Around 200 people who were present at a catered party at an office building in downtown Seattle have fallen ill after being infected with norovirus.

Medical epidemiologist Dr. Megan Kay, a representative of the public health department, informed that every food-service location inside downtown Seattle’s Russell Investments Center has been closed by the public health officials; these also include a Starbucks location.

For those who don’t know: CDC guidelines suggest that spreading of norovirus is possible through an infected individual, contaminated surfaces, and contaminated water and food.

According to latest reports, around 200 out of the almost 600 individuals present at the party last Tuesday have fallen ill. Kay feels that that the number will go up as the health officials will move forward with their investigation into the actual cause of this norovirus outbreak. The party was catered by Bon Appetit Management Co., a California-based company.

The catering company is saying that the source of the illness is still unclear and like anyone else involved in this disaster, they are also extremely eager to know exactly when and how it began. The company further said that they along with their food safety experts have taken necessary steps for disinfecting the surfaces in their facility and have also done the needful for ensuring food safety.

Among the patients, two had to be hospitalized overnight and another eight needed to visit an emergency room due to their illness. Kay said that right now there’s no information available on the exact conditions of these patients.

During the weekend, the building got disinfected partially for addressing vomiting in the restrooms and for cleaning certain surfaces including door knobs.

Norovirus results in inflammation of the infected person’s intestines or stomach or both along with acute gastroenteritis. The condition is marked by symptoms such as diarrhea, nausea, and stomach pain.

Must Read: Norovirus outbreak in Seattle sickens nearly 200

According to statistics put forward by the centers for Disease Control and Prevention, it’s the most common cause of acute gastroenteritis and food-borne disease outbreaks in the US. Norovirus results in around 19 to 21 million illnesses every year, which include 570 to 800 annual deaths.

A man called Bryan has reported on a blog of the health department that both he and his eight month pregnant wife have fallen ill with norovirus. He further informed that to get rid of the symptoms he had to visit the emergency room and receive intravenous fluids.