Because the nevrvous system is the the control system of our body that means when this is harmed or infected it may cause paralysis or other diseases related to bodily movements.
3 4 3
Nervous system the main processing center of the body, it controls all the activities you do, it connects all your body parts and transmits signals from one part to another,if there is any damage of your nervous system, it affects the other, since they are connected so the brain can't transmitted signal because of the failure.