Shigellosis is very infectious and spreads easily. Shigella are present in the diarrheal stools of infected persons while they are sick and for up to a week or two afterwards. In that time, they may infect healthy people.
Most shigella infections are the result of the bacteria passing from stools or soiled fingers of one person to the mouth of another person, when sanitation and hygiene are poor. For example, the transmission may happen after:
- being exposed directly to infected stool or indirectly with objects contaminated with stool; for example: in day care centres, if hands are not washed each time you touch children and change diapers
- putting objects that have tiny bits of stool on them - like food, pens, cigarettes etc. - into your mouth
- having oral-anal (mouth to anus) sexual contact
- being exposed to contaminated water or food:
1) if food is contaminated by infected food handlers, or by flies picking up contamination from latrines
2) if drinking water is contaminated by the feces of infected animals or people (e.g. water improperly treated in developing countries)
3) if swimming at beaches with contaminated water