Strep throat is caused by Group A Streptococcus bacteria. It is the most common bacterial infection of the throat.
Pharyngitis - streptococcal; Streptococcal pharyngitis
Causes, incidence, and risk factors
Strep throat is most common in children between age 5 and 15, although anyone can get it.
Strep throat is spread by person-to-person contact with nasal secretions or saliva. It commonly spreads among family or household members.