Viral gastroenteritis (stomach flu)
Gastroenteritis is an infection of the intestine that includes symptoms such as diarrhea, stomach cramps, nausea and vomiting, and fever.
If you are otherwise healthy, you will likely recover from a case of viral gastroenteritis. But for infants, older adults, and people with weakened immune systems, the illness can be more severe and lead to complications. People with compromised immune systems are at a higher risk for viral gastroenteritis, which can be deadly.
There is no effective treatment for viral gastroenteritis, so prevention is key. Avoid food and water that may be contaminated and always wash your hands thoroughly and often.
Symptoms
Gastroenteritis is not the flu. The flu affects only your respiratory system - your nose, throat, and lungs. Gastroenteritis, on the other hand, attacks your intestines, causing signs and symptoms such as:
- Diarrhea that is usually watery is not usually a sign of a more serious infection. If diarrhea is bloody, it means you have a more severe infection.
- Nausea, vomiting or both
- Stomach cramps and pain can be very uncomfortable.
- Occasional muscle aches or headache
- Low-grade fever
Viral gastroenteritis symptoms will typically appear within 1-3 days after you become infected and can range from mild to severe. Symptoms usually last only a day or two, but occasionally they may last up to 14 days.
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.
When to see a doctor
If you are an adult and have any health concerns, please call your health care provider.
- It will be difficult for you to keep down liquids for more than 24 hours.
- You have been sick for more than two days, and you've been vomiting or having diarrhea.
- You're vomiting blood
- You are dehydrated — these signs may include excessive thirst, dry mouth, deep yellow urine, or little or no urine. You may also experience dizziness or lightheadedness.
- You notice blood in your bowel movements
- You have severe stomach pain
- You have a fever above 104 F (40 C)
For infants and children
If you notice any changes in your child's health, make sure to see his or her health care provider right away.
- Has a fever of 102 F (38.9 C) or higher
- Seems tired or very irritable
- Is in a lot of discomfort or pain
- Has bloody diarrhea
- It seems like the child is dehydrated - watch for signs of dehydration such as a dry mouth, thirst, and crying without tears in sick infants and children.
Babies may vomit often, but vomiting is not always a sign of a problem. Vomiting can be caused by a variety of reasons, some of which may require medical attention.
If you notice anything wrong with your baby, such as fever, rash, or trouble breathing, call your doctor right away.
- Has vomiting that is frequent
- Hasn't had a wet diaper in six hours
- Has bloody stools or severe diarrhea
- The fontanel is a soft spot on the top of his or her head.
- Has a dry mouth or cries without tears
- Is feeling very sleepy or drowsy.
Causes
You are most likely to get viral gastroenteritis if you eat or drink contaminated food or water. This can also happen if you share utensils, towels, or food with someone who has one of the viruses that cause the condition.
A variety of viruses can cause gastroenteritis, including:
Noroviruses.Noroviruses can affect both children and adults. This virus is the most common cause of foodborne illness worldwide, and it is liable to spread rapidly among people in close quarters.
The virus is usually picked up from contaminated food or water. But it can also spread between people who are in close contact or share food. You can also get the virus by touching a surface that's been contaminated with norovirus, which is a type of virus.
Rotavirus.This is the most common cause of viral gastroenteritis in children. When they put their fingers or other objects contaminated with the virus into their mouths, it can also spread through contaminated food. Infants and young children are particularly at risk for this type of infection.
People who are infected with rotavirus may not have any symptoms, but they can still spread the illness. This is a problem in places like nursing homes, where adults with the virus can unknowingly pass the virus to other people. A vaccine is available that can prevent viral gastroenteritis. The vaccine appears to be effective in preventing the infection in countries including the United States.
You can get sick from eating some shellfish, such as raw oysters or diarrheal viruses that are passed when someone with a virus handles food you eat. Contaminated water is one cause of this illness, but it is often the result of someone with a viral infection handling food without washing their hands afterwards.
Risk factors
Gastroenteritis can affect people of all ages, anywhere in the world.
People who are more likely to get gastroenteritis include:
- Young children.Children in child care centers or elementary schools are especially vulnerable because their immune systems are not fully developed.
- Older adults.Older adults' immune systems are less efficient than those of adults in their twenties or thirties. Older people in nursing homes are more vulnerable to infections because their immune systems have weakened. They also live in close contact with others, who may pass along germs.
- Schoolchildren or dormitory residents.When people are in close quarters together, it is possible for an intestinal infection to spread.
- Anyone with a weakened immune system.If you have a low resistance to infection, for example if your immune system is weakened by HIV/AIDS chemotherapy or another medical condition, you may be more susceptible to infection.
Each type of gastrointestinal virus has a season when it's most active. For instance, you're more likely to contract rotavirus or norovirus in the winter and spring in the Northern Hemisphere.
Complications
The main complication of viral gastroenteritis is dehydration. If you're healthy and drink enough fluids to replace what you lose from vomiting and diarrhea, dehydration shouldn't be a problem.
If an infant, an older adult, or someone with a weakened immune system loses more fluids than they are able to replace, they may become dehydrated. This could lead to hospitalization in order for lost fluids to be replaced through an IV injection in the arm. Dehydration rarely results in death.
Prevention
To prevent the spread of intestinal infections, follow these precautions:
- Get your child vaccinated.A vaccine against rotavirus gastroenteritis is available in some countries. Given to children in the first year of life, it seems to be effective in preventing severe symptoms of this illness.
Wash your hands thoroughly.Make sure your children do too. If your children are older, teach them to wash their hands especially after using the toilet.
After changing diapers, wash your hands thoroughly with warm water and soap. Rub your hands well for at least 20 seconds. Wash around the fingernails and creases of the hands. Then rinse thoroughly. Carry sanitizing wipes and hand sanitizer in case you get sick. There are times when soap and water aren't available, so it is useful to have a sanitizer on hand.
