DANBURY — An outbreak that caused Western Connecticut State University to close Monday is believed to be norovirus, officials confirmed Monday morning.

Late last week school revealed at least 100 students had been stricken with some kind of illness, prompting officials to close campus late Sunday night as a precaution.

Fourteen students were admitted to Danbury Hospital over the weekend and five tested positive for norovirus, university spokesman Paul Steinmetz said.

WCSU is working with the state and local health departments to test for the virus and attempt to identify how it landed on campus, he added.

The school will announce later this afternoon whether it will remain closed Tuesday.

Officials first became worried after several student athletes became sick on Friday and the school announced Friday evening that as many as 100 students had reported similar symptoms.

Despite some indications the spread had slowed over the weekend, it’s almost impossible to know how many students were already sick or could be developing symptoms now, Steinmetz said.

“There were certainly people who got symptoms over the weekend, but we know about 100 who reported them,” he said. “That’s the number we can get our hands on. With a lot of commuters on campus, we don’t know the exact number. We don’t think it’s an overhwlemingly large number, but that doesn’t help the individual who feels crummy for two days.”

The school does not have an on-campus health center available over the weekend, instead referring resident students to their own doctors, urgent care or the hospital, Steinmetz said.

Norovirus is a highly contagious infection that can cause vommitting and diarrhea and can be picked up through close contact with someone already infected or contaminated food preparation. Symptoms typically begin 12 to 48 hours after exposure, according to the Mayo Clinic.

Norovirus made headlines earlier this year when dozens of cruise ship passengers caught it while at sea and at the Winter Olympics in PyeongChang, South Korea.

Symptoms of the virus can last one to three days and most will recover without any treatment, according to the Mayo Clinic.

zach.murdock@hearstmediact.com