Guidelines for the public health management of gastroenteritis outbreaks due to norovirus or suspected viral agents in Australia

Appendix 5.2: Guidance for managing suspected norovirus outbreaks in aged-care facilities

Page last updated: 2010

What is viral gastroenteritis?

Viral gastroenteritis is a common cause of diarrhoea and vomiting. Other symptoms may include nausea, stomach cramps, fever, headache and muscle aches. It takes about 24– 48 hours for symptoms to develop and the illness may last a day or two. The illness causes embarrassment, and disruption to normal activities, and can be serious in the very young or the very old. However, it generally settles without further problems, and other than maintaining a good fluid intake there is no specific treatment. Outbreaks can occur in aged-care facilities, childcare centres, restaurants and hotels.

How is gastroenteritis spread?

Viral gastroenteritis is highly infectious. It can be spread in the following ways:
  • by person-to-person contact (for instance when the virus is on people’s hands)
  • by airborne spread. (When a person vomits, large amounts of virus particles pass into the air in invisible droplets and can be passed on to other people in the same room)
  • by swallowing contaminated food or drink.
Someone with viral gastroenteritis is potentially infectious while they have the symptoms and for at least 48 hours after the symptoms have stopped (longer in the elderly).

Anyone who has had diarrhoea and vomiting for more than 24 hours should be seen by a doctor. The diagnosis of viral gastroenteritis is normally made on the basis of symptoms and through the testing of faeces or vomit.

The onset of vomiting in a number of people over a period of 1–3 days suggests that the infection is spreading within the establishment. The following specific actions should be implemented to stop the spread of infection.

PDF printable version of Figure 4: Flow chart to guide aged-care facilities actions for managing (presumed) norovirus gastroenteritis outbreaks (PDF 232 KB)

Recognising an outbreak

A gastroenteritis outbreak is defined as two or more cases of vomiting or diarrhoea over a 24 hour period, not counting noninfectious causes (e.g. use of aperients, known bowel problem, etc.). Recognising an outbreak helps institute measures that control the spread of infection.

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Reporting to the Public Health Unit

The local Public Health Unit (PHU) should be notified as soon as an outbreak is recognised, and within 24 hours. They will provide further guidance and support in investigating the outbreak as appropriate. Sometimes a site visit will be carried out by the PHU. Unless specified otherwise, the PHU will need to be provided with a daily line-listing (see template in section 5.6) of ill residents and staff, as well as information about any significant developments (e.g. results of laboratory testing, need for hospital admissions, deaths associated with the outbreak etc.).

Laboratory testing

It is important to identify the cause of the gastroenteritis, as some pathogens can indicate foodborne gastroenteritis (Table 4). Samples of diarrhoea/vomit need to be obtained from all new cases until samples from six people (residents or staff) have been collected. These samples should be labelled and dated, and then kept in the fridge (not the freezer) until collected by the pathology courier. A specimen collection form needs to be completed to accompany the specimens to the laboratory.

Table 4: Pathogens that can cause gastroenteritis
Some specific intestinal infections that may indicate food-borne gastroenteritis (if detected, inform PHU immediately):
  • Salmonella
  • Campylobacter
  • Clostridium perfringens
  • Listeria
  • Shiga toxin-producing E. coli (STEC)
  • Staphylococcus aureus
  • Bacillus cereus

Isolation/cohorting

Ideally patients should be nursed in a single room with adjoining bathroom facilities. However, residents should not be moved around the facility to reduce the risk of further spreading the infection. If several patients have the same pattern of infection or are known to be carriers of an outbreak organism then ‘cohort nursing’ may be appropriate. Cohort nursing involves one nurse or group of nurses exclusively caring for the identified cases, while other nurses care for the well patients. Staff working in the affected area should not be relocated to other areas until the outbreak has ceased. Staff from other areas should be discouraged from visiting the restricted area.

People are generally considered to be infectious for at least 48 hours after their symptoms have ceased; the elderly may be infectious for a longer period. The recommended time for isolation of residents and restriction of usual functions of the facility (see below) is for 72 hours after symptoms have settled in the last case. A thorough terminal cleaning needs to be carried out after this time prior to return to normal activities.

Restriction of admissions and ward closures

New residents should not be admitted to the affected ward/unit area until all cases have been free of symptoms for 72 hours. The entire facility may be considered ‘infected’ if the wards or units are not sufficiently separated to prevent the spread of infection.

Transfer of residents

Residents should not be transferred from the facility to other hospitals and institutions during an outbreak unless this is required for their clinical care. If any resident needs to be transferred, the receiving facility must be informed beforehand of the outbreak (e.g. clearly state ‘suspected norovirus’ or ‘current norovirus outbreak at the facility’ and talk to the infection control staff or receiving area at the hospital beforehand). Residents of the facility requiring norovirus-related hospital review or admission can be received back during the outbreak, to be cared for with the usual outbreak-related precautions.

