Viral gastroenteritis - including symptoms, treatment and prevention

Gastroenteritis (gastro) is an infection of the stomach and intestines (bowel).

Many types of germs can cause gastro, but a virus is the most common. Examples of viruses that cause gastro are rotavirus and norovirus.

In most cases, viral gastro starts with vomiting and then leads to diarrhoea (runny, watery poo).

How viral gastroenteritis is spread

Viral gastroenteritis can be highly infectious so it can spread very easily.

This can happen when people:

  • Breathe in tiny droplets from someone who is vomiting.
  • Touch surfaces that have germs on them and then touch their mouth.
  • Eat food or drink water that has been contaminated.

Germs can get onto surfaces and food when:

  • Someone vomits and tiny droplets land on nearby surfaces.
  • An infected person doesn't wash their hands properly after going to the toilet and then touches food or objects.
  • Someone doesn't wash their hands properly after changing a sick baby's nappy and then touches food or surfaces. 

Signs and symptoms of viral gastroenteritis

Symptoms usually last 1 or 2 days and include:

  • mild fever
  • nausea and vomiting
  • stomach cramps
  • diarrhoea
  • feeling unwell

Diagnosis of viral gastroenteritis

Diagnosis is based on the history and clinical examination.

Laboratory testing of a sample of poo can sometimes identify the virus. 

Incubation period

(time between becoming infected and developing symptoms)

24 to 72 hours.

Infectious period

(time during which an infected person can infect others)

During illness and for at least 24 hours after symptoms have disappeared.

Treatment for viral gastroenteritis

There is no specific treatment for useful viral gastroenteritis. Most gastroenteritis infections resolve without treatment. 

The following are general recommendations for the treatment of gastroenteritis:

  • Give plenty of fluids. Oral rehydration solution is highly recommended for children with mild to moderate dehydration. It is available at pharmacies and should be given following the instructions on the packaging.
  • Mildly unwell children should be given their usual fluids more often.
  • Carbonated (fizzy) drinks or undiluted juice should be avoided.
  • Medicines to prevent vomiting or diarrhoea should not be given (especially in children), except where specifically advised by a doctor. 
  • Breastfed babies should continue to be breastfed throughout their illness.
  • For more detailed information about managing your child at home, see the Royal Children's Hospital gastroenteritis fact sheet.
  • Some people may need intravenous (into the vein) fluids if they are very dehydrated.

When to seek medical advice

Seek medical advice if there are any of the following symptoms:

  • stomach pain that is getting worse.
  • frequent vomiting or diarrhoea or both.
  • blood or mucous in your poo with a fever.
  • passed little or no urine, or your urine is dark and smelly.
  • signs of dehydration, such as thirst and decreased urination, lethargy, dry mouth, feeling faint on standing. 

Babies under six months old are at higher risk of dehydration, so you should take them to see a doctor or health professional if they show signs of gastro.

Prevention of viral gastroenteritis

  • Exclude people with viral gastroenteritis from childcare, preschool, school and work until there has been no diarrhoea or vomiting for at least 24 hours. If the gastroenteritis is known or suspected to be caused by norovirus, the exclusion period is 48 hours.
  • During outbreaks in childcare, exclude staff and children for 48 hours.
  • If working as a food handler in a food business, the exclusion period should be until there has been no diarrhoea or vomiting for 48 hours.
  • Infants, children and adults with viral gastroenteritis should not swim until there has been no diarrhoea for 24 hours.
  • Follow good hand washing and keeping areas clean procedures.

Useful links

National

SA Health