Stanford University suspects that the highly contagious norovirus is to blame for the severe gastrointestinal illness that has sickened 52 students in campus dormitories.
The virus, which causes vomiting, diarrhea and dehydration, can quickly sweep through shared housing, hospitals, prisons and cruise ships. About 20 million people a year in the United States get sick from norovirus. Although it leads to 800 deaths and 14,000 hospitalizations a year, the vast majority of people infected promptly recover.
"Because the students all became ill quickly, and in the same vicinity, we believe the pattern is consistent with norovirus," according to Ira Friedman, director of the student health facility Vaden Health Center.
Four students were hospitalized for treatment of dehydration but have been treated and released.
The illness struck quickly within the Florence Moore housing complex, home to 453 undergraduates in seven dormitories, on Tuesday and Wednesday. No new illnesses were reported Thursday.
All students are recovering, although norovirus can spread for more than 72 hours after the initial infection. Sickened students have been warned to wash their hands and limit person-to-person contact even after they feel better.
Santa Clara County health officers will be surveying healthy and ill students within the dormitories to try to identify the source of the outbreak. The investigation is expected to take several days to complete, according to Stanford.
An initial review of food and food handlers in the shared dining hall found that no food or employees were a source of the illness. Just a small dose of the virus -- a few particles -- is enough to cause illness.
Norovirus is a tough virus, surviving for days or even weeks on surfaces at room temperature, and it is difficult to kill. Cold and moisture help it last.
Employees have been scrubbing rooms and sanitizing surfaces in the dining hall, bathrooms and common areas to try to stop its spread.
Unlike bacteria, it is not killed by hand sanitizers; chlorine bleach is the most effective cleanser.
Norovirus is spread through traces of feces on unclean hands or through the air near vomit. A door handle, common serving utensil or food touched by an infected person can serve as a transmission source.
Contact Lisa M. Krieger at 650-492-4098.