👉 Poliovirus is a virus that causes polio, a highly contagious disease primarily affecting children between the ages of 6 months and 5 years old. It spreads through contaminated respiratory droplets from an infected person's mouth or coughing, which can infect other people in close contact with them. Polio affects the nervous system by damaging the spinal cord and causing paralysis, leaving individuals unable to walk and breathe normally.