Although many different types of viruses cause gastroenteritis, norovirus is one of the most common.
It tends to develop as an outbreak where many people are affected at the same time.
This occurs where large crowds of people are gathered in closed environments – usually schools, restaurants, aged care homes and cruise ships.
Norovirus organisms are found in the vomit or faeces of infected people. The virus is very contagious and can easily spread by eating or sharing contaminated foods, touching contaminated surfaces or coming into contact with an infected person (including vomit and faeces).
Symptoms usually develop from between 12-48 hours after ingesting the virus. The most common symptoms of gastroenteritis are abdominal pain, diarrhoea, nausea and vomiting.
Other symptoms can include fevers, chills, muscle aches and lethargy. Children also tend to have more severe and prolonged vomiting than adults.
Most symptoms resolved within 1-2 days with no long-term issues for healthy people, however young children, elderly people and those who are immunocompromised may have longer lasting episodes. Severe infections may also need treatment in hospital.
Diagnosis can usually be made from clinical assessment of the symptoms, although a formal diagnosis can be made by taking a faecal sample for lab testing. Most public health authorities will usually need this information to help in controlling disease outbreaks.
Although no cure exists for norovirus infections, mild symptoms can be treated at home with plenty of rest and drinking plenty of fluids to keep well hydrated.
Dehydration is the main complication from norovirus infections and can cause significant complications if not corrected.
Some pharmacies also sell oral rehydration solutions that can help replace vitamins and minerals lost from vomiting or diarrhoea. Drinks that are high in sugar (soft drinks and cordial) can make diarrhoea worse and these should be diluted with water.
More severe cases where people cannot keep any fluids down due to vomiting will need hospital treatment, usually with intravenous fluids and medication to control vomiting.
People can still be infectious for up to 48 hours when all the symptoms have resolved. People that are still infectious should not handle food or be closely caring for young children or the elderly during this period of recovery.
Norovirus also comes in many different strains which makes it difficult for the body to develop life-long immunity to the virus, meaning people can have repeated infections throughout their life.
No current vaccines are available for the virus and antibiotics will not treat norovirus infections. However, there are many strategies to help reduce the risk of catching norovirus. Most importantly, frequent hand washing with soap and water will reduce the spread of the virus (especially after using the toilet and before eating or preparing food).
Washing clothes of infected people and cleaning contaminated surfaces with disinfectant or diluted bleach will also minimise spread. Children or adults who are ill should not go to childcare, school or work for at least 48 hours after the vomiting and diarrhoea stops.
For more information, see your doctor if you have concerns regarding norovirus or if you have symptoms of vomiting or diarrhoea.
More information can also be found on Health Direct and the Department of Health fact sheet.
