Abstract
1. Two successive epidemics of streptococcus infection occurred in nursery schools and kindergartens of 0 town in Toyama prefecture during the latter half of 1980. The first outbreak, to June to July, total number of patients being 77, was among children of A nursery school and B kindergarten in 0 primary school zone of this town. The second one, from September to November, total number of patients being 21, occurred among children of C and D nursery schools and E kindergarten in K primary school zone adjacent to the district where the first epidemic occurred. The causative agent of the former epidemic was type M12 group A streptocococcus resistant to erythromycin, and of the latter, the same serotype but sensitivie to erythromycin. During the second outbreak, sporadic cases of streptococcus infection caused by type B3264 and scarlet fever caused by type M1 were also detected.
2. Examinations on background populations with regard to carrier states of streptococcus revealed that there were significant number of healthy. carriers of the same serotype and antibiotic sensitivity as the epidemic strains in accordance with each peak of epidemics. However, carriers of the epidemic serotype gradually decreased among children in both 0 and K school zones. Instead, type M1 carriers increased in both school zones in December the same year, when two sporadic cases of scarlet fever due to type Ml were reported.
3. Follow-up examinations conducted next year (1981) revealed that there were few carriers of the epidemic serotype among children in both 0 and K school zones with exception of one class in C nursery school, where several carriers of the epidemic serotype (A M12 sensitive to erythromycin) were found in July and October. A few carriers of type M1, however, were still found among children in both school zones.
