A second shellfish harvesting area off Vancouver Island has been shutdown by Fisheries and Oceans Canada.

The department has ordered a closure of the Subtle Islands, east of Campbell River, after oysters from the region tested positive for norovirus.

Part of Clayoquot Sound on the west coast of the Island was also closed to shellfish harvesting earlier this month after raw oysters sickened more than 100 people in Tofino.

The Vancouver Island Health Authority says it is currently investigating more than 20 other reports of possible norovirus illnesses linked to raw shellfish and reminds everyone to fully cook oysters before eating them.