Norovirus: Types, Symptoms, Causes, Diagnosis, and Treatment


According to Everyday Health norovirus is a virus that affects the stomach and intestine and spreads easily from person to person. It’s highly contagious and can quickly pass between people, especially in places like hospitals, schools and day care centers.

What is Norovirus?

Most people have experienced it at some point. It’s a common illness that can also come from eating contaminated food. The symptoms usually include vomiting and diarrhea which start within a day or two of being exposed and can last for a few days. Most people recover fully on their own but dehydration can be a concern, especially for young children, older adults and those with health issues. There’s no specific treatment for it other than resting and drinking fluids to stay hydrated. Washing hands thoroughly and often can help reduce the risk of spreading the virus. Norovirus is a leading cause of stomach and intestinal infections worldwide, causing millions of cases each year. In the United States alone, it’s responsible for millions of illnesses annually.

What are the Types of Norovirus?

It is a diverse group of viruses, and there are many different strains or genotypes of  it. Currently, there are at least seven genotypes of it (GI to GVII), which are further divided into multiple genotypes and variants. The most common genogroups that cause illness in humans are GI, GII and GIV. Within each genogroup, there are multiple genotypes and variants each with slightly different genetic characteristics. The different genotypes and variants of it contribute to the variability in symptoms, transmission, patterns, and immunity among affected individuals. It’s important to note that while there are many types of norovirus, they all cause similar symptoms of gastroenteritis, including vomiting, nausea, diarrhea and stomach cramps.

What are the Symptoms of Norovirus?

The symptoms of norovirus infection typically include:

  • Vomiting
  • Nausea
  • Diarrhea
  • Stomach cramps
  • Low-grade fever
  • Headaches
  • Body aches
  • Fatigue

These symptoms usually appear within 12 to 48 hours after exposure to the virus and can last for 1 to 3 days. In some cases, individuals may also experience dehydration due to vomiting and diarrhea, which can be serious especially in young children, older adults, and individuals with weakened immune systems. It’s important to stay hydrated and seek medical attention if dehydration or severe symptoms occur. This can lead to dehydration. Symptoms of dehydration include:

  • Dizziness when standing up
  • Dry mouth
  • Dry throat
  • Decrease in urination

What are the  Causes of Norovirus?

It is caused by a virus belonging to the Caliciviridae family. When this virus enters the body it leads to inflammation or swelling of the stomach and intestines, a condition known as gastroenteritis. The inflammation is responsible for the symptoms associated with it.

What are the Risk Factors of Norovirus?

The risk factors of it include:

Contact with Infected Individuals:

You are more likely to get it if you come into contact with someone who is infected with the virus. This can occur through direct contact with an infected person or by touching surfaces or objects contaminated with the virus.

Genetic Susceptibility:

Some individuals may be more genetically susceptible to developing symptoms of it compared to others. This means that certain genetic factors may influence an individual’s likelihood of experiencing symptoms after being exposed to the virus. Overall, while anyone can get it these risk factors can increase the likelihood of becoming infected or developing symptoms after exposure to the virus.

What is the Diagnosis and Tests of Norovirus?

Diagnosis of this infection is usually based on the symptoms reported by the patient, along with a history of exposure to the virus such as contact with an infected individual or recent consumption of contaminated food or water. In some cases, healthcare providers may order tests to confirm this infection especially in outbreaks or severe cases.

Stool Sample Analysis:

A stool sample may be collected and tested in a laboratory to detect the presence of its genetic material or antigens. This test can help confirm the diagnosis of norovirus infection.

Polymerase Chain Reaction (PCR) Test:

PCR testing is a highly sensitive method used to detect norovirus genetic material in stool samples. This test can accurately identify the specific strain of norovirus present in the sample.

Enzyme Immunoassay (EIA) Test:

EIA testing is a rapid diagnostic test that detects norovirus antigens in stool samples. This test provides quick results and is often used in outbreak settings to identify cases of norovirus infection.

