What is strep pharyngitis?

Strep pharyngitis is a highly contagious bacterial infection caused by a Group A Strep (GAS) bacteria. It is sometimes referred to as tonsillitis or strep throat. Group A streptococcus is a bacterium often found in the throat and on the skin. People may carry group A streptococci in the throat or on the skin and have no symptoms of illness. Most GAS infections are relatively mild illnesses such as "strep throat," or impetigo. On rare occasions, these bacteria can cause other severe and even life-threatening diseases.