The Oregon State Public Health Laboratory says recent fecal samples from some of the nearly 100 people who reported getting ill after visiting Elk Lake Resort in recent weeks have tested positive for Norovirus, officials said Thursday.

Although the drinking water at Elk Lake Resort tested positive for Coliform bacteria, it is now conclusive that E. Coli was not the cause of reported illnesses, according to Deschutes County health officials.

The source of the Norovirus is still unknown, they said, and no new reports of illness occurring after Thursday, July 14 have been reported. The total from before that is close to 100, they said.

Norovirus is a virus that causes acute gastroenteritis in humans. The most common symptoms of acute gastroenteritis are diarrhea, vomiting, and stomach pain.

Norovirus is also described as “Norwalk-like viruses.” Norovirus spreads from person to person through contaminated food or water, and by touching contaminated surfaces. Norovirus is recognized as the leading cause of foodborne-disease outbreaks in the United States. Outbreaks can happen to people of all ages and in a variety of settings.