A study of the serological types of haemolytic streptococci in relation to the epidemiology of scarlatina and other infections due to these organisms

Abstract

1. The paper records the result of a study of the serological types of haemolytic streptococci in scarlatina, puerperal fever, erysipelas, ear infections, tonsillitis, erythemas, etc., and normal throats, and their epidemiological relationships.2. Tables and charts are given showing statistical records of scarlatinal cases which occurred over a period of 16 months in Edinburgh, a city with a population of about half a million inhabitants. In all there were 2287 cases. Of these 2169 were treated in an infectious diseases hospital, and were thus readily accessible for investigation. 1364 of the cases were school children. The strains of haemolytic streptococci from 1664 of the hospital-treated cases were serologically examined.3. During an epidemic of scarlatina certain schools practically escaped, but in these there was a proportionately greater number of cases the following year, as compared with those schools which had suffered heavily the previous season.4. Depending on the types of haemolytic fltreptococci isolated, scarlatina patients have been divided into three main categories: (1) pupils or school children, (2) “pupil-contacts” (families of pupils), and (3) “non-pupil-contacts” (famines without children of school age). The types of haemolytic streptococci found in these three groups have been correlated. There was a similarity in the types found in pupils and “pupil-contacts”, but not in those of pupils and “non-pupil-contacts”. Those types obtained from “pupil-contacts” and “non-pupil-contacts” were related. These features have been discussed.5. Certain types of haemolytic streptococci predominated in the pupil cases. These were for the most part the epidemic types. The non-epidemic types, sporadic in appearance, were found mostly in “non-pupil-contacts”. “Pupil-contacts” occupied an intermediate position.6. One main epidemic type ran through the three classes of patients. It was later replaced by another type.7. The majority of cases of scarlatina which occurred in a school at a particular time were due to one type. It tended to persist despite the sporadic occurrence of other types. On occasions two types were present concurrently, but usually the one disappeared, and afterwards the other produced most of the cases.8. The types of haemolytic streptococci in scarlatina, erysipelas, otitis media and mastoiditis, tonsillitis, and other streptococcal infections have been compared and the findings discussed. For the most part there was a correlation of types among all these conditions, and these types appeared to be responsible for a single epidemic of streptococcal infections.9. The major epidemic types found simultaneously in the City of Edinburgh and in a small community, 12 miles distant, differed.10. The types of haemolytic streptococci isolated from the throats of nurses in a general hospital bore little relationship to those isolated from medical officers and nurses in an infectious diseases hospital. The common epidemic types were present in the latter.11. Correlations were shown to exist between the types of haemolytic streptococci in scarlatina patients, and those isolated from various members of their families, in 50% of the occasions in which the organisms were found.12. The rapid change in the types occurring in the nasopharynx and the problem of immunity have been investigated and discussed in the case of a person exposed to massive infections with haemolytic streptococci.13. Haemolytic streptococci on the handkerchiefs of scarlatina patients were viable after 4 weeks in most cases and after 7 weeks in two cases. After 15 weeks they were all dead.14. Haemolytic streptococci were isolated from toys and fruit taken from scarlatina patients.