Image copyright @Millichap
Several New York City restaurants have closed their doors after diners fell ill and many others reported vomiting and diarrhea.
The Health Department said there were 60 cases of the stomach bug in the borough of Queens on 12 January.
Rarest, a restaurant known for its oysters, has now shut down.
The government crackdown comes as the stomach bug remained at a high peak in two states.
So what exactly is the bug?
What is the bug?
While no-one seems to know for sure what causes norovirus, there are different theories.
One of the key theories is that it is a virus that replicates better in warm, moist environments.
“There is some evidence that because the amount of virus in human vomit is relatively small, it may be able to survive the digestion process,” Dr Julia Sexton, a gastroenterologist at NYU Langone Medical Center, told CNN.
Image copyright PA Image caption Roughly 1.5 million cases of the bug are reported globally every year
Viruses tend to make people nauseous – but unfortunately the stomach bug does not lead to actually pass a person’s blood stream.
“When it does get into the bloodstream, it travels incredibly rapidly,” said Dr Sexton.
“When a virus enters the blood stream, it will stay there and spread wherever it spreads, both in humans and in rodents.”
How bad is it?
Norovirus is known to spread as the bug usually has a sufferer for up to a week and if left untreated, can lead to dehydration.
Around 1.5 million cases of the bug are reported every year in the US, but the current outbreak is much higher than usual.
Image copyright @mmboston Image caption NHS posts a checklist of what to look out for when you get a norovirus
Which restaurants have closed?
Several eateries in the New York City borough of Queens have shut down due to the illness.
Rarest, a restaurant that stocks oysters and scallops, was closed last week after 60 people reported symptoms, including vomiting and diarrhoea.
#nomorotize in local restaurants? Follow our tips so you won’t end up in this situation: https://t.co/p2cZxOtPqX — New York City Dept. of Health (@NYCHealthDept) January 28, 2019
Two other restaurants – Lulu’s on Broadway and Manoli’s Bar – also closed due to the outbreak.
And the seaside town of Montauk on Long Island had banned eating raw oysters because of the outbreak.
However, the mayor of Montauk, Gary Bagneris, has since lifted the ban on raw oysters.
How have restaurants managed to stay open?
Many owners who have reported to Health Department inspectors that they were affected by the norovirus say the restaurateurs have taken extra precautions to avoid it.
“After we received a call from one of our staff members, we immediately sanitised our kitchen and all kitchen equipment,” said Michael Denckas, owner of The Loft at Francis Square at Park Avenue South, which closed after five employees fell ill.
Image copyright @lodge5110 Image caption Mr Denckas said his staff are taking extra precautions to avoid catching the bug
Danger zones for norovirus include potable water, swimming pools, unhygienic food preparation areas, and food preparation areas where people gather together for parties.
“We had diarrhoea, vomiting and fever. We’re all very healthy and cheerful now,” said John Zumbrun, a restaurant manager from Astoria, who said his staff are now taking extra precautions.
He said at his restaurant, some customers have been dropping off their food, and a second in his line of work has been vomiting.
Mr Zumbrun said the new strategy could be harmful.
“On opening day I had all the employees wash their hands a lot more,” he told CNN.
“I don’t think it’s been successful so far, but we’ll have to see.”