What is the issue?
Analysis by the Victorian Infectious Diseases Reference Laboratory has identified a new strain of norovirus which may lead to increased gastroenteritis outbreaks. Previously, the emergence of new strains of norovirus has led to an increase in the number of cases and outbreaks due to a lack of immunity to the specific strain.
Norovirus is the most common cause of viral gastroenteritis. It affects people of all ages however certain groups are at higher risk, particularly those in aged care facilities or child care centres. Norovirus is known to cause at least 65 per cent of gastroenteritis outbreaks affecting settings like these in Victoria.
As is common with many viruses, norovirus can mutate (change) and, through routine surveillance from our public health laboratories, we know it does so frequently. Occasionally the virus changes to become so different that the community has no effective immunity. This means that everyone who comes into contact with it is very susceptible to illness; whether contact is with faeces of an infected person or by being close to an infected person who is vomiting.
In order to ensure effective control measures are instigated and maintained, it is important to ensure all suspected cases of norovirus have stool samples sent for norovirus testing, and not just culture and antimicrobial sensitivity testing.
Who is at risk?
High risk populations include:
- Older adults (> 65 years)
- Young children (< 5 years)
- People with compromised immune systems.
It is important to remember that older people living in residential aged care services are more prone to gastroenteritis and because of underlying medical conditions, can often become unwell quickly. They require close monitoring and supervision of their care needs. Medical attention should always be sought for residents with symptoms of gastroenteritis particularly if their symptoms worsen.
Symptoms and transmission
Transmission of norovirus is via the faecal-oral route. It can spread through direct person-to-person contact, indirectly through ingestion of contaminated food or water or touching contaminated environmental surfaces or objects. The incubation period is usually 10 – 50 hours.
Norovirus is characterised by an acute onset of nausea, vomiting and diarrhoea. Other symptoms may include low-grade fever, headaches and myalgia. Symptoms usually resolve within 24 to 72 hours.
Prevention / treatment
Effective hand washing is the most important measure in preventing the spread of infection.
To help prevent the spread of norovirus, facility managers should remind staff to:
- Avoid attending work when experiencing gastroenteritis symptoms until 48 hours after symptoms completely resolve, and to advise management of their illness.
- Maintain strict hand hygiene procedures at all times. Hands must be washed with soap and water, after going to the toilet and before eating or preparing food, or when visibly soiled.
- Use appropriate personal protective equipment, such as aprons and gloves, when toileting patients or attending patients with gastroenteritis symptoms.
To help prevent the spread of norovirus, everyone, including patients and people in the community, should:
- Thoroughly wash their hands with soap and water after going to the toilet and before eating or preparing food;
- Avoid preparing food for others until 48 hours after gastroenteritis symptoms have completely resolved;
- Stay away from sensitive settings such as hospitals, residential care facilities and childcare settings until they have been free of the symptoms of gastroenteritis for 48 hours.
Under the Public Health and Wellbeing Regulations (2009), two or more related gastroenteritis cases is required to be notified to the Department of Health and Human Services by medical practitioners or affected facilities within five days of initial diagnosis. Notifications can be made online at http://ideas.health.vic.gov.au via telephone on 1300 651 160 or faxed on 1300 651 170.
Guidelines for the investigation of Gastroenteritis
Training resources on the use of personal protective equipment to prevent
Gastroenteritis Kit for residential aged
Better Health Channel factsheet:
Communicable Disease Prevention and Control Section, phone 1300 651 160 or email firstname.lastname@example.org.