What Is Norovirus? 5 Things To Know


Hundreds of students in Sacramento and Yolo counties have come down with norovirus, a highly contagious gastrointestinal illness, in recent days.

Yolo County health officials report 2,091 cases of norovirus, while Sacramento County has seen suspected cases in six school districts. Here’s some more information on the virus:

Noroviruses are the most common cause of acute stomach and intestinal infections in the United States, reports the U.S. Food and Drug Administration. It’s also sometimes called stomach flu, viral gastroenteritis or the winter vomiting bug. The U.S. reports 19 million to 21 million cases a year. Humans are the only hosts of the virus.

The virus was formerly known as the Norwalk virus, because the first known outbreak took place at an elementary school in Norwalk, Ohio, according to norovirus.com. Scientists identified the virus in 1972 from stool samples stored after the outbreak. It was officially renamed norovirus by the International Committee of Taxanomy of Viruses in 2002.

It’s extremely contagious. The Centers for Disease Control cautions that norovirus can be transmitted by infected people, contaminated food or water, or just by touching contaminated surfaces. People with norovirus are most contagious during the illness and for a few days afterward, and the virus can remain in stool for up to two weeks after the illness. The virus can survive temperature extremes, too.

Also, catching norovirus doesn’t help you fight it off later, in part because there are many different types of noroviruses – catching one doesn’t protect you from the others.

Diarrhea, cramps and vomiting usually start within 12 to 48 hours of exposure to the virus, says the Mayo Clinic. Norovirus symptoms normally last one to three days, and most people recover without treatment. But infants, older adults and people with chronic illnesses may require medical attention for dehydration.

Since it’s a virus, antibiotics aren’t any help, and there are no antiviral drugs for noroviruses.

The Mayo Clinic advises that people with norovirus take special care to replace fluids lost by vomiting or diarrhea to prevent dehydration. Drinks like Pedialyte are good for young children, while sports drinks and broths are suggested for adults.

But sugary drinks, like sodas and fruit juices, can make diarrhea worse, while alcohol or caffeinated drinks can speed dehydration.

Soup, bananas, yogurt and broiled vegetables are good choices to help reduce vomiting.

Good hygiene is the key to avoiding noroviruses. Wash your hands frequently with soap and water, particularly after using the bathroom and before preparing food. Alcohol-based cleaners are not as effective. The site also advises carefully throwing away contaminated items, such as dirty diapers.

Wash raw fruits and vegetables, and cook oysters and other shellfish thoroughly. Clean and disinfect surfaces with a mixture of detergent and chlorine bleach after someone’s sick, WebMD says. And if you have norovirus, don’t prepare food for at least two to three days after you feel better.

Cruise ships, nursing homes, daycare centers and, of course, schools are common breeding grounds for norovirus – anywhere large numbers of people are packed in close quarters, basically, reports the CDC. Outbreaks on cruise ships frequently make the news – 90 passengers reportedly fell ill on the Sun Princess in Australia in February – and there are countless travel websites dedicated to tracking cruise lines with the worst records for the illness.