Shigella is a highly contagious bacterium which infects the intestinal tract. In general, S. dysenteriae , S. flexneri , and S. boydii account for most isolates in developing countries. Conversely, S. sonnei is most common and S. dysenteriae is least common in developed countries. Shigella is spread by direct or indirect contact with infected individuals. Food or water may be contaminated by direct or indirect contact with fecal material from infected people.
Shigella often causes outbreaks in daycare centers.
Parents often acquire the illness from their children. Symptoms include diarrhea which may be mild or severe, along with fever and nausea. The diarrhea may be watery or bloody. Vomiting and abdominal cramping may also occur. Some infected people may not show any symptoms.