The Centre for Health Protection is investigating an acute gastroenteritis outbreak involving 22 people who travelled to Gansu July 21 to 28.

The group, comprising seven men and 15 women aged 15 to 46, have come down with diarrhoea, vomiting and fever since July 22. Nineteen saw doctors on the Mainland and six sought further treatment in Hong Kong.

They are all stable and no hospitalisation was required.