Travellers diarrhoea is caused by

Enterotoxigenic E.coli (ETEC): Diarrhea caused by ETEC is of two epidemiological types Endemic in developing countries causing watery diarrhea to fatal disease. Traveller's diarrhea seen in persons from non-endemic areas visiting endemic areas. Ref: Textbook of microbiology; Ananthanarayan and paniker's; 10th Edition; Pg:285