Shigella is a genus of enteric bacteria that in humans cause dysentery; its major symptoms are fever and diarrhea, which are due to invasion. Several genetic determinants, located both at virulence plasmid and nucleoid, are responsible of pathogenesis. Outbreaks occur worldwide, as shigellae spread person-to-person and contaminate, due to inappropriate human activity, water and food, such as milk. No vaccine is yet available for this pathogen. Consequently, to avoid about 1 million people death per year, it is crucial to improve nutrition, hygiene, education, food safety, and detection of shigellae, especially in less-favored world areas where this pathogen is still prevalent.