A virus carried on Kaiser rolls caused the outbreak of what seemed to be food poisoning in Douglas Hall last week, NIU officials said Sunday.

“You got it from food, but it was not food poisoning,” said Pat Hewitt, associate vice president of Business and Operations. “It was not caused by improperly prepared food—chicken salad left out too long or egg rolls that weren’t cooked enough.”

NIU and DeKalb County Health officials met late Friday afternoon and determined that a virus made about 150 students sick.

The Norwalk Virus, sometimes called the winter vomiting disease, is an acute, infectious, non-bacterial disease that affects the gastro-intestinal area, Hewitt said.

“It’s very mysterious and hard to track,” she said. Doctors first identified the virus in 1968 after an apparent food poisoning incident at a Norwalk, Ohio, grammar school, Hewitt said.

The virus is found in the small intestines and is fecal-borne, she said. “It’s brought into the food chain by people who don’t wash their hands properly after they use the bathroom,” Hewitt said.

Officials determined that someone who had the virus handled the Kaiser rolls at the Douglas Hall dining room. “They are self-served, and people often touch one or two before they pick one,” she said.

Hewitt said she did not know if a food service employee or someone eating at the cafeteria had the virus and touched the rolls. “It probably wasn’t started in the bakery where the rolls are made because people in other residence halls would have gotten it,” she said.

Precautions are being taken to prevent further spread of the virus. “If food service employees feel sick, we are telling them to stay home,” she said.

State health inspectors checked the Douglas Hall kitchens thoroughly and did not find any problems, Hewitt said. “The inspectors did not find that people were preparing food carelessly,” she said.

Although she said the disease was not spread by “people who were normally unclean,” Hewitt advised students to carefully wash their hands with soap and water after using the bathroom

People get sick from the virus about 48 hours after they come in contact with it, so another wave of students might get sick this week, she said.

Because the virus is spread through water, food and from person-to-person, officials are warning students not to use a friend’s towels and not to touch food they don’t plan to eat or throw away.