Most of the 100-plus people infected with norovirus last month had eaten at a local Subway franchise.

The Star Press reports an investigation by the Blackford County Health Department (that’s in Indiana) was unable to determine whether a customer or an employee spread the virus, also known as a stomach bug and food poisoning.

"We don't know how it bounced in there," said Linda Briles, an environmental health specialist at the department. "We may never know. I use the term 'bounced in there,' either www.barfblog.com/blog/152553/12/01/14/eat-fresh-90-sick-norovirus-linked-indiana-subwaywith an employee or a customer, I don't know. But it bounced in and went from there."

She said the virus could have been spread by a customer who failed to properly wash his or her hands after using the restroom. "A customer could have left it on a door knob," Briles said. "It (transmission) is fecal-oral. Or an employee could have caused it by poor hand washing."

An outbreak investigation report from the state department of health won't be completed for several months, spokeswoman Amanda Turney said. A state epidemiologist will conduct a "hot wash" meeting today with the county health department staff to identify lessons learned from the outbreak.

"I want to do a final hot wash before I release my report (of the investigation to the public)," Briles said. "It should be available after I get down to the state health department and have it checked by the media (relations office)."

Briles said tests showed that more than one Subway employee was infected with the norovirus. "They were sick the same time everyone else was," Briles said. To her knowledge, the infected employees were not sick before the outbreak.

There has been an Indiana administrative code regulating food workers with diagnosed illnesses since 2000, but it wasn't being enforced in Indiana until 2008.

Under the code, any food employee who is diagnosed with one of the following illnesses must be excluded from the food establishment: salmonella, shiga toxin-producing E. coli, shigella, hepatitis A or norovirus.

From company headquarters in Milford, Conn., Subway public relations manager Kevin Kane said, "Upon learning of the norovirus investigation by the Blackford County Health Department, the franchisee in Hartford City voluntarily closed the restaurant and had an independent company come in to thoroughly clean and sanitize the restaurant. This was in addition to the stringent cleaning and sanitizing procedures practiced here on a daily basis.

Despite hiring an independent contractor to sanitize the restaurant, Subway was cited by Briles for mold, dirty floors and other violations after re-opening.

Cleaning up vomit promptly is crucial to containing the spread of bugs like norovirus as 300 staff and students at a Jesuit high school in San Francisco discovered Wednesday.

The outbreak at Saint Ignatius College Preparatory school, initially believed to have been caused by a virus, sent a handful of the sickened students to hospital emergency rooms for treatment of dehydration, principal Patrick Ruff said.

School spokesman Paul Totah said roughly 300 pupils in all, out of the school's 1,360-member student body, were believed to have been affected in some way.

Extra maintenance staff were brought in to scour the entire school with a bleach-based solution, and the process will be repeated on Thursday, Ruff said.

The school consulted with San Francisco health inspectors, who visited the school Wednesday and ruled out cafeteria food or waterborne sources for the outbreak, he said. Further testing is needed to determine whether norovirus, a common cause of gastroenteritis, was the culprit.

Dr. Tomas Aragon, San Francisco's chief medical officer, said the outbreak may have originated from a single infected student who got sick in an often-used doorway.

"A student vomited on central doors, on the rods that open these big doors. Then the bell rang and a lot of students went through that door."

Aragon said the norovirus can survive on surfaces for days and is highly contagious.

The Victoria Times Colonist (that’s in British Columbia, in Canada) reports 147 delegates are believed to have contracted norovirus during the final night of a four-day university journalism conference at the Harbour Towers Hotel and Suites, and the final tally has yet to come.

More than one- third of the 370 delegates attending the Canadian University Press national conference went down with severe nausea, vomiting and diarrhea.

Eighteen hotel staff also contracted the virus about 24 hours after the first few students showed symptoms, according to hotel management.

"That's a really significant outbreak," said Dr. Murray Fyfe, chief medical health officer for the Vancouver Island Health Authority. "And the fact that we had people who were perfectly well and then became ill after coming into contact with others or got sick when they got home, that's really typical of norovirus."

The highly contagious virus kept some delegates isolated in their hotel rooms for days before they could check out.

 The most effective public health measures to protect consumers from exposure to norovirus in oysters are to produce oysters in areas which are not contaminated or to prevent contamination of mollusc production areas.

And current methods used to remove norovirus in shellfish are not an effective means of reducing contamination.

So says the European Food Safety Authority (EFSA) Panel on Biological Hazards (BIOHAZ Panel) in a new risk assessment.

The Panel recommends establishing acceptable limits for the presence of virus in oysters that are harvested and placed on the market in the European Union. In addition, an EU-wide baseline survey on norovirus in oysters should be carried out to provide information on overall consumer exposure as well as the public health impact of control measures.

Norovirus is transmitted through the consumption of food or water contaminated with fecal matter or through person-to-person contact or contact with infected surfaces. Oysters contaminated with norovirus pose a particular risk to human health as they are often consumed raw.

EFSA’s BIOHAZ Panel concludes that norovirus is highly infectious and that the amount of the virus detected in oysters linked to human cases can vary greatly.

Scientists highlight that norovirus is frequently detected in oysters in Europe which comply with existing EU control standards for bivalve molluscs.