Norovirus outbreak in Canada heres whats triggering the vomiting bug Gastrointestinal illness cases have been linked to raw oysters from B.C. BC주 양식장의 생굴과 관련된 위장병 사례가 발생하여 해당 시설이 폐쇄되었습니다. But the health agency explained that its not clear what, exactly, caused the problem.