An investigation of the normal agglutinins for typhoid and paratyphoid bacilli in human sera in Victoria, and the interpretation of the Widal test

Abstract

1. Five hundred samples of sera sent for the Wassermann test were tested for the presence of H and O agglutinins for Bact. typhosum, Bact. paratyphosum A and Bact. paratyphosum B. Histories were obtained of nearly all those persons whose sera gave H agglutination at dilutions of 1:40 or higher, or O agglutination at 1:80 or higher. It was found that at least 20 people in this series had been inoculated or had suffered from enteric fever. The remaining 480 were considered to be normal. This assumption is likely to be correct in this community where typhoid is the only enteric fever which occurs, and that rarely, and where inoculation is not commonly practised.2. The results are tabulated so as to show all the combinations of agglutinins which occurred at serum dilutions from 1:20 to 1:1280. Out of sixty-three possible combinations of agglutinins twenty-three were found to occur.3. The interpretation of the results for single agglutinins and for certain combinations of agglutinins is discussed, and also the application of these results to the diagnosis of typhoid fever in this community and enteric fever elsewhere.4. A comparison of the local “level” of normal agglutinins with that of other communities is made, and the origin of normal and co-agglutinins discussed.