Shigellosis spreads very easily within households and childcare facilities, particularly when there are diaper-age children. Some persons shed this organism even when they are not ill. The only way to prevent infection is to always wash hands well with warm water and soap after using the toilet, after changing diapers, and before preparing food. By law, persons who develop shigellosis may not attend childcare or work as food handlers until stool exams indicate that their infections have ended. From 1993 through 1997, an average of 171 cases of shigellosis were reported annually in Oregon.
Many cases go undiagnosed and unreported.