Viral gastroenteritis (stomach flu) – Symptoms and causes

Overview

Viral gastroenteritis is an intestinal infection that includes signs and symptoms such as watery diarrhea, stomach cramps, nausea or vomiting, and sometimes fever.

The most common way to develop viral gastroenteritis often called stomach flu is through contact with an infected person or by consuming contaminated food or water. If you're otherwise healthy, you'll likely recover without complications. But for infants, older adults and people with compromised immune systems, viral gastroenteritis can be deadly.

There's no effective treatment for viral gastroenteritis, so prevention is key. Avoid food and water that may be contaminated and wash your hands thoroughly and often.

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The stomach, small intestine and large intestine (colon) are part of your digestive tract, which processes the foods you eat. Viral gastroenteritis is an inflammation of these organs caused by a virus.

Although it's commonly called stomach flu, gastroenteritis isn't the same as influenza. The flu (influenza) affects only your respiratory system your nose, throat and lungs. Gastroenteritis, on the other hand, attacks your intestines, causing signs and symptoms such as:

Depending on the cause, viral gastroenteritis symptoms may appear within 1-3 days after you're infected and can range from mild to severe. Symptoms usually last just a day or two, but occasionally they may last up to 14 days.

Because the symptoms are similar, it's easy to confuse viral diarrhea with diarrhea caused by bacteria, such as Clostridioides difficile, salmonella and Escherichia coli, or parasites, such as giardia.

If you're an adult, call your health care provider if:

See your child's health care provider right away if your child:

If you have an infant, remember that while spitting up may be an everyday occurrence for your baby, vomiting is not. Babies vomit for a variety of reasons, many of which may require medical attention.

Call your baby's doctor right away if your baby:

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You're most likely to get viral gastroenteritis when you eat or drink contaminated food or water. You may also be likely to get gastroenteritis if you share utensils, towels or food with someone who has one of the viruses that cause the condition.

Many viruses can cause gastroenteritis, including:

Noroviruses. Both children and adults are affected by noroviruses, the most common cause of foodborne illness worldwide. Norovirus infection can sweep through families and communities. It's especially likely to spread among people in confined spaces.

In most cases, you pick up the virus from contaminated food or water. But it can also spread between people who are in close contact or who share food. You can also get the virus by touching a surface that's been contaminated with norovirus and then touching your mouth.

Rotavirus. Worldwide, this is the most common cause of viral gastroenteritis in children, who are usually infected when they put their fingers or other objects contaminated with the virus into their mouths. It can also spread through contaminated food. The infection is most severe in infants and young children.

Adults infected with rotavirus may not have symptoms, but can still spread the illness. This is of particular concern in institutional settings such as nursing homes because adults with the virus unknowingly can pass the virus to others. A vaccine against viral gastroenteritis is available in some countries, including the United States, and appears to be effective in preventing the infection.

Some shellfish, especially raw or undercooked oysters, also can make you sick. Contaminated drinking water is a cause of viral diarrhea. But in many cases the virus is passed when someone with a virus handles food you eat without washing his or her hands after using the toilet.

Gastroenteritis occurs all over the world and can affect people of all ages.

People who may be more susceptible to gastroenteritis include:

Each gastrointestinal virus has a season when it's most active. If you live in the Northern Hemisphere, for instance, you're more likely to have rotavirus or norovirus infections in the winter and spring.

The main complication of viral gastroenteritis is dehydration a severe loss of water and essential salts and minerals. If you're healthy and drink enough to replace fluids you lose from vomiting and diarrhea, dehydration shouldn't be a problem.

Infants, older adults and people with weakened immune systems may become severely dehydrated when they lose more fluids than they can replace. Hospitalization might be needed so that lost fluids can be replaced through an IV in their arms. Dehydration can rarely lead to death.

The best way to prevent the spread of intestinal infections is to follow these precautions:

Wash your hands thoroughly. And make sure your children do, too. If your children are older, teach them to wash their hands, especially after using the toilet.

Wash your hands after changing diapers and before preparing or eating food, too. It's best to use warm water and soap and to rub hands well for at least 20 seconds. Wash around cuticles, beneath fingernails and in the creases of the hands. Then rinse thoroughly. Carry sanitizing wipes and hand sanitizer for times when soap and water aren't available.

When you're traveling in other countries, you can become sick from contaminated food or water. You may be able to reduce your risk by following these tips:

Jan. 18, 2022

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Viral gastroenteritis (stomach flu) - Symptoms and causes