Prevalence of diphtheria carriers in a population with disappearing clinical diphtheria.

Ten years ago the incidence of diphtheria was relatively high in Greece and a survey of school children had revealed a carrier prevalence of non-toxigenic Corynebacterium diphtheriae of 3,4%. A similar survey undertaken now has revealed that the disease seems to be disappearing. Among 895 school children (6-13 years-old) in seven primary schools of different socioeconomic levels, only seven were carriers of non-toxigenic C. diphtheriae strains, corresponding to a prevalence of 0.8%. Toxigenic strains were not found. All carriers were pupils of the same school, and the carrier state was more frequent during the first three school years. All the carriers were found in a school serving a socioeconomically deprived area. A statistically significant association was found between the prevalence of C. diphtheriae and of other non-pathogenic Corynebacteria.