People get shigellosis by putting anything in their mouth that has touched infected feces, by eating or drinking food or water contaminated with the bacteria, or through contact with someone who is sick or has recently been sick with Shigella infection. It can also be spread sexually by oral-anal contact.

Foods that have been identified in Shigella outbreaks include salads (potato, shrimp, tuna, chicken, turkey, macaroni, fruit, and lettuce), chopped turkey, rice balls, beans, pudding, strawberries, spinach, raw oysters, luncheon meat, and milk. Contamination of these or other foods is through the fecal–oral route.

Among MSM, HIV infection and direct anal contact were independently associated with shigellosis. This is the first population-based study of risk factors for shigellosis that evaluates sexual practices, and HIV status. This strongly supports shigellosis as a sexually transmitted disease (STD).