- Protect your personal belongings by using different items around your home.Do not share eating utensils, drinking glasses, and plates. Use separate napkins when using the bathroom.
- Prepare food safely.Before eating any fruits or vegetables, wash your hands and kitchen surfaces. Avoid preparing food if you are feeling sick.
- Keep your distance.If you are sick with the flu, stay away from other people.
- Disinfect hard surfaces.If someone in your home has viral gastroenteritis, disinfect hard surfaces by using a mixture of 5-25 tablespoons (73 to 369 milliliters) of household bleach to 1 gallon (3.8 liters) of water.
- Don't touch laundry that may have been exposed to a virus.If someone in your home has viral gastroenteritis, wear gloves while handling laundry. Washing clothes and bedding in hot water and drying them on the hottest setting is also recommended.After touching laundry, it's important to wash your hands well.
- Check out your child care center.Make sure there is a separate room for changing diapers and preparing or serving food. The room should have a sink as well as a place to dispose of diapers.
Take precautions when traveling
When traveling to other countries, you may be at risk of getting sick from contaminated food or water. To reduce your risk, follow these tips:
- Stay hydrated by drinking only well-sealed bottled or carbonated water.
- Do not drink ice cubes that have come from polluted water.
- Use bottled water to brush your teeth.
- Avoid foods that have been touched by humans, including peeled fruits, raw vegetables, and salads.
- Avoid undercooked meat and fish.
Diagnosis
Your doctor will probably diagnose stomach flu based on your symptoms and often by checking if you have similar symptoms in other people. A rapid stool test can detect rotavirus or norovirus, but there are no quick tests for other viruses that cause the stomach flu. Your doctor may ask you to submit a stool sample in order to rule out a possible bacterial or parasitic infection.
Treatment
There is no specific medical treatment for viral gastroenteritis. Antibiotics are not effective against viruses. First, self-care measures such as drinking plenty of water are necessary.
Clinical trials
Check out studies at the Mayo Clinic that are testing new treatments and tests to help prevent, treat, or manage this condition.
Lifestyle and home remedies
To help you feel more comfortable and prevent dehydration, try the following:
- Let your stomach settle. Stop eating solid foods for a few hours.
- Drink fluids often, such as icy chips or sips of water.You might try drinking clear soda, clear broths, or noncaffeinated sports drinks. Sometimes you can try oral rehydration solutions. Drink plenty of fluids every day in small amounts.
- Ease back into eating.While you are recovering, you can gradually resume eating your normal diet. You might start by eating bland, easy-to-digest foods such as crackers, soup, oatmeal, noodles, bananas, and rice. If nausea returns, stop eating.
- Wait until you feel better before eating or drinking anything.Foods that include caffeine, alcohol, nicotine, and highly seasoned foods can all make you feel tired.
- Get plenty of rest.The illness and dehydration may have made you feel weak and tired.
- Try anti-diarrhea medications.Some adults may find it helpful to take loperamide (Imodium) or bismuth subsalicylate (Pepto-Bismol) to manage their symptoms. However, if you have bloody diarrhea or a fever, it may be something else.
For infants and children
When your child has an intestinal infection, the most important goal is to replace fluids and salts that were lost. These suggestions may help:
Help your child rehydrate.Oral rehydration solution is available at pharmacies without a prescription. Talk to your doctor if you have any questions about how to use it.
Don't give your child plain water - it won't be absorbed well and won't replenish lost electrolytes. Avoid giving your child apple juice for rehydration - it could make diarrhea worse.
- Rehydrate your child by getting them back on a normal diet once they are hydrated.After your child has been rehydrated, reintroduce them to their regular diet. This might include toast, yogurt, and fruits and vegetables.
- Avoid certain foods.Do not give your child sugary foods such as ice cream sodas and candy. These can cause diarrhea to worsen.
- Take care to ensure that your child gets enough rest.Your child may have been sick and dehydrated because of it.
- Do not give your child store-bought anti-diarrheal medications, as they may not be effective. Instead, get them water and laxatives to drink if they have diarrhea.Do not take your child's antiviral medication unless your doctor tells you to. This may make it more difficult for the body to fight the virus.
If your infant is sick, let their stomach rest for 15-20 minutes after vomiting or having diarrhea. If you are breastfeeding, your baby should nurse. If the infant is bottle-fed, offer them a small amount of a rehydration solution or regular formula. Don't change the formula that your baby is already prepared with.
Preparing for your appointment
Most people see their doctor first if they need to see a doctor. If there are any questions about the diagnosis, your doctor may refer you to an infectious disease specialist.
What you can do
Making a list of questions will help you get the most out of your visit to the doctor. Some questions you might want to ask your doctor include:
- What are the possible causes of the symptoms? Are there any other causes that could be responsible?
- Is there a need for tests?
- What are the best ways to treat this condition? Are there any other options?
- Is there a need to take medicine?
- What can I do at home to improve my symptoms?
What to expect from your doctor
The doctor may ask you some questions, such as:
- When did symptoms begin?
- Has the problem been ongoing or does it come and go?
- What are the symptoms like?
- What do you think might help improve symptoms?
- What if anything seems to make the symptoms worse?
- Do you know of anyone else who has been experiencing the same symptoms?
What you can do in the meantime
Drink plenty of fluids. You can gradually resume eating regular foods as long as your child is recovering. If your child is sick, follow the same approach: offer plenty of fluids. When possible, start having them eat their regular diet. You should continue to feed your child as usual while breastfeeding or using formula. If giving your child an oral rehydration solution available over the counter at pharmacies would help, speak to your child's doctor.