1.0 Introduction
These guidelines provide information on best practice to enable staff to recognise and take appropriate action when a patient(s) is suspected to have viral gastroenteritis. Prompt and effective measures are essential in controlling the spread of infection between anyone within the healthcare setting (patients, visitors, and staff).
Viral gastroenteritis spreads easily in healthcare settings and can be difficult to control. Viruses like norovirus (a small round structured virus, the most common cause of gastroenteritis outbreaks in hospital and the community),and human rotavirus, are easily introduced by infected patients, staff or visitors. These viruses can survive in the environment for many days and can affect more than half of the people that are exposed to them.
Please refer to the National Infection Prevention and Control Manual (NIPCM) for England (NHSE 2024) A to Z of Pathogens resource
for links to national guidance for specific infectious causes of diarrhoea (including viral, bacterial, and protozoal agents).
1.1 Norovirus
Norovirus is the most common cause of viral gastroenteritis in the UK (Phillips et al 2010) and was first identified in 1972 from diarrhoea stool specimens sent from cases and family contacts of an elementary school outbreak of gastroenteritis in Norwalk, Ohio in 1968. The virus belongs to the Caliciviridae family of small, round, single-stranded RNA viruses, and Genotype GII.4 is responsible for the majority of cases and outbreaks in the UK.
Norovirus can cause illness in people of all ages, and infection can occur all year round, although there are clear seasonal (winter) peaks in the UK.
Person to person is the most common mode of transmission, but norovirus has also been associated with foodborne outbreaks caused by infected food handlers, contaminated shellfish and other produce.
1.2 Rotavirus
Rotavirus is the leading cause of viral gastroenteritis in infants and children worldwide, causing severe dehydrating illness (NCCWCH 2009). From July 2013, an oral vaccine has been available in the UK (two doses for babies aged 2 months and 3 months), alongside other routine childhood vaccines. The vaccine protects against approximately 90% of rotavirus strains in circulation in the UK (PHE 2013).
2.0 Management of viral gastroenteritis
Clinical manifestations
Noroviruses and human rotaviruses cause a gastrointestinal infection which is characterised by: acute onset of non-bloody watery diarrhoea and/or vomiting (which if present is often ‘projectile’).
Also present may be: abdominal cramps, myalgia, headache, malaise and a low grade fever in up to 50% of cases.
Incubation period
Usually 12-48 hours.
Reported as early as 10 hours post exposure.
Infectious dose
Very small, between 10-100 virus particles.
Modes of transmission
Contact via the faecal-oral route and ingestion of aerosolised vomit contaminated with norovirus/ rotavirus.
Direct Contact
Hands come into contact with faecal matter or vomit and subsequently touch the mouth. Hand hygiene using soap and water is vital to prevent spread, especially after using the toilet and prior to meals.
Indirect Contact
Hands come into contact with contaminated equipment or contaminated surfaces and subsequently touch the mouth.
Consumption of faecal contaminated food or water.
Duration of illness
Gastrointestinal symptoms usually resolve within 2-3 days – but 40% of patients can still be symptomatic at 4 days.
Period of infectivity
Patients and staff should be considered infectious whilst they are symptomatic, and continue isolation (or exclusion from work) until they are symptom-free for a minimum of 48 hours or stools have returned to their normal (pre-infection) pattern for 48 hours.
Noroviruses can be detected in stools even after symptoms have resolved and stools have returned to normal. The impact of this on cross-transmission is unknown. Immunocompromised patients can excrete the virus for considerable periods of time.
Patient Placement
Patients with a suspected infectious cause of diarrhoea/ diarrhoea and vomiting, must be source-isolated in a single room with dedicated toilet facilities (ideally en-suite).
Refer to the NIPCM chapter on Transmission-Based Precautions, and Trust guideline IPC04: Isolation of Patients for contact isolation practice guidance.
Definition (Cases)
Possible viral gastroenteritis case:
A patient (or staff member) who, within a 24-hour period has, 3 or more episodes of non-bloody diarrhoea of a suspected infectious
cause, AND/OR, 2 or more episodes of vomiting, without having any other obvious cause for symptoms.