Electron Microscopy:

It may be used to visualize norovirus particles in stool samples. While less commonly used than molecular tests, electron microscopy can provide direct visualization of the virus. It’s important to note that norovirus diagnosis is primarily based on clinical symptoms, and laboratory testing may not always be necessary especially in mild cases. Treatment is usually supportive, focusing on managing symptoms such as dehydration and providing fluids and electrolytes as needed.

What is the Treatment of Norovirus?

Management and treatment of norovirus infection primarily focus on relieving symptoms and preventing dehydration. Here are some key aspects of management and treatment.

Fluid Replacement:

Replacing fluids lost through vomiting and diarrhea is essential to prevent dehydration. Oral rehydration solutions (ORS) containing electrolytes and water can help replace lost fluids and electrolytes. In severe cases of dehydration intravenous (IV) fluids may be necessary.

Rest and Symptoms Relief:

Getting plenty of rest and avoiding solid foods until vomiting and diarrhea have subsided can help the body recover. Over-the counter medications such as antiemetic (to reduce the nausea and vomiting) and antidiarrheal (to reduce diarrhea) may provide symptoms relief but they should be used with caution especially in children and older adults.

Hygiene Measure:

Practicing good hygiene is important to prevent the spread of norovirus to others. This includes frequent handwashing with soap and water especially after using the bathroom or changing diapers, and disinfecting contaminated surfaces and objects.

Isolation and Quarantine:

Individuals with norovirus infection should stay home from work, school, or other public places until at least 48 hours after their symptoms have resolved to prevent spreading the virus to others. Caregivers should also take precautions to avoid spreading the virus to vulnerable individuals.

Seeking Medical Attention:

While norovirus infections are usually mild and self-limiting, it’s important to seek medical attention if symptoms are severe, if dehydration occurs, or if there are concerns about complications. Healthcare providers may offer supportive care and monitor for complications, especially in vulnerable populations such as young children, older adults, and individuals with weakened immune systems. The management of norovirus infection focuses on supportive care to relieve symptoms and prevent dehydration along with hygiene measures to prevent the spread of the virus to others.


Don’t push yourself, Stay at home and rest.

Continue Your Diet:

Infants should continue breastfeeding or formula feeding while being rehydrated. For children and adults as appetite pick up, some good choices are:

  • Soups
  • Plain noodles
  • Rice
  • Pasta
  • Eggs
  • Potatoes
  • Crackers or bread
  • Fresh fruits
  • Yogurt
  • Jell-O
  • Cooked vegetables
  • Lean protein like chicken and fish

What are the Complications of Norovirus?

The complications of norovirus infection are typically related to dehydration which can occur due to vomiting and diarrhea. Dehydration can lead to:

Electrolyte Imbalance:

Vomiting and diarrhea can lead to the loss of electrolytes such as sodium, potassium, and chloride, which are essential for proper bodily function. An electrolyte imbalance can result in symptoms such as weakness, dizziness, and irregular heartbeat.


Loss of fluids through vomiting and diarrhea can lead to dehydration especially in young children, older adults and individuals with weakened immune systems. Symptoms of dehydration include excessive thirst, dry mouth, decreased urine, output, and lethargy.

Complications in Vulnerable Populations:

In vulnerable populations such as young children, older adults, and individuals with underlying health conditions, these infections can lead to more severe complications, including hospitalization and in rare cases, death. These individuals may be at higher risk of developing severe dehydration and other complications due to their age or health status. Overall, while this infection is typically mild and self-limiting in healthy individuals, complications can occur, especially in vulnerable populations if dehydration is not adequately managed. It’s essential to seek medical attention if dehydration or severe symptoms develop.

What is the Prevention of Norovirus?

The best way to prevent the spread of foodborne norovirus is by practicing proper food handling. Good handle hygiene and food cleaning are essential for preventing norovirus transmission. Noroviruses can survive freezing temperatures and even high heat. Some people may get infected after consuming steamed shellfish. The virus can linger on countertops and serving utensils for up to 2 weeks and is resistant to many hand sanitizers and disinfectants. Despite these survival traits, experts suggest that simple personal and food hygiene measures can significantly reduce norovirus transmission. Here are some steps to reduce the risk of norovirus infections:

  • Handwashing
  • Cleaning surfaces
  • Avoiding risky foods
  • Removing infected feces and vomit
  • Washing clothes and bedclothes
  • Keeping the toilet set down
  • Staying at home
  • Using disposable towels
  • Taking care when traveling

Hospitals and other healthcare facilities also play a crucial role in preventing norovirus transmission. They should implement strategies to limit the spread of the virus, such as isolating individuals with an infection.

