Guidelines for the public health management of gastroenteritis outbreaks due to norovirus or suspected viral agents in Australia
This information is for staff in institutions or Public Health Units to distribute to the public.
What is norovirus gastroenteritis?Norovirus gastroenteritis is diarrhoea and vomiting caused by a virus in the digestive system. There are many viruses that can cause gastroenteritis but norovirus is one of the most common. It often occurs as outbreaks where many people get sick at the same time. Common names used for gastroenteritis due to norovirus are ‘gastric flu’ or ‘stomach flu’, ‘winter vomiting’ and ‘viral gastro’.
What are the symptoms?Common symptoms of viral gastroenteritis include nausea, diarrhoea, vomiting and abdominal cramps. Other symptoms may include headache, chills, low grade fever, muscle aches and tiredness. The illness often begins suddenly and symptoms last between 24–48 hours.
How are noroviruses spread?Noroviruses are usually spread from one infected person to another. Noroviruses are often associated with outbreaks where people are in close living spaces, such as Aged-care facilities, hospitals, cruise ships and community sporting events. There are different ways in which people become infected:
- eating food or drink that is contaminated with norovirus. This can occur in two ways:
- when the food may become contaminated during growing or processing, especially oysters
- when a person who is ill prepares food for other people.
- touching surfaces or objects contaminated with norovirus and then putting their hands in their mouth
- having direct contact with another person who is infected (for example, caring for someone who is ill)
- small particles of vomit settle on people or food in the same room and result in infection.
When do symptoms begin?Symptoms of vomiting, nausea and diarrhoea usually begin 24–48 hours after ingestion of the virus, but they can appear as early as 12 hours after someone is exposed to the virus.
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Are noroviruses contagious?Yes, noroviruses are highly contagious. People infected with norovirus can spread the virus from the day they start to feel ill to at least 2 days after diarrhoea or vomiting stops.
Who gets norovirus?Anyone can become infected with norovirus. There are many different strains of norovirus which makes it difficult for a person’s body to develop long-lasting immunity. Therefore, you can get norovirus more than once during your lifetime.
Is there any treatment available?No specific medication or antibiotics exists for norovirus infection and there is no vaccine available.
When people are ill with diarrhoea or vomiting they should drink plenty of fluids to prevent dehydration. People with severe symptoms or dehydration should seek medical advice.
How can norovirus infections be prevented?There are some simple measures to prevent infection:
- Wash hands with soap and water after using the bathroom and changing nappies.
- Wash hands with soap and water before eating, or preparing food for oneself or others.
- Do not prepare food for others while you have gastroenteritis, or for at least 2 days after diarrhoea or vomiting stops.
- Immediately remove and wash clothing or bedding that may be contaminated with diarrhoea or vomit.
- After an episode of vomiting or diarrhoea, clean the area with detergent and warm water and then disinfect contaminated surfaces with household bleach diluted to 1000 parts per million (ppm). (Note: Bleach may damage soft furnishings.)
- People who are ill with norovirus or suspected viral gastroenteritis should be excluded from child care, school or work for a minimum of 48 hours after diarrhoea or vomiting stops.