This study enrolls patients who will present with acute fever and clinical signs of pharyngotonsillitis at three primary pediatric ambulances. A rapid A beta-hemolytic streptococcus (GABHS)-detection test will be performed in these patients. In one office, additional throat cultures are obtained of all patients, and blood is taken in a subgroup of 60 GABHS-positive and 60 GABHS-negative cases. In GABHS-positive patients, a second blood sample will be obtained at day 7th and day 28th, and stored until specific antibody response to GABHS will be measured.