According to the Centers for Disease Control and Prevention, children suffer six to eight colds a year, causing about 22 million lost days of school. A cold is caused by one of more than 200 different viruses. The most common cause is a group of viruses known as the rhinoviruses, which are most active in the fall, spring, and summer.
Some other types of viruses causing cold symptoms include adenovirus, respiratory syncytial virus, coxsackievirus, and parainfluenza virus. Colds generally cause runny or stuffy nose, sore throat, coughing, sneezing, and body aches. For most people, the symptoms run their course in about a week. In some patients, especially those with weakened immune systems, a secondary bacterial infection sets in, causing high fever, swollen glands, sinus infection, or a more serious respiratory infection. Colds are spread through contact with contaminated respiratory droplets. The germs can be spread through the air or by touching a contaminated surface. A person becomes infected touching the contaminated surface and rubbing his eyes or nose.