A Challenge to the Validity of the Vi Test for the Detection of Chronic Typhoid Carriers

Abstract

A systematic bacteriological and serological examination of 1358 male Bantu in the Johannesburg area revealed that: 199 (14.6%) were Vi reactors; at least 94%, and proably 98.5% of the reactors were of the false positive type; a statistically significant relationship existed not only between the presence of Vi agglutinins and the recovery rate of Salmonella typhi, but also between the Vi agglutinins and the recovery rate of Shigella organisms; a number of cases, in which S. typhi was recovered from urine only, appeared to be subclinical. of short duration and usually not associated with antibody formation. These cases may play a significant role in the epidemiology of typhoid fever.