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Staff training

  • Ensure that infection control practices are included in the orientation program for all new employees.
  • Ensure that all staff are aware of the outbreak and their role in containing it.
  • Ensure that all general practitioners looking after residents in the facility are informed about the outbreak as well as the required precautions.
  • Schedule compulsory in-service education on infection control to all staff members.
  • Ensure workplace information and training programs form part of the orientation program for new employees and are regularly repeated for all staff.
  • Ensure that all staff are aware that should a resident require transfer to hospital for any reason, the hospital staff need to be advised of the existence of the outbreak prior to transfer.

Exclusion of staff

Staff are reminded to report if they have any signs or symptoms of gastroenteritis themselves. Staff should not come to work if they are unwell, and are to be excluded until 48 hours after their symptoms have ceased. Also remind medical practitioners and volunteers of this requirement.

Staff handwashing practices

Handwashing is considered the most cost effective and simple method of preventing the spread of infection.

It is important that staff thoroughly wash their hands after removing protective equipment, as studies have shown that lack of hygiene after using gowns, masks and gloves can spread viruses.

Closure of common areas

Access to common areas such as the dining room and day room should be restricted until all unwell residents are symptom free for 72 hours. If the areas within the facility are not suitably separated to prevent the possible spread of infection, then the common areas should either be closed altogether or, if this is impractical, their use should be restricted to well residents only. Unwell residents should be served meals in their own rooms or at a second sitting.

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Relatives/visitors

  • Advise unwell visitors not to visit their relatives.
  • Advise visitors not to visit ‘the affected area’ until further notice (e.g. until all residents in that area are symptom free for 72 hours or the outbreak is declared over).
  • Whether restrictions to visiting pertain only to the affected area, or to the whole facility depends on whether the wards/units are separate enough to prevent further spread of infection.
  • If units are suitably separate, visitors to non-affected areas of the facility may be able to continue to visit but they should be advised to wash hands on arrival and before leaving.
  • Advise non-essential visitors (e.g. visiting therapists, hairdressers, activity staff, etc.) not to visit during the outbreak.
  • Visiting restrictions may need to be lifted in particular circumstances, such as imminent death of a resident. In such an event, visitors may be instructed in infection control and given suitable protective equipment, such as a mask and gloves.

Cleaning

  • Clean the rooms of well residents first.
  • Clean then disinfect all potentially contaminated areas (as described below).These areas include: toilets, showers, dirty utility/pan rooms, chairs, bedside tables, floors, handles, handrails, phones and any surface exposed to hand contact.
  • First clean the potentially contaminated areas with detergent and hot water. Organic matter, such as faeces or vomit, will inactivate sodium hypochlorite (bleach) so prior cleaning is essential.
  • Then disinfect these areas using the freshly made disinfectant solution.
  • Bleach requires direct contact with surfaces for a minimum of 10 minutes.
  • Bathrooms/toilets should be cleaned twice daily and when visible soiling occurs.
  • Wipe down hard surfaces (e.g. handrails) using bleach solution twice daily during outbreak.
  • Shower chairs to be wiped down using bleach solution between residents during the outbreak.
  • Soft furnishings or metal surfaces which might be damaged by a hypochlorite solution should be cleaned with detergent and then left to dry thoroughly.
  • Detachable mop heads should be laundered in a hot wash and left to air dry after use.
  • Non-disposable mop heads should be laundered in a hot wash.
  • Hypochlorite solution is used for disinfecting. Use either hospital-grade disinfectant mixed at a ratio of 50/50 with water (5000 ppm), or freshly constituted household bleach solution (1000 parts per million). For further information, see Appendix 4.

Cleaning up vomit and faeces

  • Spills should be attended to immediately.
  • If someone vomits in a public place, remove all others from the vicinity.
  • Wear appropriate personal protective equipment (see above section).
  • Use paper towels to soak up excess liquid and place in plastic bag.
  • Clean the soiled area with detergent and hot water using a disposable cloth.
  • Disinfect the soiled area with the freshly made disinfectant solution.
  • Dispose of used items as per facility protocol for ‘clinical waste’.
  • Close the area for at least 1 hour.
  • Wash hands thoroughly (see above section).
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Care of cleaning materials

Durable gloves should be worn during cleaning procedures. All cleaning equipment should be washed with detergent and warm water, rinsed and left to air dry, and then stored in a designated area. All remaining diluted cleaning products should be disposed of after use. Colour coding of various items of cleaning equipment is considered the most effective method of restricting equipment to individual areas of a facility e.g. reception, common areas (blue), toilets/bathrooms/dirty utility rooms (red), food service areas (green).

Linen

In order to prevent transmission of infection to staff, soiled linen/clothing should have minimal handling prior to laundering.
  • Used linen should be bagged at the point of generation and promptly removed from patient care areas.
  • Wet/visibly soiled linen should be placed in plastic lined linen bags.
  • Linen bags should not be overfilled.
  • Linen/clothing should not be rinsed or sorted in patient care areas.
  • All soiled linen/clothing should be put through hot wash/hot dry cycles.
It is important to alert laundry staff or laundry contractors that the facility is experiencing an outbreak of gastroenteritis. All staff handling or cleaning soiled linen during an outbreak should use protective equipment to prevent infection.

Outbreak over

The outbreak may be considered over when all cases have been free of symptoms for 72 hours. Notify the PHU for closure of the outbreak.