A Vi variant of Salmonella typhi and its application to the serology of typhoid fever

Abstract

1. The description of a strain which behaves as a pure Vi variant of S. typhi is given. Complete absence of H antigen from it is demonstrated. The non-interference in its Vi agglutinating activity by the very small amount of O antigen contained in it is shown. This strain has been designated “Vi 1”.2. With the help of this strain, the practical applicability of Vi agglutination as a reliable method for the routine serological diagnosis of typhoid infection and for the detection of typhoid carrier condition, in preference to O and H types of agglutination, is stressed.