1. The bacteriological examination of the throat or nose in 100 cases of scarlet fever on admission to hospital showed the following incidence of the different serological types of streptococci. Of 91 cases yielding positive results on the first examination, haemolytic streptococci of Type 1 were found in 8, Type 2 in 14, Type 3 in 26 and Type 4 in 12; the remaining 31 fell into the heterogeneous group. In the 9 patients who gave a negative swab on admission a later test showed Type 1 in 2 cases, Type 2 in 4 cases, Type 3 in 1 case and heterogeneous strains in 2 cases.2. The heterogeneous group comprised individualistic strains, none of which occurred with sufficient frequency to form a fifth type.3. In 50 out of the 100 cases examined at weekly intervals the type of streptococcus remained the same throughout the attack.4. In 50 cases there was a change of type during the course of the disease; a second type appeared in 38, a third in 10 and a fourth in 2.5. The change of type was considered to be a reinfection since it appeared most often in the youngest children and after the 3rd week of treatment; the source of reinfection was traced in two instances.6. In 3 patients, in whom the Dick reaction remained positive, the appearance of the new type coincided with a second attack of clinical scarlatina.7. Of the 50 patients in whom no change of type was demonstrated 20 still carried the haemolytic streptococci on discharge after periods in hospital ranging from 4 to 8 weeks.8. Of the total 100 cases there were on discharge 49 throat carriers of haemolytic streptococci and 6 nose carriers. None of the 55, so far as was ascertained, gave rise to “return cases” of scarlet fever.9. There was evidence of correlation between serological type of streptococcus on the one hand and severity of scarlatinal attack and occurrence of complications on the other. The importance of this in hospital practice is emphasised.10. The Dick test and Schultz-Charlton reaction were carried out on all cases in the series; the results indicated that the four serological types have different immunological values.11. The evidence in favour of qualitative as opposed to quantitative differences in toxin production by the different types is discussed.
Bacteriological and Clinical Study of One Hundred Cases of Scarlet Fever