Shigella is a family of bacteria that can cause diarrhea in humans. Shigella were discovered over 100 years ago by a Japanese scientist named Shiga, for whom they are named. There are several different kinds of Shigella bacteria: Shigella sonnei, also known as “group D” Shigella, accounts for over two-thirds of shigellosis in the United States. Shigella flexneri, or “group B” Shigella, accounts for almost all the rest. Other types of Shigella are rare in this country, though they continue to be major causes of disease in the developing world. One type found in the developing world, Shigella dysenteriae type 1, can be responsible for deadly epidemics.
