Hundreds at schools sickened by virus

Nearly 400 Eastern Massachusetts elementary school and college students, along with their teachers, have fallen ill in the past week with a nasty viral infection that has emptied classrooms and spawned waves of nausea, vomiting, and diarrhea.

At John F. Ryan Elementary School in Tewksbury, an outbreak of gastrointestinal illness started Wednesday and continued through yesterday, when 280 children and 14 teachers were absent, said principal Kevin McArdle . And at Simmons College in Boston, 81 students and staff members have become sick since Dec. 7, with about a half-dozen students so ill they had to be transported from dormitories to hospital emergency rooms, said Dr. Anita Barry , director of communicable disease control for Boston.

At both schools, bathrooms were scrubbed, hand-washing orders were issued, and cafeterias were inspected for signs of contamination. It's too soon to tell whether the measures are making a difference in Tewksbury, but at Simmons, where no new cases were reported yesterday, the efforts appear to have curtailed the outbreak.

Hospital emergency rooms in Boston over the past four days have recorded a significant increase in patients arriving with gastrointestinal illness, prompting the city's health department to issue an alert telling doctors to be vigilant for such ailments and to report suspect ed cases.

So far, everyone infected has recovered within one to two days after drinking plenty of fluids, authorities said. Although the source of the recent outbreaks has not been confirmed, specialists said the culprit is probably the norovirus, a particularly aggressive germ transmitted person to person or harbored in food that has been contaminated by someone who has the virus.

The short duration of the patients' suffering is a major clue that the outbreak is due to norovirus, which can cause more serious complications in the very young and very old.

Preliminary investigations suggest that the current outbreaks are not associated with tainted food and not connected to one another or to a cluster of gastrointestinal illness two weeks ago at a Needham hospital.

Because individual bouts of gastrointestinal illness often go unreported to health agencies, disease trackers said it is impossible to know whether such episodes are increasing. But, they said, a constellation of factors suggests they are.

For one thing, more people dine out -- and dine out more frequently -- than they did 20 years ago, increasing the risk they will consume food tainted with norovirus.

"If you eat out all the time, you're exposing yourself not only to different kinds of food, but also different food handlers," said Dr. Marc-Alain Widdowson , a medical epidemiologist at the US Centers for Disease Control and Prevention .

Additionally, more people live in nursing homes and more people take vacations on cruise ships, where many people can be infected in a short period of time.

"In close settings like a school or a nursing home or a family, the failure to adequately follow good hygiene will manifest itself with spread of this type of disease," said Dr. Bela Matyas of the Massachusetts Department of Public Health .

At Simmons, the outbreak traveled swiftly, although it was not concentrated in any single location, said Dr. Kay Petersen , medical director of the college's health center. To stem the spread, e-mails were sent to students and staff urging them to wash their hands and to stay home if they developed symptoms.

Hand washing is critical with norovirus: The germ is carried in stool, and it takes only a small amount of the virus to spark a cluster of illness.

The college also sanitized dining halls and bathrooms in an attempt to eliminate any trace of the virus.

"We at one point designated one bathroom in the health service for people who were sick and the other bathroom for people who weren't sick, to minimize any exposure," said Petersen, who added that in her nearly two decades at Simmons she has never witnessed so many students stricken at one time with a stomach bug.

In Tewskbury, about 25 fifth- and sixth-graders at Ryan Elementary were sent home Wednesday.

"We said, 'Jeepers, this is really starting up,' " McArdle said. By Thursday morning, the phone in the principal's office was ringing incessantly with reports of children too ill to come to school. "We knew then the tsunami was about to hit," the principal said.

By yesterday, more than one-third of the student body at Ryan was absent, and 14 of the approximately 60 teachers and aides had also called in sick.

As a result, the remaining instructors and students concentrated on review lessons instead of new material.

And the school district decided to delay the release of report cards at Ryan, said Tewksbury Superintendent Christine McGrath .

Stephen Smith can be reached at stsmith@globe.com.