MACAO -- The Health Bureau of Macao Monday said that it has confirmed a collective outbreak of norovirus infection, which involved six travelers from Singapore.

According to the Bureau, the patients included one male and five female, aged between four and 41, and they were members of a travel group of 40 from Singapore.

The six patients developed symptoms of bellyache, diarrhea, fever, etc. on Sunday and were later admitted into local hospitals. Lab test results of their excrement samples confirmed that they were infected with the norovirus.

The Bureau said that its investigation has indicated that the six patients had been to neighboring Zhuhai and ate raw oysters, which are the most common food that can cause norovirus infection, and other seafood when dining at a restaurant there.

Norovirus affects people of all ages, and the viruses are transmitted by faecally contaminated food or water, by person-to-person contact, and via aerosolization of the virus and subsequent contamination of surfaces.