus can spread through the bloodstream to the spinal cord and brainstem, where it preferentially infects anterior horn motor neurons. Destruction of these neurons disrupts the nerves that control voluntary muscles, leading to acute flaccid paralysis with weakness and loss of motor control. Sensation is typically preserved because sensory neurons are less affected, and reflexes may be reduced or lost in the involved muscles. Involvement of the brainstem (bulbar poliomyelitis) can cause swallowing and breathing difficulties. While fever and meningitis can occur, the hallmark neurological outcome is paralysis from motor neuron destruction. It does not cure motor deficits, nor is it accurate to say it only causes fever with no neurological effects or that it affects only peripheral nerves.