The epidemic that sickened more than 100 University of Wisconsin students has been identified as the highly contagious norovirus, officials said Friday.

Through an online survey, University Health Services epidemiologist Craig Roberts has determined 137 people have contracted the virus in the past several weeks, 90 of whom live in Sellery Hall, 29 of whom live in other southeast residence halls and 11 of whom live at various locations on Langdon Street.

Roberts said the virus appears to have been contained, as all cases that have been reported in recent days do not appear to be part of the outbreak.

However, Roberts added it could easily begin spreading again.

“It looks like the outbreak is over, but of course, it could be reintroduced into another dormitory or fraternity or apartment or house or anywhere people are sharing common living space in some way,” Roberts said.

Affected Langdon Street communities included Delta Tau Delta fraternity, the Evans Scholars house and the Delta Gamma sorority, where President Christine Binkley estimated that 60 members were sick at some point.

In an e-mail to The Badger Herald, UHS spokesperson Mary Makarushka said she credited UW staff and students’ efforts for helping stop outbreak.

“The UW Housing housekeeping staff did an amazing job — disinfecting everything from bathrooms to elevator buttons,” Makarushka said. “And the students themselves did an amazing job of taking precautions to protect themselves and others, and staying calm. Those two things together really helped contain the disease as quickly as possible.”

Norovirus is commonly mistaken for the stomach flu. Symptoms include nausea, vomiting, diarrhea and headaches. These symptoms last for 24 to 48 hours.

Roberts described it as the “common cold of gastroenteritis,” and said there are always cases of it present throughout any community. Roberts said there are an estimated 23 million cases of the illness in the United States each year.

As a result, norovirus is only investigated when there is an outbreak of cases in a concentrated area.

“We look at anybody who had vomiting or diarrhea in that period, even if it is not norovirus,” Roberts said.