Gastroenteritis: Symptoms and Signs

January 5, 2024

Gastroenteritis: Symptoms and Signs
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Gastroenteritis is a very common illness affecting people of all ages.Young children are especially susceptible to it.Vomiting and diarrhea are symptoms of gastroenteritis, commonly known as “stomach flu”, which is inflammation of the stomach and intestinal lining. Usually a parasite , bacteria or virus may be the cause.

What is Gastroenteritis ?

An infection or inflammation of the digestive system can cause gastroenteritis. Symptoms such as vomiting, diarrhea, and cramping in the abdomen are common. The illness often gets better on its own in a matter of days. Gastroenteritis can be caused by a number of things, including bacteria, viruses, bacterial toxins, parasites, specific chemicals, and some medications. Gastroenteritis is highly transmissible.

Types of Gastroenteritis

  • Viral gastroenteritis – The most prevalent kind of gastroenteritis is caused by viral infections. In 60% of cases, viruses are the cause of gastroenteritis. Fifty percent of cases of viral gastroenteritis are caused by norovirus alone.
  •  The term “stomach flu” is occasionally used to refer to viral gastroenteritis, but it is not a recognized medical term. Viral gastroenteritis is not caused by influenza (flu) viruses. 
  • Bacterial gastroenteritis – Bacterial gastroenteritis is brought on by bacterial infections. 
  • Fungal gastroenteritis – Fungal gastroenteritis can be brought on by fungal infections.
  • Chemical gastroenteritis – The lining of your stomach and intestines can become damaged and inflamed by chemicals. Even in tiny quantities, certain chemicals have this effect. Others, such as alcohol and some drugs, can result in gastroenteritis when taken in higher concentrations.

 Gastroenteritis Symptoms 

An attack on your intestines by gastroenteritis results in initial signs and symptoms like:

  • appetite loss
  • diarrhea, vomiting fits, and nausea.
  • abdominal pain and cramps.


  • diarrhea, bloody stools (poo), pus in the stools
  • general illness, including fatigue and body aches.

Gastroenteritis Stages

The symptoms of gastroenteritis often appear suddenly and without warning to a lot of people. On the first day, you may have frequent episodes of diarrhea or vomiting. One to two days after being exposed to the virus, symptoms start to appear. Thankfully, they typically pass in one or two days, ending the issue just as quickly.

The stages of  gastroenteritis infection are:

  • The likelihood of contracting the stomach flu from a member of your community is higher in enclosed spaces such as schools, nursing homes etc. 
  • The virus will start to replicate inside your body as soon as it enters you. This is the incubation phase. Until the virus replicates sufficiently to notify your immune system, you won’t experience any symptoms. Depending on the virus, this typically takes a few days.
  • As an acute infection, viral gastroenteritis is sudden and transient in nature. Your immune system initiates an inflammatory response to eradicate the virus as soon as it detects a threat. This is the cause of disease symptoms. Once it is successful, the symptoms will go away.
  • When your immune system defeats the virus, you’ll notice a decrease in your symptoms. Your symptoms will eventually go away, and you’ll get better. However, you might still be contagious for a few days if the virus is still present in your feces.

Causes of Gastroenteritis

Gastroenteritis can be brought on by a variety of viruses that infect the gastrointestinal tract.Among the most prevalent are:

  • Norovirus – This is the most common cause of adult gastroenteritis, estimated to be responsible for 50% of cases globally. It is more resilient to disinfectants and temperature than others.

  • Rotavirus – The most common cause of gastroenteritis in children worldwide is rotavirus. Most adults are immune because most get it before the age of three. A vaccine is now available.

  • Astrovirus – Astroviruses primarily impact children under three years old. They frequently spread through childcare facilities. However, elder care facilities can also be a conduit for them.
  • Adenovirus – Though they can also cause gastrointestinal infections if inadvertently consumed, adenoviruses are more commonly associated with respiratory infections. All ages are afflicted.

Some other causes of gastroenteritis can be:

  • Bacteria, such as the Campylobacter bacterium
  • Bacterial toxins: although bacteria do not directly cause disease, their toxic byproducts can contaminate food. Certain staphylococcal bacterial strains generate toxins that have the potential to cause gastroenteritis.
  • Medication: Certain medications, like antibiotics, can cause gastroenteritis in susceptible individuals
  • Chemicals: Lead poisoning, for example, can cause gastroenteritis.
  • Certain shellfish can also cause illness, particularly raw or undercooked oysters. Viral diarrhea is caused by tainted water sources. 

