If you’ve ever had a “stomach bug,” chances are you had norovirus.
The good news is that your body usually eradicates this virus after a few days. The bad news, however, is that the virus is extremely contagious and wreaks havoc on your body while it’s in your system.
Read on for more details on transmission, treatment, and prevention.
What Is Norovirus?
Norovirus is a highly contagious virus that can cause gastrointestinal symptoms such as nausea, vomiting, and diarrhea in infected people.
People who have norovirus illness may call it “a stomach bug,” “the stomach flu,” or even food poisoning. However, it is not actually the flu, and other factors beyond contaminated food can cause norovirus illness.
Anyone — adults or children — can contract norovirus. It causes a condition called acute gastroenteritis, which is an inflammation of your stomach or intestines. As a result, you experience gastrointestinal symptoms.
“Norovirus is the most common cause of epidemic viral gastroenteritis in the world,” says Shane Eikenberry, MD, Greater Pittsburgh Medical Associates-UPMC.
Norovirus infection is very common. According to the Centers for Disease Control and Prevention (CDC), the virus causes 19 million to 21 million illnesses in the United States each year. It is the leading cause of foodborne illness in the U.S.
Outbreaks of norovirus are common because the virus spreads so easily and quickly. According to the CDC, the illness occurs most often between November and April.
A person with norovirus infection is contagious mainly when they have symptoms and a few days after they improve. However, they can still spread the virus for two weeks or more after being healthy.
People with norovirus typically can recover at home. However, the CDC reports that norovirus infections cause about 109,000 hospitalizations, 465,000 emergency department visits, and 2.27 million outpatient clinic visits each year in the United States. About 900 people die from norovirus each year, mostly adults over 65 years old.
How Does Norovirus Spread?
Norovirus travels in microscopic particles of feces or vomit from an infected person. Contaminated particles can make their way into your mouth accidentally, and just a few contaminated particles can make you sick.
You can get norovirus illness through close contact with someone who’s sick, consuming contaminated food or water, or touching a contaminated surface and then touching your mouth.
Direct contact
Being in close contact with someone who has norovirus can cause you to get infected yourself. If you’re caring for someone who’s sick, you may inadvertently ingest tiny particles of vomit or feces. Those particles also could get on your hands, and if you later touch your mouth, you can get infected.
Sharing food or utensils with someone who is infected or eating food prepared by them can also cause you to get infected.
Direct contact causes most cases of norovirus transmission, the CDC says.
Contaminated food or water
Consuming contaminated food or water can cause you to get infected with norovirus.
If a person infected with norovirus touches food with their bare hands and you later consume it, you can become infected yourself. Food can also become contaminated if it touches a contaminated surface.
Foods that grow in contaminated water — such as shellfish — or foods watered with contaminated water, like fruits and vegetables, can also be contaminated. You may get infected with norovirus if you don’t properly wash and prepare those foods.
Water can become contaminated through leakage from a septic tank or if it is not properly treated. It can also become contaminated when someone with norovirus vomits or defecates into it. Consuming contaminated water or foods touched with contaminated water can make you sick.
Contaminated surfaces
Tiny contaminated fecal or vomit particles from someone with norovirus infection can land on surfaces, contaminating them. People who have norovirus can also contaminate a surface if they touch it with their bare hands.
If you touch a contaminated surface and then your mouth, you can get infected with norovirus yourself. Food or other objects can also touch the contaminated surface; you can get infected if you touch these objects and then your mouth.
Particles contaminated with norovirus are extremely hardy; they can survive for up to two weeks on surfaces.
Norovirus Symptoms
The illness primarily affects your stomach, causing gastrointestinal symptoms like nausea, vomiting, and diarrhea. It also can cause whole-body symptoms.
Common symptoms of norovirus illness include:
- Body aches
- Diarrhea
- Fever
- Headache
- Nausea
- Stomach pain
- Vomiting
If you are experiencing these symptoms, it’s a good idea to stay home from work, monitor your symptoms, and drink plenty of fluids. Excess vomiting and diarrhea can cause dehydration, a common complication of norovirus infection.
Symptoms typically go away in one to three days.
Norovirus symptoms are typically most severe in children under 5, older adults, and people with other health conditions.
How Is Norovirus Treated?
There is no specific norovirus treatment or medication. Antibiotics do not help because they only treat bacterial illnesses, not viral illnesses. The best way to treat norovirus is to treat your symptoms.
If you have the virus, your doctor will likely recommend drinking fluids to replace the fluids lost through vomiting and diarrhea and prevent dehydration.
Severe dehydration is dangerous and can require hospitalization. If this happens, health care professionals will administer fluids intravenously to rehydrate your body as quickly as possible. Signs of dehydration include:
- Crying with few or no tears.
- Decreased urination.
- Dizziness or fainting.
- Fussiness.
- Rapid heartbeat.
- Sleepiness.
- Very dark urine.
If you or someone you know has signs of severe dehydration, contact your doctor right away.
How to Prevent Norovirus
There is no vaccine to prevent norovirus, but you can take some key steps to avoid getting sick. Those include:
- Maintaining good hand hygiene — Wash your hands frequently with soap and water, scrubbing for at least 20 seconds before rinsing. This is most important before and after caring for someone with norovirus, after using the bathroom, and before handling food. Hand sanitizer is not a good substitute for soap and water to prevent norovirus.
- Preparing food safely — Thoroughly rinse raw fruits and vegetables before eating them. Cook oysters and other shellfish to an internal temperature of at least 145 F, and do not let raw oysters touch other food items. Make sure you clean cutting boards, utensils, and counters after preparing food — especially raw fruits and vegetables and shellfish.
- Sanitizing surfaces — Clean and sanitize surfaces after someone vomits or has diarrhea on them. Remember that tiny particles can land on nearby surfaces, so clean those as well. Wear rubber or disposable gloves and wipe the area with paper towels. Sanitize the area with a bleach-based disinfectant. It’s best to use a bleach-based product with a concentration of 1,000 to 5,000 ppm or a product registered with the Environmental Protection Agency (EPA) to prevent norovirus. Leave the disinfectant on the surface for at least five minutes before washing it again with soap and hot water. Throw away any trash afterward.
- Washing laundry — Immediately remove and wash any clothing, bed linens, or other items that may have vomit or feces on them. Wear disposable or rubber gloves to handle the items. Use hot water, detergent, and your washing machine’s highest cycle setting to wash the items. Dry them with high heat.
If you have norovirus illness, stay home from work, school, and social activities while you’re sick and for two to three days afterward. Do not make food for anyone for two to three days after your symptoms end to protect them from the sickness. Remember that you can be contagious for up to two weeks after your symptoms go away, so caution is key.
If you are sick and need care, contact the specialists at UPMC Primary Care. Our providers offer wellness services and care for both common and complex medical conditions. They can also examine your condition and provide assistance or refer you to urgent care if necessary. To find a UPMC primary care doctor near you, call 1-855-676-8762 or visit our website.
Editor's Note: This article was originally published on , and was last reviewed on .