Norovirus in Babies:

Babies and toddlers are more vulnerable to norovirus, a highly contagious stomach and intestinal virus. They’re at higher risk for serious complications compared to healthy adults. Symptoms in infants and children may include:

  • Irritability of fussiness
  • Sleepiness
  • Vomiting
  • Diarrhea

There’s a serious risk of dehydration due to vomiting and diarrhea. Babies can’t tolerate as much vomiting and diarrhea as adults. Contact your pediatrician if your child:

  • Is under 6 months old and experience vomiting or diarrhea
  • Has had six or more watery stools in 24 hours
  • Has vomited three times or more in 24 hours
  • Has pale or mottled skin,
  • Sunken eyes, or isn’t producing tears
  • Has a fever
  • Has a bloody diarrhea
  • Has a coexisting health problem
  • Has a fever is lethargic or complains of dizziness
  • Produces little to no urine or has had symptoms lasting two days

Worldwide, about 200 million norovirus cases occur yearly in children under age 5. In the United States over one million medical visits for children due to norovirus. Approximately, 1 in 278 children will need hospital care for norovirus by their fifth birthday with 1 in 14 needing emergency room care and 1 in 6 needing outpatient care. Norovirus spreads quickly among children so infected children should avoid school, day care, and other activities. Children should be taught to wash their hands frequently, especially after using the bathroom.

Norovirus During Pregnancy:

If you get norovirus while pregnant, it typically won’t harm your baby or your long-term health. However, if you experience diarrhea and vomiting during pregnancy, it’s important to note that contact your doctor promptly. While it may be norovirus, it could be another condition. Preventing dehydration is crucial as it can be a serious complication of norovirus. If you’re vomiting or have diarrhea, drink plenty of fluids like Pedialyte, but avoid beverages containing caffeine. Always consult your doctor before taking any over-the-counter medications during pregnancy. If you experience signs of dehydration. Such as:

  • Dark colored urine
  • Decreased urination
  • Dry mouth
  • Dry throat
  • Lightheadedness
  • Dizziness
  • Loss of appetite
  • Fatigue
  • Rapid heartbeat
  • Headaches

Are Norovirus Symptoms the Same in Children and Adults?

While the symptoms of norovirus infection are generally similar in both children and adults, there can be some differences in how the symptoms manifest:

  • Vomiting
  • Diarrhea
  • Severity

Overall, while there may be slight differences in the prevalence and severity of specific symptoms between children and adults, the hallmark symptoms of norovirus infection including vomiting, diarrhea, nausea, and stomach cramps, are generally consistent across age groups.

Recurring Norovirus:

Recurring norovirus or experiencing norovirus multiple can be challenging and frustrating. While most people develop immunity to a specific strain of norovirus after infections, it’s possible to be infected with different strains over time. Here are some factors to consider if you’re experiencing recurring norovirus. Such as:

  • Immunity
  • Reinfection
  • Immune system
  • Hygiene practices
  • Food Safety

If the norovirus is spreading in your family or workplace, take steps to reduce the risk of reinfection:

  • Wash your hands thoroughly and frequently, especially after using the toilet, changing diapers or caring for a sick individual. Wash hands before preparing or eating food. Use an alcohol-based hand sanitizer if soap and water are unavailable.
  • Avoid touching your face with your hands.
  • Refrain from sharing eating utensils, cups, or plates.
  • Wash fruits and vegetables before consuming them.
  • Steer clear of raw seafood.
  • Whenever possible, avoid close contact with infected individuals. Stay home if you’re feeling unwell.
  • If you frequently experience vomiting or diarrhea, consult your doctor to confirm if it’s due to norovirus. They may conduct a stool sample test for diagnosis.

What is the Recovery Time of Norovirus?

