The most common contagious disease in the world is the common cold. Colds are actually infections of the mucous membranes of your nose and throat, but sometimes they spread to your air passages and lungs.
The cold germs, or viruses, that cause these infections and make you cough or sneeze travel through the outside air inside tiny droplets of moisture. Doctors believe that you can “catch” a cold if you breathe in these virus droplets expelled by someone who is already sick.
The strange thing about these viruses is that they are probably in your throat most of the time. However, they simply do not attack your body until your resistance is lowered by being chilled, overheated, or extremely tired.
A cold takes from one to three days to develop and it does so in three stages. The first is the “dry” stage, during which your nose feels dry and swollen, your throat may tickle, and your eyes may water. In the second stage, your nose begins to run. And finally, in the third stage, you may develop a fever and a cough.
There are more than 200 different viruses that can cause colds!