poliovirusc : consequences

• scattered nerve cells destroyed ? => no visible sign of muscle weakness

• motor nerves that innervate muscle ? => flaccid paralysis :

• • • Spinal poliomyelitis : weakness limited to muscles innervated by motor neurons in spinal cord
    • Bulbar poliomyelitis : cranial nerve nuclei or medullary centers are involved (may result in swallowing dysfunction and cardiac or respiratory failure