In June 1992, 19 cases of typhoid fever were reported from the town of Al- Mudhnab (population 10,000) in the Qassim region of central Saudi Arabia. Ten of the cases were females (53%), and these were clustered by onset in a 15-day period. Cases in boys followed the girls and were more dispersed over time. Cases included 14 school-age children, four pre-school children, and the wife of a girls' school bus driver. The attack rates (AR) did not differ between boys' and girls' schools and ranged from 5.5 to 15.87 per 1,000 in six different schools. All patients except one lived within two blocks in one quarter of the town. Typhoid fever was associated with attending a school potluck dinner (OR=5.31; 95% CI 1.02, 28.85) or eating food prepared for that dinner (OR =6.95; 95%; CI 1.40, 36.61). Cake with cream topping from the dinner was kept overnight at room temperature and served to girls on the bus the next day. The OR of eating leftover cake on the school bus and becoming ill was 11.04 (95% CI 1.59, 95.27). The localization of this outbreak by time and place and by the age groups affected supports the conclusion that the outbreak was foodborne. The most likely food was cream topping on the cake. Lessons on proper food handling and storage should be included in home economics classes.
Conclusion: