Norovirus is commonly known as the “stomach flu,” despite the fact that it has nothing to do with influenza. Norovirus is a highly contagious infection that affects around 23 million Americans ever year. Of those 23 million, around 50,000 require hospitalization, and up to 500 will die. Norovirus causes the illness known as gastroenteritis.

The easiest way for a person to be exposed to noroviruses is through food and water contaminated by fecal matter. This usually occurs during the preparation of food. It is also possible to spread infection through close contact with someone who is infected. Unlike something like chickenpox, a person can catch norovirus infections multiple times in their life.

Norovirus is also referred to as calicivirus, viral gastroenteritis, acute gastroenteritis, non-bacterial gastroenteritis, and food poisoning.

Causes/Risks

The norovirus is responsible for gastroenteritis. Aside from being highly contagious, it can also stand up against heat, cold, and disinfectants. It travels through the feces of an infected person or animal to food or water. In some foods, such as oysters and fruits, the infection can attach itself at harvest.

Contamination of food can happen in various ways. An infected person handling food can inadvertently shed the virus through direct contact. If their hands contain particles of the infection, the work surface is contaminated, or even tiny drops of vomitus in the air come in contact with food, it will be contaminated. Food and drinks need less than 100 norovirus particles to be considered contaminated and able to infect a person. By comparison, a person will shed billions of the norovirus particles while infected.

A person becomes infected when they ingest norovirus found in contaminated food or drinks. They can also catch the virus by touching contaminated objects, then touching their mouth. In addition, direct contact with an infected person, such as sharing drinks or utensils, will result in infection. Generally, the virus stays in the stool for at least fourteen days, sometimes longer.

Because it spreads so easily and in vast quantities, norovirus gastroenteritis commonly causes outbreaks in places where food and water are consistently handled by an infected person. This commonly includes cruise ships, nursing homes, hospitals, restaurants, and schools.

Symptoms

Norovirus symptoms develop anywhere between a few hours to a few days after infection. A person with norovirus will experience nausea, vomiting, diarrhea, fever, abdominal pain, headaches, and weight loss. Because fluids are being lost so quickly, dehydration is a major consideration for people with norovirus.

Diagnosis/When to See a Doctor

Norovirus infection can often be identified just by observing a person’s symptoms. If symptoms last longer than two days or are more severe than normal, a doctor may perform a stool culture to identify the norovirus in feces. Additional tests are performed to rule out other causes for the symptoms. A rectal or abdominal exam can identify inflammatory bowel disease such as Crohn’s. A colonoscope can identify diseases such as ulcerative colitis.

It is more difficult to identify the cause of norovirus than to determine the virus itself, simply due to the ease of infection and number of ways contamination occurs.

Treatment

Unfortunately, there is no recommended treatment for norovirus. Antibiotics have no effect on viruses such as norovirus. Luckily, the body is generally strong enough to fight off the virus with the aid of rehydration. A person must drink plenty of fluids in order to replace what has been lost through diarrhea and vomiting. Food high in carbohydrates, such as potatoes, chicken, and whole grains can put much-needed nutrients back in the body.

It should be noted that children become dehydrated more quickly and must be treated with more care. Fluids can be given with a mixture of salts and sugar. Parents with infants experiencing symptoms such as vomiting and diarrhea should contact a doctor.

Complications

Norovirus will usually go away after a few days, but there are instances where it can become life threatening. Vomiting and diarrhea can cause dehydration if a person is not properly rehydrating. Dehydration causes weakness, dry mouth, and decreased frequency in urination.

Malnutrition can also occur, especially in children. Too much vomiting and diarrhea can also lower levels of potassium in the blood, leading to hypokalemia, which can cause death if untreated. Additionally, low levels of sodium will result in hyponatremia. Hyponatremia is the most common electrolyte disease in the United States, causing the cells to swell with water and can lead to coma and even death.

Prevention

A person may or may not know they are carrying the norovirus. Either way, it is important to practice prevention techniques to make sure the virus is not spread to others.

• Avoid preparing food. If you are experiencing symptoms, stay away from making food, especially for others. Restaurant workers are advised to not work for two to three days after they feel better. Preparing food while sick is an easy way to transfer the virus to others.
• Wash your hands. Because the virus spreads so many particles in the feces and vomitus, washing your hands with soap and water can reduce the risk of passing norovirus to others.
• Wash fruits and vegetables. It is possible for fruits, vegetables, and seafood such as oysters to already carry the norovirus. Knowing exactly where these food items have come from can help trace contamination. Washing them can reduce the risk. If any items are known to be contaminated, they should be thrown out immediately.
• Keep surfaces clean. A person who is sick comes in contact with many surfaces. Disinfecting counters, especially in the kitchen and bathroom, can go a long way to preventing the spread of norovirus. Chlorine and bleach solutions are most effective.
• Do the laundry. Washing clothes, linens, and bedding properly is important, but it is also important not to agitate these items in a manner that can spread the virus. Washing and drying can eliminate the infection.
• Do not share utensils or glasses with others. If you or someone you know has been recently infected with the norovirus, avoid close contact with items they have used. Never share utensils or glasses, as it is possible to transfer the disease through the mouth.