Reports of the outbreak at Miami University started last Tuesday when five students came into a school health center at the Oxford, Ohio, main campus, located about 35 miles (56 km) north of Cincinnati, complaining of stomach pain, nausea, diarrhea and vomiting, a university spokeswoman said.
Since the initial reports, a number of students have tested positive for norovirus, said the spokeswoman, Carole Johnson.
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Recent norovirus outbreaks, more on norovirus
200 Ohio university students sick with norovirus symptoms
This transmission electron micrograph, TEM, revealed some of the ultra structural morphology displayed by norovirus virions, or virus particles. Noroviruses belong to the genus Norovirus, and the family Caliciviridae. They are a group of related, single-s
This Sunday, Dec. 27, 2015, photo, shows a Chipotle restaurant at Union Station in Washington. Chipotle said Wednesday, Jan. 6, 2016, it has been served with a federal grand jury subpoena as part of a criminal investigation tied to a norovirus outbreak this summer at one of its restaurants in California. (AP Photo/Gene J. Puskar)
People walk past the entrance to the Russell Investments Center building Monday, Dec. 7, 2015, in Seattle. Over 100 people have gotten sick in a norovirus outbreak at the office building, health officials reported Monday. (AP Photo/Ted S. Warren)
Members of the Red Cross deliberate in protective clothing on board of the ship 'Lady Anne' at the Rhine river in Boppard, Germany, on Tuesday, Nov. 25, 2008. German authorities say 16 people from a British ship on a Rhine River cruise have been hospitalized after an on-board outbreak of norovirus. The ship has been docked in quarantine at the town of Boppard so that they and others can be treated. (AP Photo/str)
Amanda T. Harrington, PhD, assistant professor of clinical pathology at UIC, tests specimens on Tuesday Jan. 12, 2016 using the Verigene System, made by Nanosphere based in Chicago, which helps medical professionals identify gastrointestinal infections like norovirus on the molecular level. UIC is one of the universities/hospitals that has the system. (Phil Velasquez/Chicago Tribune/TNS via Getty Images)
The Norovirus has increased tenfold in Colorado in the last 6 years, with most of the outbreaks showing up in nursing homes. Raquel Rivera cleans the private rooms and the common areas at Chateau des Mons Care and Assisted Living in Englewood, and has a rigorous cleaning regime. Since the home had an outbreak of the virus just over a week ago, along with her everyday routine of soap and disinfectant, Rivera wipes everything down with a bleach solution. She will use the bleach for at least two weeks after the conclusion of the last outbreak. Kathryn Scott Osler, The Denver Post (Photo By Kathryn Scott Osler/The Denver Post via Getty Images)
WASHINGTON, DC - June 10: Rep. Diana DeGette, D-Colo., and Rep. Gene Green, D-Texas, during the House Energy and Commerce Subcommittee on Health markup of a bill to amend the Federal Food, Drug and Cosmetic Act with the goal of improving the safety of food in the global market. (Photo by Scott J. Ferrell/Congressional Quarterly/Getty Images)
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"We have been very diligent in our cleaning and are using products that combat the virus in our residential and dining halls," she said. A small number of the students have gone to a local hospital since the outbreak for dehydration symptoms, she said.
Norovirus is the most common cause of food-borne disease outbreaks in the United States. Infections usually occur in places such as hospitals, cruise ships and universities, where people eat and live in close quarters.
The university, which has a population of nearly 20,000 students, faculty and staff, has not been able to identify the initial source of the virus. Communications from the university recommend students wash their hands with soap and water as antiseptic gels and wipes are ineffective in killing the virus.
During the last several months, outbreaks of norovirus have been reported at restaurants in Kansas and Chipotle Mexican Grill Inc restaurants across the United States.
The Michigan Department of Health and Human Services reported a norovirus outbreak affecting more than 100 students at the University of Michigan last week.
Norovirus affects about 19 million to 21 million people in the United States each year, causing between 570 to 800 related deaths, according to the U.S. Centers for Disease Control and Prevention.