A contagious disease is an illness that can be passed from one person to another easily. Just like how sharing toys and snacks with friends can spread happiness, sharing germs can spread sickness. Germs are tiny little things that can make people very sick if they get inside a person's body.
Some contagious diseases like the flu or the common cold can be spread just by coughing, sneezing, or touching things that have been touched by someone who is sick. Other contagious diseases like chickenpox or measles are spread by tiny little things called viruses that are in the air or on surfaces.
When someone is sick with a contagious disease, they need to stay away from other people so they don't spread their germs to others. Doctors might also give them medicine or a special vaccine to help their body fight off the germs so they can get better faster.
It's important to remember to wash your hands often and cover your mouth and nose when you cough or sneeze so you don't spread your germs to others. By staying healthy, we can help stop the spread of contagious diseases so everyone can be happy and healthy!