What is Norovirus and what are its symptoms?

Norovirus cases are on the rise in the United States, with 455 outbreaks reported since the start of September. More than 90 of these occurred in the first week of December – one of the highest rates reported in any week since records began in 2012.

The true number of outbreaks is likely far higher, as only 14 states contribute to the Centers for Disease Control and Prevention’s “NoroSTAT” reporting system.

Rising disease rates are also reflected in an increasing rate of positive tests for noroviruswhich the CDC uses to monitor the spread of the disease across the country. These saw a sharp increase from 10.6% in the week ending 16 November to 22.02% in the week ending 21 December. High case rates have also been reported in other countries, including the UK

About 2,500 outbreaks are usually reported each year in the United States, with the majority of cases occurring between November and March and peaking in February. Experts say the disease may take hold earlier this year as people socialize more easily than they have in years.

What is Norovirus?

Also known as the “stomach flu,” the “stomach bug,” and the “winter vomiting bug,” norovirus is a highly contagious seasonal illness that causes gastrointestinal symptoms. In fact, it is responsible for more vomiting and diarrhea and foodborne illness than any other disease in the country.

Norovirus is spread when small particles of infected feces enter the body through the mouth. It is often spread by direct contact with an infected person, touching a contaminated surface (and then the mouth), or by consuming tainted food or drink.

Inside the body, norovirus finds its way to the gut, where it latches onto sugars called “oligosaccharides” that line the small intestine. Once there, it can inflame the intestines or stomach, leading to severe gastrointestinal illness.

What are the symptoms of Norovirus?

Norovirus commonly causes nausea, abdominal pain, vomiting, and diarrhea. It can also lead to certain flu-like symptoms, such as headache, fever and body aches. Although it is often called the “stomach flu,” it is not caused by the influenza virus.

Vomiting and diarrhea can quickly cause dehydration, so people with the disease should try to drink water, even if it’s hard to keep it down. Taking very small, frequent sips of water can make it easier to stay hydrated.

Symptoms appear relatively quickly after exposure to norovirus—usually within about 12 to 48 hours, according to the CDC. They usually end one to three days later. But a person can still spread the disease through their stool for days after they feel better.

How can I protect myself from Norovirus?

The best way to prevent norovirus is by frequent, thorough hand washing—especially after using the bathroom, changing a baby or caring for someone with the disease, and before eating. Try to avoid touching your face as this can bring the virus closer to your mouth.

Keep touch-sensitive surfaces such as doorknobs and countertops clean, and wash clothing and sheets that may be contaminated at high temperature to kill any lingering viruses.

It’s also important to wash fruit and vegetables before eating them, and make sure to cook seafood thoroughly. The CDC recommends avoiding raw shellfish like oysters altogether, as it can lead to illness and even death.