http://www3.niaid.nih.gov/healthscience/healthtopics/streptococcal/default.htm
National Institute of Allergy and Infectious Diseases, National Institutes of Health
Group A streptococcal (strep) infections are caused by group A streptococcus, a bacterium responsible for a variety of health problems. This fact sheet discusses strep infections that can range from a mild skin infection or sore throat to life-threatening conditions, including impetigo, scarlet fever, and toxic shock syndrome.