Antistreptolysin O titres amongst children in a rural area of Ceylon.

Antistreptolysin O titres in the sera of children in a rural population of Ceylon were determined, to establish the upper limit of the normal ASO titres in non-rheumatic children, and to compare these ASO titres with results of surveys done in other countries.Swabs were taken from throats and ulcers of the children examined and cultured specifically for group A haemolytic streptoccoci. Of a total of 257 children, 29.5% had ASO titres of over 166 Todd units. The greatest number of children showed ASO values between 100 and 166 units. The percentage of children showing values over 166 units increased with age until a maximum of 54% was reached between 9 and 10 years. Group A haemolytic streptococci were isolated from five throat swabs, but there were no isolations from ulcers. The values obtained from this survey have been compared with those from a few other developing countries.