Regarding ETEC, true is

Enterotoxigenic E.coli: Diarrhea caused by ETEC is of two epidemiological types Diarrhea caused by ETEC is endemic in developing countries in the tropics. Common in all age groups. Traveler's diarrhea: Adheres to the intestinal mucosa which is mediated by colonization factor antigens. Produces enterotoxin which may be heat liable or heat stable. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 285