Group A Streptococcus (GAS) can cause infections due to a type of bacteria that are often found in people's throat and on their skin. People may carry GAS in these parts of the body and have no symptoms of illness.
Most GAS infections are relatively mild illnesses such as "strep throat," or impetigo. However; occasionally these bacteria can cause severe and even life-threatening diseases.
These severe GAS infections may occur when the bacteria gets into parts of the body where it is usually are not found. These areas include the blood, muscles, or the lungs. These infections are termed "invasive GAS disease."
Two of the most severe, but least common, forms of invasive GAS disease are necrotizing fasciitis and streptococcal toxic shock syndrome. Necrotizing fasciitis, also known as flesh-eating bacteria, is a rapidly progressive disease which destroys muscles, fat, and skin tissue.
Streptococcal toxic shock syndrome (STSS) is yet another condition, with STSS people can experience a rapid drop in blood pressure and organs such as the kidney, liver, or lungs may fail. STSS is not the same as the "toxic shock syndrome" due to the bacteria Staphylococcus aureus which has been associated with tampon usage. While 10%-15% of patients with invasive GAS disease die from their infection, approximately 25% of patients with necrotizing fasciitis and more than 35% with STSS die.
GAS is typically spread through direct contact with mucus from the nose or throat of persons who are infected or through contact with infected wounds or sores on the skin. Ill persons, such as those who have strep throat or skin infections, are most likely to spread the infection. People who carry the bacteria, but have no symptoms, are much less contagious.