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What is norovirus? Symptoms to know and how to prevent infection

Norovirus is highly contagious and very hard to kill.
Image: Oasis of the Seas
Royal Caribbean International's Oasis of the Seas.Chris Ison / PA Wire/AP file
/ Source: NBC News

Norovirus is a highly contagious virus commonly known as stomach flu or winter vomiting disease. It spreads most common in the winter when people are also battling influenza.

Norovirus can be spread by eating contaminated food, touching a contaminated surface and then touching your mouth, or by having contact with someone who is infected. It spreads especially fast in places where people share close quarters, like cruise ships, hospitals and schools. The bug is notorious for causing large outbreaks of sickness. It takes only a tiny bit of virus to make someone ill.

The virus causes a person’s stomach or intestines to get inflamed and is the most common cause of acute gastroenteritis — stomach upset — in the U.S., making about 20 million people sick each year, according to the Centers for Disease Control and Prevention. Food poisoning can be caused by norovirus: The bug is the leading cause of illness and outbreaks from contaminated food in the U.S.

What are the symptoms?

The average incubation period for norovirus-associated stomach upset is 12 to 48 hours. The most common symptoms include diarrhea, vomiting, nausea and stomach pain. Patients can feel extremely ill.

What is the treatment?

There’s no real treatment for it except for waiting it out. It’s best to drink plenty of liquids to replace fluid lost from throwing up and diarrhea and prevent dehydration. Most people get better within one to three days.

How can infections be prevented?

Wash your hands: Soap and water can wash norovirus away, but it takes a good scrubbing and really hot water to kill it. Alcohol-based hand sanitizers do not kill norovirus.

Norovirus can persist on surfaces for several days even at room temperature. The CDC recommends using bleach to kill it, including chlorine bleach or hydrogen peroxide.

If someone is sick, it’s important to use very hot water and bleach to destroy virus that could be on any clothing, sheets or towels.

People start spreading norovirus before they actually feel sick, and they can spread it for as long as two weeks after they start getting better.