A follow-up study on epidemic infections of Group A streptococci in a small community.

The throat carrier rates of Group A streptococci and the antibody titers to 3 antigens of Group A streptococci, i.e., antistreptolysin O (ASO), antideoxyribonuclease B (ADN-B) and antistreptococcal polysaccharide (ASP) were followed up from October, 1980 through November, 1981 for the children living in a religious organization in Kyoto, where epidemic infections of Group A streptococci had occurred from August to October, 1980. The recovery rate of Group A streptococci from the throat increased throughout the present study period, and the high carrier rate of Group A streptococci was maintained especially for first 8 months after the epidemic infection. Type 4 was present throughout the entire 13-month period. Although the ASO and ADN-B titers, both of which had initially risen, decreased during the present study period, the ASP levels peaked after about 4-8 months and decreased after 13 months. None of the children showed evidence of rheumatic fever with continuous observation.