Confirmed viral gastroenteritis case:
A person (or staff member) who, within a 24 hour period has, 3 or more episodes of non-bloody diarrhoea of a suspected infectious cause, AND/OR, 2 or more episodes of vomiting, without having any other obvious cause for symptoms AND who has tested positive for norovirus or rotavirus.
*In the absence of other causes, projectile vomiting and pyrexia is a diagnosis of norovirus.
Specimens
Clinical teams should report cases of suspected viral gastroenteritis to the IPC Team.
Send an unformed stool (Bristol Stool chart Type 5-7) sample for C. difficile toxin testing and PCR, to rule out infectious causes of diarrhoea that require treatment.
If norovirus is suspected, complete the ‘Suspected Viral Gastroenteritis Outbreak record’ (Appendix A) and return to the IPC Team, who will review and arrange for norovirus testing of samples received.
Rotovirus tests on stool samples sent from Paediatric patients, can be requested by clinical teams on Epic.
To note, rotavirus can be detected on PCR testing of stool samples sent from recently rotavirus-immunised children. Diagnosis of infection should be based on correlation of the result with clinical signs and symptoms of rotavirus infection.
Definition (Outbreak)
Two or more linked cases of norovirus associated with the same healthcare setting over a specified time-period.
Outbreak reporting
Outbreak management will be guided by the IPC Team – refer to IPC26: Outbreak Management Plan.
Closure of an inpatient ward due to an outbreak of viral gastroenteritis must only be on the advice of the IPC Team/ Consultant Microbiologist.
The IPC Team report outbreaks of norovirus via the UK Health Security Agency norovirus outbreak reporting portal.
Severity of illness
Usually self-limiting and considered mild.
Mortality as a consequence of norovirus is rare, however is of higher risk in frail, elderly patients with co-morbidities.
Patient assessment
Patients must be regularly assessed for infection throughout their stay this must be documented in their notes.
Viral gastroenteritis can cause rapid dehydration particularly in elderly patients. Therefore, symptomatic patients should have their fluid balance monitored (both stool chart and fluid chart on Epic) and receive rehydration as necessary.
Treatment
There is no specific treatment for viral gastroenteritis, other than letting the illness run its course, and maintaining hydration.
Assuming bacterial causes (e.g. C. difficile, Campylobacter, Salmonella) have been ruled out, anti-emetics may be advised for patients whose vomiting symptoms preclude oral rehydration.
Environmental survivability
Noroviruses can survive on any surface including equipment for at least a week and even on refrigerated food for up to 10 days.
Discharge and Transfer restrictions
A patient may be discharged from hospital to their own homes providing relatives/carers are aware of any precautions required to reduce the risk of transmission in the community.
If symptoms develop after discharge from an area with a known viral gastroenteritis outbreak, patients/carers should inform their GP.
Avoid transferring any patient from a closed ward, bay or care setting to other hospitals/clinical areas/care homes unless there is a clinical need/priority (the receiving clinical area/care home/hospital must be fully informed of any precautions required to reduce the risk of transmission in the community).
If a person requires transport service/ambulance they must be informed of any precautions required to reduce the risk of transmission. Persons who are 48 hours symptom free may travel with others.
Visiting
A ward affected by viral gastroenteritis outbreaks may consider temporary suspension of visiting to all but essential visitors, to reduce the risk of further spread. This must be discussed with IPC Team before implementing.
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Staff should inform visitors to the ward, of the reason for ward closure, to enable their choice of whether to visit or not.
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Visitors should not routinely wear gloves or aprons. They should be advised to clean their hands before entering and when leaving the ward. Soap and water should be used after visiting patients with symptoms or diarrhoea and/ or vomiting.
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If visitors or any of their family members have had diarrhoea and/or vomiting, they should wait until 48 hours after their last symptoms before visiting the hospital (Norovirus Working Party 2012).
Full version control record
This guideline has been registered with the trust. However, clinical guidelines are guidelines only. The interpretation and application of clinical guidelines will remain the responsibility of the individual clinician. If in doubt contact a senior colleague or expert. Caution is advised when using guidelines after the review date. This guideline is for use in Frimley Health Trust hospitals only. Any use outside this location will not be supported by the Trust and will be at the risk of the individual using it.
Version Control Sheet
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