Epidemiologic study of diphtheria in El-Minia governorate [Upper Egypt]

ABSTRACT

During the period 1981 through 1985, a total of 1605 cases of diphtheria was reported in El-Minia governorate with a toll of 530 deaths. Hence, the occurance of a diphtheria epidemic was very likely. The objective of this study was to evaluate the present epidemiological situation at this locality. Both retrospective and cross sectional methods were utilized to achieve this objective. Results of retrospective study revealed that the incidence rate ranged between 6.6 and 26.9 cases/100 000 population with mortality rates ranging from 2 to 6.6 cases /100 000 population. The case fatality ratio [C.F.R.] ranged between 24.1% and 46.7% in the whole governorate, whereas it was 33.3% in rural population. On the other hand, the cross sectional study revealed an incidence rate of 51.9 cases /100 000 rural population compared to 3.5 cases /100 000 urban population. The difference was statistically highly significant [P 0.001]. Epidemiological evidence suggested that the continued presence of susceptibles and unidentified carriers with the possible introduction of toxigenic strains of Corynebacterium diphtheriae [C.diphtheriae] but international travellers would facilitate the spread of disease either through direct transmission of these strains or indirectly via lysogenic conversion of non-toxigenic strains into toxigenic ones. Recommendations emphasized the continuation of obligatory primary DPT vaccination and the routine use of TD boosters for older children and adults especially in rural communities