Complications of Gastroenteritis

The main adverse effect of viral gastroenteritis is dehydration, which is defined as a considerable loss of water as well as essential salts and minerals.Dehydration shouldn’t be an issue if you’re in good health and drink enough to make up for the fluids you lose through diarrhea and vomiting.

When people lose more fluids than they can replace, severe dehydration can happen to newborns, the elderly, and people with weakened immune systems. It may be necessary for them to stay in a hospital so that an IV can replace any lost fluids in their arms. Rarely can dehydration result in death.

Long-term gastroenteritis may cause damage to your intestines and stomach. For instance, you may get bleeding ulcers in your organs. Few varieties of gastroenteritis have a longer duration.

When to call a doctor?

There are certain indicators to look out for in case of gastroenteritis symptoms. If any of these apply to you or your child, it’s critical that you get in touch with a doctor straight away.

Adults may experience the following: 

  • A shift in mental health, such as irritability or fatigue
  • Prolonged diarrhea exceeding two days
  • High fever
  • Frequent vomiting
  • More than six loose stools in one day
  • Intense abdominal or rectum pain
  • Black, tarry, or bloody stools
  • Symptoms of dehydration, including headache, dry mouth, thirst, dark urine, and less frequent urination than usual

For young children and infants, these consist of:

  • A shift in the child’s mental state, characterized by irritability or lethargy
  • Diarrhea that lasts longer than one day
  • High fever in older children
  • Any fever in infants
  • Frequent loose stools
  • Frequent vomiting
  • Severe abdominal or rectum pain
  • Dehydration signs and symptoms, such as dry mouth, thirst, reduced urination, lack of wet diapers for three hours or longer, and lack of tears when crying
  • Black, tarry, or bloody or pus-filled stool

Gastroenteritis and Children

Since kids can become dehydrated easily, it’s critical to watch out for symptoms of severe thirst, dry lips, and/or skin if your child is sick with the stomach flu.Children suffering from gastroenteritis should not attend daycare or school until all symptoms have subsided. Before giving your child any medication, consult your physician. Children under the age of five should typically not be given medications intended to treat vomiting and diarrhea.

Risk Factors for Gastroenteritis

Gastroenteritis affects almost everyone. However, the risk factors are higher if you:

  • Are either older than 65 or younger than 6.
  • Work or reside in an assisted living facility.
  • Consume raw meat or fish.
  • Take a trip overseas, particularly to less developed areas.
  • Suffer from a long-term illness that impairs immunity.
  • Regularly use specific drugs or alcohol


In most cases, symptoms resolve within a few days. If you see no improvement, get in touch with a doctor. Individuals with weakened immune systems might require medication to lessen symptoms or treatment for dehydration. If you’re not getting better, it’s also possible that you have a different illness.

Frequently Asked Questions

1. How does viral gastroenteritis spread?

Viral gastroenteritis is contagious and spreads from person to person through contact with vomit or feces from an infected individual.Small amounts of feces or vomit can carry the virus, especially if you don’t properly wash your hands after using the restroom and touch items or surfaces that other people have used,make meals and beverages and serve them to others,give a handshake or make contact with someone else.

Even those without symptoms who are infected can still spread viruses.

2. What are the first signs of gastroenteritis?

Symptoms of gastroenteritis frequently appear suddenly. Initially, there are gastrointestinal symptoms. You may experience nausea, vomiting, cramps or diarrhea on multiple occasions in a short amount of time.

3. What is the duration of gastroenteritis?

Most gastroenteritis types are transient, usually lasting one or two days. Most bacterial and viral infections are mostly treatable by your body on their own. Certain kinds might require medical attention to go away or endure longer.

4. How long is gastroenteritis contagious?

The two days following an infection and while you are experiencing symptoms are when gastroenteritis is most contagious. It is during these last two days that your body is excreting the infection through your stools.

Disclaimer: We recommend consulting a Doctor before taking any action based on the above shared information.


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