An epidemic of group A, type 4 streptococcal carriers among school children and their desk location at school.

During a follow-up study of pharyngeal carrier of beta-hemolytic streptococci among school children in three classes (ages 8-9) in Sapporo City, an epidemic of group A, T4 streptococcal carrier was observed. The epidemic started in February 1978 in class II (35 pupils) and spread to class I (36 pupils) in May. Class III developed only three carriers during the course. Information on the desk location of those children at school and those on some host factors or on several environmental factors were collected. Monthly sociometric tests were performed on those pupils and corresponding sociograms were constructed. New T4 carrier rate by month was calculated for class I and class II by pupil's desk location (adjacent vs. remote) or by degree of pupil's friendship (best friends vs. others, based on the sociogram). More new carriers were detected from susceptibles adjacent to previous carriers then from those remote to them. There was no significant difference with carrier rate between best friends and others. The T4 carriers did not significantly differ from the remaining noncarriers in terms of status with host or environmental factors examined.