Strep throat is contagious. However, most people do not get group A strep infections from casual contact with others. Instead, the bacteria are transmitted through contact with infected throat mucus, nasal discharge, or saliva.
This can happen when an infected person sneezes or coughs, and infected droplets spray into the air. The infected mucus can land in another person's nose, throat, or eyes, and enter their body.
Strep bacteria can also spread by touching a surface or object that has infectious fluids on it. When the person then touches their mouth, nose, or eyes, the bacteria can be spread. It takes about two to four days after contact with the bacteria for a person to develop strep throat symptoms.
(Click Strep Throat Transmission for more information.)
There is not one particular sign or symptom that specifically points to strep throat. So, to help narrow down whether a throat infection is the result of strep, healthcare providers ask about specific symptoms.
A person with strep throat usually has at least two out of four of these signs or symptoms:
- A red and painful throat that begins suddenly
- A fever above 101ºF (38.3ºC)
- Red and enlarged tonsils -- there may also be white patches of pus on the tonsils or in the throat
- Tender or swollen lymph glands in the neck.
A cough and/or runny nose do not usually occur in someone with strep throat. These symptoms are more common with a sore throat caused by a virus. It is also uncommon for someone with strep throat to have a sore throat for more than one week.
(Click Strep Throat Symptoms for more information, including a list of symptoms that are typical in infants and children.)