About Strep Throat: Causes
Streptococci are everywhere. About 20% of us have them on our skin, and 10% of children have them in their throats at any given time. They don't always cause disease; however, streptococci are infectious. They are passed around in the same way as cold viruses, by coughing, sneezing, or getting mucus or saliva on the hand, then touching other people. They are less contagious than a cold virus, however.
Smoking and heavy drinking, which can damage the lining of the throat, increase the risk of bacterial infection. Frequent heartburn can also encourage infection if the digestive acids rise as high as the throat. People with weak immune systems from HIV/AIDS, diabetes, cancer treatment, or corticosteroid drug use are also at higher risk.
The best place to catch strep throat is in a hospital. Not only are there more vulnerable people around, but hospital workers and inpatients are also more likely than average to carry group A strep.