Joanna Bisgrove, MD, was 35 weeks pregnant when she came down with a case of the contagious norovirus, sometimes called the stomach flu.
She’s certain she caught it from a family friend who was recently sick and used Dr. Bisgrove’s bathroom during a visit.
“She was still shedding virus even though she didn't realize that. I wasn’t home and didn't realize she had been there, so I didn't think to clean the [toilet] seat when I got home a few hours later. I had asked her to stay home, but her husband said ‘Hey, you’re fine now. Come along.’”
Twenty-four hours later, Dr. Bisgrove was ill. “And when you're 35 weeks pregnant, sick—throwing up, vomiting, diarrhea—which are the common symptoms of norovirus. It's not fun,” she said during an “AMA Update” episode on signs, symptoms and treatment for norovirus.
Dr. Bisgrove is a family physician with Rush University Medical Center and a member of the AMA Council on Science and Public Health. The medical center is part of the Rush University System for Health, which is a member of the AMA Health System Program that provides enterprise solutions to equip leadership, physicians and care teams with resources to help drive the future of medicine.
Norovirus causes about 2,500 reported outbreaks in the U.S. each year, according to the Centers for Disease Control and Prevention. At its most concentrated, it typically circulates from November to April. Norovirus outbreaks surged earlier this year, with 201 reported the week of Jan. 23, nearly four times the figure for the same week in 2024. The reality, however, is that norovirus can happen any time of year, noted Dr. Bisgrove, who spoke more about the virus’ presentation and what patients can do to reduce exposure and treat symptoms.
What it is, how it spreads
Norovirus is a virus that transmits through the fecal-oral route, meaning that a person can get sick if they come into contact with contaminated stool or vomit or contaminated surfaces. Unlike measles or influenza, it is not spread through the air.
“The main thing norovirus has in common with measles and the flu is how contagious it is,” said Dr. Bisgrove. “It's a little bugger that can live on surfaces for quite a long time.” Often this happens in food settings like restaurants, either because people don’t wash their hands or clean surfaces properly with high-grade disinfectants.
Someone who’s been sick can also shed the virus for a long period after symptoms resolve. The most concentrated time of norovirus shedding after someone feels better is about 48 hours, which means they are still highly likely to spread it.
Duration is often 2 to 3 days
Norovirus is a clinical diagnosis that factors in symptoms, potential exposure to something, and who the infected person recently interacted with.
While norovirus symptoms can mirror food poisoning, it usually lasts longer than 24 hours, whereas food poisoning is often very short in duration.
The family friend who exposed Dr. Bisgrove to norovirus hadn’t had any deli meat before her illness, which is often linked to listeria, a type of food poisoning. “The symptoms were about two or three days for her, so we knew that, most likely, clinically speaking, it was norovirus,” she said.
People typically don’t test to see if they have norovirus. If symptoms persist after a week or so, go and get tested, she advised. “Norovirus and other viruses frequently don't act like that. It is obnoxious, but it's quick.”
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Drink fluids, check your urine
Treatment for norovirus mainly involves supportive care. Drink fluids often and check for symptoms of lightheadedness and dark or small amounts of urine.
If the urine starts looking dark or red, or it’s not coming out, or if you're vomiting and can't keep fluids down, then it’s time to seek medical attention. “That's when you need to go in and get checked out, because they may need to give you fluids through the IV [and] some anti-nausea meds to help keep your body functioning properly until the illness passes,” said Dr. Bisgrove.
Patients should also seek clinical assistance if symptoms persist beyond seven to 10 days, to rule out a bacterial infection that isn’t norovirus. “We'll start asking a lot more questions. Have you traveled, have you eaten raw sushi, or other raw foods?” she noted.
Prevention starts with washing hands
Washing hands and keeping surfaces clean with high grade disinfectants are two ways to keep norovirus from spreading.
Wash your hands for at least 20 seconds, said Dr. Bisgrove. “For children, we often talk about singing happy birthday two times while you're washing your hands. Hand sanitizer doesn't work as well.”
Infection spreads in the food setting because food workers who are sick often come back too soon, and surfaces aren't being cleaned. “We frequently recommend if you are sick, stay home for at least 48 hours after the symptoms are gone,” she advised.
Dr. Bisgrove recently used this knowledge to prevent her elderly father from getting sick.
“My father asked me recently if he could go to lunch with some friends who had just been sick. And the other man possibly had norovirus. And I said to wait at least 48 hours just in case, because my dad's about to turn 85 this year. We don't want him getting that sick.”
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