Island Health says at least 30 people have fallen ill after attending an oyster festival held in Tofino last week.

The health authority says it’s talked to 14 people who developed gastrointestinal symptoms after eating cooked or raw oysters at the Clayoquot Oyster Festival, but is aware of 30 people who became ill – including one person who tested positive for norovirus.

Not all of the oysters were consumed at the same event, but all 30 people who got sick ate oysters, Island Health said.

Island Health will be testing leftover oysters from the festival to determine what caused the outbreak of illness.

It’s asking anyone who ate oysters in Tofino last weekend and now has symptoms of gastrointestinal illness to call a communicable disease line at 250-519-3401.

The festival posted a statement on its website stating that any questions about the reported illness should be directed toward Island Health.

The four-day event features costume parties, oyster farm tours, restaurant events and a gala, according to its website.