Diarrheal disease is especially problematic since pathogens other than rotavirus cause diarrhea in children living in developing countries. Examples of pathogens causing diarrhea include Vibrio cholera, Salmonella enterica serovar Typhi, Escherichia coli [E. coli], Cryptosporidium, Entamoeba histolytica, and Shigella. Parasitic worms of the Schistosoma genus also cause diarrheal disease in poor countries. In developing countries, infants 0 to 11 months of age are at the highest risk of dying from diarrhea caused by typical E. coli and E. coli producing heat-stable toxin. Children 12 to 23 months of age are at the highest risk of dying from diarrhea caused by Cryptosporidium. It has been recommended that five pathogens (i.e., typical E. coli, E. coli producing heat-stable toxin, Cryptosporidium, Shigella, rotavirus) be targeted in order to decrease the burden of moderate-to-severe childhood diarrhea in developing countries.