Group A streptococcal (GAS) infection is a group of bacteria which causes infections in the throat and skin.
Scarlet fever is a contagious infection caused by Group A streptococcal infection that mostly affects young children. It's easily treated with antibiotics.
Sometimes severe GAS disease may occur when bacteria get into parts of the body where bacteria are usually not found, such as the blood, muscles or the lungs. These infections are known as invasive Group A Streptococcal disease (iGAS) and may include serious conditions, such as toxic shock syndrome.