Every year, a large number of people worldwide suffer from gastrointestinal diseases such as diarrhea. Among this population, children under five are particularly vulnerable and are at increased risk of death or malnutrition. Enterotoxigenic Escherichia coli (ETEC) is a major cause of this severe diarrhea. The bacteria first adhere to intestinal cells using colonization factors (CFs), then produce heat-stable (ST) and heat-labile (LT) toxins, which together are responsible for causing the severe diarrheal illness.