In 1972 more than 20% of boys admitted to a closed community (Junior Detention Centre) developed acute tonsillitis and group-A streptococci were isolated from more than 40% of all boys at some time during their stay of two months. The most common serotype was M-type 5, which has frequently been associated with rheumatic fever in other epidemics; four cases of rheumatic fever occurred between 1972 and 1977. Various methods were tried to eliminate the infection, but only full penicillin prophylaxis (0·25 g oral penicillin 4 times a day for 10 days) to all boys on entry appeared to be effective.
In a sample of cases of acute tonsillitis, group-A haemolytic streptococci were isolated from 31·7% by the use of dry swabs or unenriched transport medium, but with enrichment medium duplicate swabs, 77·0% yielded positive results. We question the current practice in some laboratories of reporting positive cultures only when more than ten colonies of β-haemolytic streptococci are present. In this survey viruses did not appear to be an important cause of acute tonsillitis.
High titres of streptococcal antibodies (antistreptolysin O, anti-desoxyribonuclease B and anti-M associated protein) were found, not only in cases and carriers, but in boys on entry to the centre. This supports epidemiological evidence that adolescent boys on entry to the centre. This supports epidemiological evidence that adolescent boys are particularly prone to streptococcal throat infections.