Local disease control authorities have ruled out the possibility of food poisoning in a recent incident at University of Shanghai for Science and Technology, where more than 40 students fell sick with symptoms of vomiting and diarrhea.

The disease control and prevention center in Yangpu District, where the university is located, confirmed yesterday that Norovirus was to blame for sickening the students. Food and dishware samples tested by the center came back negative for signs of food contamination.

Investigations further found that a student had vomited in a canteen, an incident which is believed to be the source of the outbreak.

Norovirus is highly contagious and can be spread via water, food and air. It can cause gastroenteritis and symptoms of infection include fever, vomiting and diarrhea. People infected usually recover within a few days.

Vomit should be covered and polluted areas disinfected immediately to prevent the spread of Norovirus, experts say.

The university said earlier that it had disinfected all canteens, classrooms, dormitories and other public spaces, and also banned takeaway food from being delivered to its campus.

The campus clinic has cooperated with local hospitals to help sick students receive prompt medical treatment. Most of the sick students have been discharged.