The group A streptococcus bacterium (Streptococcus pyogenes, or GAS) is a form of Streptococcus bacteria responsible for most cases of streptococcal illness. Other types (B, C, D, and G) may also cause infection.

  1. If you have strep throat infection, you will have a red and painful sore throat and may have white patches on your tonsils.
  2. You also may have swollen lymph nodes in your neck, run a fever, and have a headache.
  3. Nausea, vomiting, and abdominal pain can occur but are more common in children than in adults.