Group A streptococcal infection epidemiology and demographics

Overview
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.

Epidemiology and Demographics
Approximately 9,000 cases of invasive disease (3.2/100,000 population) occurred in 2002; STSS and NF each accounted for approximately 6% of cases. Over 10 million noninvasive GAS infections (primarily throat and skin infections) occur annually.

National passive surveillance for invasive infection and STSS since 1995. Active, population-based surveillance is conducted in 10 states in the Emerging Infection Program (total population: 31.5 million).

Worldwide, rates of invasive disease, STSS and NF increased from the mid-1980s to early 1990s. Rates of invasive disease have been stable over the last 5 years in the United States. Increases in the rate and severity of disease associated with increases in prevalence of M-1 and M-3 serotypes (emm types 1 and 3). Resistance to erythromycin has increased worldwide.