It was shown in the passive hemagglutination test (PHAT) with a type-specific somatic antigen on 147 carriers of toxigenic diphtheria bacilli that the PHAT titres of 1/80 and over were determined in 64% of bacteria. In the process of carrier state of toxigenic bacteria antimicrobial antibodies were detected in 79% of the children; after the release from the carrier state, the percentage was from 57 to 26, depending on the time lapse after it. Among the carriers of nontoxigenic diphtheria bacilli the PHAT titre of 1/80 and over was established in up to 20% of children, and only in those which were in the focus of toxigenic bacilli carriers. The applied test could be used for epidemiological purpose to determine the spread of the carrier state of toxigenic bacteria in a collective body.
