Streptococcus is a group of bacteria which can infect humans, producing a range of mild to deadly illnesses, for instance during World War II, they caused toxic shock and destroyed muscle and flesh. Generally, Streptococcus can be easily controlled with penicillin.
The Streptococcus group of bacteria is divided into three groups: alpha-hemolytic, beta-hemolytic and no-hemolytic. These groups are broken down further by letter grades A to V, for example, gram-positive, beta-hemolytic group A Streptococcus, also called Streptococcus pyogenes or group A strep (GAS). Pyogenes infections cause mild to severe illness, including: pharyngitis; scarlet fever (rash); impetigo; cellulitis; erysipelas (skin infection); necrotizing fasciitis; myositis (inflammation of muscle tissue); toxic shock syndrome; rheumatic fever; acute glomerulonephritis. Group B, aka Streptococcus agalactiae, may cause severe diseases such as neonatal pneumonia and sepsis, meningitis, vaginitis and endocarditis.
There are 80 strains of Streptococcus, of which a few predominate in the population at any one time. In 1994, about 12 people died of a streptococcus invasion, and severe infections appeared around the world.
Incidence in the USA is around 10,000 to 15,000 non-fatal cases per year, and the pattern of incidence is thought to be cyclic, with peaks every few years. About one third of all women will be infected by this bacterium at some time in their lifetime, but often they have no symptoms. The group B Streptococcus bacterium is a leading cause of death among newborn infants in the USA. It infects around 8,000 babies each year, killing about 500 and leaving the rest with severe brain damage from meningitis.