More than 150 of the 1,000 attending the conference became ill with nausea and diarrhea symptoms. Most of those who got sick were teenagers.
"Woke up everybody saying their stomachs were hurting, diarrhea," high school student and attendee Kenneth Moore Jr. said.
He didn't get sick, but a number of his friends did.
"I know I got a stomach problem," Deshawn Harris said. "I'm going see what's wrong with me and see what's going on."
Ambulances began arriving at the Sheraton Hotel in downtown Raleigh just after 10 a.m. Saturday and five patients were taken to the hospital. The rest of the ill were isolated in their rooms.
Wake officials said lab results confirmed the norovirus diagnosis. Norovirus is a stomach bug with symptoms that typically last about two days.
Epidemiologists say it's very infectious and very resilient.
Investigators are looking for the source of the virus and have been working with the hotel and the Raleigh Convention Center staff where many conference attendees ate a meal the night before becoming ill.
“Norovirus investigations are complex,” said Wake County Environmental Health and Safety director Andre Pierce. “We have to interview everyone involved, look at lab samples and work closely with food handlers and preparers. In some cases, we never definitively find the source of the norovirus.”
Experts say the point-source of a norovirus outbreak can be very hard to pin down.
Since the outbreak, health officials have temporarily changed food-handling procedures in the Convention Center and at three other restaurants where some of those who got sick had eaten.
For the time being, no more bare hands when handling food.
They've also required chlorine scrub downs at each of those places - chlorine is known to be effective in fighting against norovirus.
And while county health officials say they can't pinpoint the cause of the sickness, but they say they can assure people that the widespread risk is gone.
Health officials said control measures have been put in place to reduce the spread of norovirus, including extra disinfectant and sanitation efforts in food preparation areas.