The Serological Diagnosis of Typhoid and Paratyphoid Fevers

Abstract

The analysis of the serological results of blood specimens submitted during the course of the past 2 years for the Widal reaction has been made.The sera from cases of typhoid and paratyphoid fever were examined in particular for their agglutinin content for the “H” and “O” antigens of B. typhosus and B. paratyphosus B. The results obtained indicate that it is essential to use the “O” antigen of B. typhosus, but no particular advantage has been derived, from the point of view of early diagnosis, from the use of B. paratyphosus B “O” antigen.A comparison of the value of suitable living and killed antigens has been made. Either type of antigen appears to be equally effective, but for convenience and stability the suspensions issued by the Standards Laboratory, Oxford, have proved entirely satisfactory.Cases showing the serological difficulties which arise when a mixed specific and non-specific form of B. paratyphosus B “H” antigen is used are described.The author is indebted to the Medical Eesearch Council for a personal grant, and to Miss N. A. Davidson for much technical assistance.