Norovirus symptoms typically start kicking in around 12 to 48 hours after you’ve been exposed to the virus. For healthy adults, it’s usually not too serious and symptoms last for about one to three days before you start feeling better. However, babies can have a tougher time with norovirus. They may experience more vomiting and diarrhea, which can lead to dehydration. It’s important to give them oral rehydration solutions like Pedialyte to replenish lost fluids. In severe cases, they might need IV fluids and other treatments and their recovery time may be longer. If you have a weakened immune system or other health issues, it might take longer for you to bounce back from norovirus. Sadly, norovirus is a significant cause of death for children in developing countries, with about 50,000 young lives lost each year. Other adults especially those with chronic illnesses are also at risk.

Is Norovirus Contagious?

Yes, it is highly contagious meaning it spreads easily from person to person. When someone is infected with it their body releases billions of tiny virus particles that can make others ill. It only takes a few of these particles to infect someone else. After being exposed to norovirus it can take 12 to 48 hours for symptoms to appear. This period before symptoms develop is called the incubation period. Even after symptoms stop, infected individuals can still be contagious for up to 48 hours, meaning they can contribute to spreading the virus to others during this time.

What is the Difference Between Norovirus and Stomach Flu?

Norovirus and the stomach flu are terms that are often used interchangeably, but they refer to different things.


It is a specific type of virus that causes gastroenteritis which is inflammation of the stomach and intestine. It is highly contagious and spreads easily through direct or indirect contact with an infected person, contaminated surfaces or contaminated food or water. Norovirus are characterized by symptoms such as vomiting, diarrhea, nausea, stomach pain, cramps, and sometimes fever. It is a common cause of outbreak of gastroenteritis in settings like schools, cruises, ships, and hospitals.

Stomach Flu:

The term “stomach flu” is a bit of a misnomer because it’s not actually caused by the influenza virus which is responsible for seasonal flu. Instead “stomach flu” is a colloquial term used to describe a viral infection that causes symptoms similar to those of gastroenteritis, such as vomiting, diarrhea, nausea, and stomach cramps. The viruses that can cause stomach flu include norovirus, rotavirus, and certain strains of adenovirus. Unlike the flu which primarily affects the respiratory system, stomach flu primarily affects the gastrointestinal system.


Is norovirus treated with antibiotics?

No, antibiotics are not effective in treating norovirus infections. Antibiotics are designed to fight infections, not viruses like norovirus.

What is the best anti-diarrhea medicine for norovirus?

Some adults may find relief from their symptoms by taking loperamide (Imodium A-D) or bismuth subsalicylate (Pepto-Bismol, others). These medications can help manage symptoms associated with norovirus such as diarrhea.

What foods cause norovirus?

Foods that are commonly involved in norovirus outbreaks include leafy greens like lettuce. Outbreaks can also occur from food that is contaminated at the source or on the farm, such as oysters harvested from contaminated water, or fruit and vegetables sprayed with contaminated water in the field.

What fruit is good for norovirus?

For individuals suffering from it or expanding diarrhea the BRAT (banana, rice, apples and toast) diet is often recommended. Along with these foods other mild options that can help ease the gastrointestinal tract include saltines, oatmeal, and boiled potatoes. These foods are gentle on the stomach and may provide relief from symptoms.

Are eggs good for norovirus?

Soda crackers, toast, plain noodles, gelatin, eggs, applesauce, and banana are recommended as good first food choices for individuals with norovirus. It’s advisable to avoid acidic, spicy, fatty, or fibrous foods such as meats, coarse grains, and vegetables.

What foods stop diarrhea?

When experiencing diarrhea, it’s recommended to eat simple, easy to digest foods. Some of these include:

  • Oatmeal
  • Bananas
  • Plain rice
  • Applesauce
  • Boiled potatoes
  • Toast
  • Plain crackers
  • Pretzels
  • Baked chicken without skin or fat

Is an apple good for diarrhea?

Yes, apples can be beneficial for managing diarrhea. They contain both soluble and insoluble fiber, with insoluble fiber making up about 64% and soluble fiber about 36% of the fruit. Soluble fiber helps to form a gel-like consistency in stools and slow down digestion. This can help regulate bowel movements and provide relief from diarrhea.

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