MADISON, Wis. -- The University of Wisconsin-Madison said it is continuing to monitor reported cases of gastroenteritis among students following the cases of suspected norovirus that were seen at University Health Services on Nov. 7.

On Friday, the university sent out an e-mail advising students to use extra hand-washing precautions and advising how best to care for themselves if they fell ill.

Additional information about how to clean residences where people have been sick was also posted to the UHS Web site.

Since Nov. 7, University Housing has reported 63 students in Sellery Hall dormitory with illness characterized by vomiting and diarrhea. Sellery Hall houses 1,100 residents.

University Housing staff are continuing to implement stringent cleaning procedures to control the spread of illness.

On Nov. 13, UHS said it received reports of several dozen sick students in some of the sorority and fraternity houses and a few suspected cases among students living in off-campus housing.

Friday's e-mail asked residence managers in fraternities and sororities and off-campus housing to alert UHS if they encountered residents with symptoms of gastroenteritis. A second e-mail went out to UW-Madison faculty and staff.

Norovirus is easily transmitted from person to person via contaminated hands, surfaces or foods. It is characterized by acute gastrointestinal illness with vomiting and diarrhea. Symptoms are usually very sudden in onset, might be severe and typically resolve within 24 to 48 hours.

Health officials said people who are sick should drink small amounts of clear fluids throughout the day to prevent dehydration.

Students who are sick are being encouraged to stay home from class and work and avoid large gatherings.