Viral gastroenteritis

Viral gastroenteritis (often called 'viral gastro’ or ‘stomach flu’) is a common viral infection of the stomach and bowel that results in vomiting and diarrhoea. It is usually a mild illness and can be caused by a number of different viruses such as norovirus and rotavirus.

Symptoms

The two main symptoms of viral gastroenteritis are diarrhoea and/or vomiting.

Other symptoms may include:

• nausea
• stomach cramps and pain
• muscle aches
• tiredness
• headaches
• mild fever.

Symptoms take between 1 to 3 days to develop, with illness usually lasting 1 to 2 days.

How viral gastroenteritis is spread

Viral gastroenteritis is highly infectious and can easily spread between people.

You become ill by accidentally taking in the virus through your mouth, which happens when your hands have small amounts of faeces (stools, poo) or vomit from an unwell person.

This can occur through:

• close contact with another person, for example shaking hands with someone who has been sick and has the virus on their hands
• direct contact with the vomit or faeces of an infected person
• contact with contaminated objects or surfaces (such as door and tap handles), for example surfaces touched by a person who has been sick and left virus from their hands on those objects
• eating or drinking contaminated food or drink

Infection can also be spread in the air when people vomit.

Who is at risk of infection

Viral gastroenteritis can affect people of all ages and backgrounds.

Most people who have viral gastroenteritis make a full recovery without any long-term problems.

Viral gastroenteritis can be a serious illness for people who are unable to drink enough fluids to replace what they have lost. This can include infants, young children, the elderly and people with certain disabilities. Those who have weakened immune systems are also at risk of severe illness because of their reduced ability to fight off the infection.

Diagnosis

Viral gastroenteritis is usually diagnosed based on a person’s symptoms without any testing. However, if there are a high number of cases in one place, testing might be important to identify what is causing the illness to guide public health responses. This involves testing samples of faeces.

Treatment

There is no specific treatment for viral gastroenteritis. It is very important to rest and drink lots of fluids (such as plain water or oral rehydration solutions) to avoid dehydration.

If your child has viral gastroenteritis

Children can become dehydrated quickly. The main treatment is to replace the fluids your child loses from diarrhoea and/or vomiting. Do this by encouraging your child to drink fluids often. The best types of fluid to prevent dehydration are water, oral rehydration solution (such as Gastrolyte, HYDRAlyte, Pedialyte or Repalyte), breastmilk or an infant’s usual milk formula.

Different approaches can be used to replace fluids in children depending on their age and if they are breastfed.

For more detailed information about managing your child at home, see the Royal Children’s Hospital gastroenteritis fact sheet.

If your child’s symptoms do not seem to be improving over time, your child should be seen by a doctor.

Prevention

The most effective way of preventing viral gastroenteritis is to practice good hand washing.

This is achieved by washing hands thoroughly using soap and running water for at least 20 to 30 seconds, followed by drying hands with a clean towel.

You should always wash your hands before:

• before preparing food and before eating
• after using the toilet
• after changing nappies
• after helping someone who has diarrhoea or vomiting.

Preventing spread of infections

While you have gastroenteritis symptoms, and for the 48 hours (2 days) after your symptoms resolved, it is important to keep your hands clean by washing them with soap and water for at least 20 to 30 seconds, often and thoroughly. Alcohol hand sanitiser is generally less effective than soap and water but can be used if these are not available.

You should also avoid preparing food for people during this time.

Immediately remove and wash any clothes or bedding contaminated with vomit or diarrhoea using detergent and hot water. If using cold water only, also add a laundry sanitiser to the wash.

Clean contaminated surfaces (for example benches, floors and toilets) immediately using detergent and hot water. Then disinfect surfaces using a bleach-based product diluted according to the manufacturer’s instructions. Children’s toys should be cleaned with detergent and then disinfected, rinsed and dried before sharing toys with other children.

Rotavirus vaccination

Rotavirus vaccination is available on the National Immunisation plan and is given to infants at 2 and 4 months. The interval between doses is at least four weeks.

Vaccinating your child against rotavirus helps to protect them from becoming severely unwell if they have rotavirus.

Find out more about rotavirus immunisation at the ACT Health immunisation schedule.

Staying home from school or work

Anyone with vomiting or diarrhoea should rest at home and not attend work, school or childcare, or visit a hospital or residential care facility, until vomiting and diarrhoea have stopped for 48 hours (2 days).

Outbreaks

Outbreaks of viral gastroenteritis are common in childcare centres and aged care facilities, and can also occur in healthcare settings (including hospitals) and schools. An outbreak is classified when there are two or more related cases that have vomiting and/or diarrhoea within 24 hours. Under the Public Health Act 1997, outbreaks in residential care, childcare and health care settings should be notified to the Health Protection Service.

During outbreaks in childcare, it is recommended that staff and children with vomiting and/or diarrhoea stay away from the centre until at least 48 hours after their symptoms have stopped.

During outbreaks in aged care, it is recommended that residents with vomiting and/or diarrhoea be isolated until at least 48 hours after their symptoms have stopped. Anyone entering their room should be following appropriate infection prevention and control measures. Staff with symptoms must stay away from the facility until at least 48 hours after their symptoms have stopped.

In all settings (including childcare and aged care facilities), specific outbreak control measures should be in place. Public Health Officers from the Health Protection Service will liaise closely with facilities to provide appropriate advice and guidance on infection control measures during outbreaks.

More information

For more information on viral gastroenteritis contact your doctor or call the Health Protection Service, Communicable Disease Control Information Line during business hours on (02) 5124 9213.

Acknowledgements

• Heymann DL, 2015, Control of Communicable Diseases Manual, 20th edition.
• Royal Children’s Hospital Melbourne, Gastroenteritis fact sheet, 2018.