After 32 people associated with the Pyeongchang Olympics were diagnosed with norovirus on Tuesday, 54 more are known to have caught the highly contagious illness as of late Wednesday, the Korean Centers for Disease Control and Prevention (KCDC) announced.
No athletes are known to have been affected by the virus, which is accompanied by abdominal pain, severe vomiting and diarrhea.
Norovirus is commonly spread through contaminated water or food that has come in contact with the virus during preparation and most frequently occurs in crowded environments like cruise ships or hospitals, according to the Mayo Clinic.
Police officers, security personnel and food preparation staff are among those affected, KCDC Director Kim Hyun-jun told reporters. Security staff were the first reported with the virus.
Around 1,200 security staff have been quarantined, forcing organizers to call in military personnel to replace them.
“In order to stop the further outbreak of the virus we’re quarantining patients beginning from the diagnosis to the treatment,” Kim told reporters. “We’re going to minimize this outbreak.”
Opening ceremonies in PyeongChang are scheduled for Friday, though competition is already underway.
The New York Times reports that the KCDC has yet to discover the source of the virus.
“We are still testing the food and water in all three venues,” KCDC representative Hong Jeong-ik told The Times. “But we still haven’t figured out the source yet. It’s going to take some time.”
The original security personnel diagnosed with the virus were staying at a youth training center near PyeongChang. But the expansion of the outbreak demonstrates that the virus has traveled elsewhere around Olympics activity.
Kim told reporters that anyone diagnosed with the virus should expect to be affected for three days.
“After the diagnosis, you’re removed from your accommodation facility if you have the virus. The quarantine usually ends in 48 or 72 hours.”