Cholera and cholera-like diarrhoeal diseases: why the differences in severity?

Although Vibrio Cholera and several other enterotoxigenic bacteria such as the enterotoxigenic Escherichia coli produce secretory diarrhoea by exactly the same mechanism, cholera is much more severe. It is proposed that this difference in severity may be because while the alkaline diarrhoeal fluid produced in these conditions is optimal for the growth of Vibrio cholera, E. coli and other enterotoxigenic bacteria are inhibited.