Group A streptococcal bacteraemias in Denmark 1987-89.

A retrospective study of laboratory-verified cases of Group A Streptococcal bacteraemias in Denmark was conducted for the period 1987-1989 after a sudden increase occurred during the winter 1988-1989. The aim of the study was to describe the epidemiology in the period and to compare cases during the outbreak period with cases in a period with a baseline risk. Based on isolates, a total of 242 cases in 240 patients were included in the study and information on previous health of the patients, source of infection (community-acquired or nosocomial) and outcome were obtained from hospital records. During the epidemic period the total incidence increased three-fold. The frequency of type 1 increased from 1 in 5 to 1 in 2. The number of previously healthy individuals falling ill with type 1 increased 25-fold. The relative increase was higher among patients with community-acquired infection than among patients with nosocomial infection. The lethality rate was 48% during the epidemic in which 38% of the cases occurred. As early diagnosis and treatment are the two most important measures to prevent serious outcome, effectiveness and timeliness of surveillance systems are of extreme importance.