MADISON, Wis. -- The number of suspected norovirus cases at the University of Wisconsin-Madison is growing.

UW-Madison officials said Friday that 63 students in Sellery Hall dormitory have become sick since Nov. 7 with illness characterized by vomiting and diarrhea. Sellery Hall houses 1,100 residents.

University Health Services has also received reports of several dozen sick students in some sorority and fraternity houses and a few suspected cases in off-campus housing.

UHS epidemiologist Craig Roberts said norovirus is suspected but lab tests will say for sure.

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.

Students were told how to clean homes where people have been sick and to use extra hand-washing precautions. Additional information was also posted to the UHS Web site.

Health officials said symptoms of vomiting and diarrhea come on quickly and last from 24 to 48 hours.

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