Currently, >90% of cases reported to the World Health Organization (WHO) are from Africa; however, most cases go unreported or do not have a specific bacterial etiology identified.
- It is estimated that there are >3 million cases annually, with >100,000 deaths.
- Spread takes place by fecal contamination of water and food sources. Infection requires ingestion of a relatively large inoculum (compared with that required for other pathogens) of >105 organisms.