Stomach virus vs. flu: What is the difference?

Stomach flu is an infection in the intestines and stomach. Doctors refer to it as viral gastroenteritis. It can cause diarrhea, abdominal cramping, and nausea or vomiting.

Although some people may refer to viral gastroenteritis as stomach flu, the viruses that cause influenza are different from those causing gastroenteritis.

People may develop stomach flu symptoms rapidly, but they typically last less than a week.

Influenza is a respiratory viral infection that some people refer to as flu. Influenza viruses cause infection, which occurs in the nose, throat, and sometimes the lungs. People may experience symptoms that include fever or chills, a cough, sore throat, and body aches.

The following table gives an overview of both conditions:

The symptoms of stomach flu include:

• watery diarrhea
• abdominal pain or cramping
• nausea
• vomiting
• fever

Some people may consume too few fluids during stomach flu, which can lead to dehydration.

The symptoms of flu include:

• fever and chills
• cough
• sore throat
• runny or blocked nose
• body aches
• headaches
• fatigue

Vomiting and diarrhea can occur in both stomach flu and influenza. However, with influenza, these symptoms are more common in children rather than adults.

Norovirus is the most common cause of stomach flu, but other viruses that can cause stomach flu include:

• rotavirus
• adenovirus
• astrovirus

Certain bacteria can also cause stomach flu from contaminated foods and drink. Stomach flu germs can pass between people through contact with infected stools or vomit.

Influenza viruses cause flu. Doctors divide influenza viruses into either A, B, C, or D. Influenza A and B viruses are the most common cause of flu in humans and can lead to flu outbreaks.

Flu viruses can pass between people through tiny, infected droplets. These droplets can spread when people with the virus sneeze, cough, or talk.

People do not always need treatment for stomach flu or influenza, but home care can relieve the symptoms.

Stomach flu

People may recover from stomach flu on their own without any medical treatment. Home remedies to ease the symptoms include replacing lost fluids and electrolytes with:

• water
• fruit juice
• sports drinks
• broth
• saltine crackers

Children, older adults, and those with a weakened immune system or severe diarrhea will require oral rehydration solutions. Some people will also require diarrhea treatments, such as Imodium.

People who have blood in their stools or fever may have a bacterial infection or parasites that require treatments from a doctor, such as antibiotics.

Influenza

Most people with flu will have mild symptoms that require no medical treatment. Steps to help people recover from flu include:

• staying at home and resting
• drinking plenty of water to replace lost fluids and prevent dehydration
• avoiding close contact with others
• washing hands regularly with soap and water

In more severe cases, a doctor might prescribe antiviral medications.

The Centers for Disease Control and Prevention (CDC) recommend that anyone at high risk of complications takes antiviral treatment within 2 days of flu symptoms first appearing.

Getting the yearly flu vaccine is also an important measure to prevent flu and its complications.

People with stomach flu should contact their doctor straight away if they have the following symptoms:

• diarrhea that lasts longer than 2 days
• a change in mental state, such as severe fatigue or irritability
• a high fever
• frequent vomiting
• 6 or more loose stools in a day
• severe pain in the rectum or abdomen
• black or tarry stools
• blood or pus in stools
• signs of dehydration

People with influenza should contact a doctor for the following symptoms:

• difficulty breathing
• shortness of breath
• persistent chest or abdominal pain
• dizziness, confusion, or difficulty waking
• seizures
• severe muscle pain or weakness
• worsening cough or fever

Stomach flu is an infection of the stomach and intestines. Viruses, such as norovirus, are usually the cause of stomach flu. Symptoms of stomach flu include vomiting, nausea, and diarrhea.

Influenza is a respiratory infection. It is the result of influenza viruses, which cause symptoms that include a sore throat, runny nose, and sometimes a fever.

Both conditions require resting at home and drinking plenty of fluids. In severe cases, medical treatment is necessary and may include antiviral medications or antibiotics.