Viral Gastroenteritis

Guidance

This information is, in part, adapted from "Gastric Flu Outbreaks in Hotels - Pilot Guidelines for FTO Members" by Prof. Rodney Cartwright, Micro Diagnostics (UK) Ltd., 55 Holford Road, Merrow, Guildford GU1 2QE. 

Clinical Features
The main symptom is vomiting. The vomiting is usually of sudden onset and may be projectile resulting in widespread soiling. Diarrhoea tends to be short-lived and less severe than with other causes of gastro-enteritis. Other symptoms include nausea, abdominal cramps, headache, muscle aches, chills and fever. Symptoms generally last between one and three days and recovery is usually rapid thereafter. The severity of the vomiting may be result in dehydration, especially in the elderly and very young.  

The cause of the illness
The illness is caused by the "Norwalk like virus" (NLV). The virus was first recognised as the cause of an outbreak of non-bacterial gastro-enteritis in a primary school in the town of Norwalk, Ohio, U.S.A in 1969. They were termed for many years as small round-structured viruses (SRSVs) but are now officially referred to as Norwalk-like viruses (NLVs).  

Where does the virus come from and how is it spread?
The virus is primarily spread from the vomit of a sick person. When sudden projectile vomiting occurs a fine mist of virus particles passes into the air and can readily be spread to others in a wide area. Similar spread can also occur from diarrhoea although the main risk for this will be in toilet areas.  

Environmental contamination from both vomit and diarrhoea can occur with subsequent transfer of the virus onto people's hands. More importantly, any food item can potentially transmit the virus if handled by an infected or contaminated person who is responsible for touching or preparing food. 

The virus has also been associated with contaminated shellfish especially raw oysters and similar bivalve molluscs. Raw shellfish including oysters are a well-recognised hazard and is associated with outbreaks of viral gastro-enteritis. All prawns and shellfish should be thoroughly cooked.   

Food
It is extremely important to wash your hands before eating.

If anyone vomits in an area with uncovered food there is a risk that the virus will have contaminated this food and surrounding surfaces. The food must be discarded, all surfaces thoroughly cleaned with a disinfectant solution  

Vomit and Faeces Cleaning
Every food establishment and shops selling food should have a written policy concerning the housekeeping arrangements for clearing up vomit or faeces. The policy should include the following points:

• In the event of an outbreak consideration should be given to having a special trained cleaning team available at all times. The names of suitably trained persons or companies should be included in the policy.
• In the event of a member of staff or a member of the public having a vomit/ faecal accident the area must be cleaned as a matter of urgency. The area where such an incident has occurred should be closed, or cordoned off, for at least one hour and all windows opened to allow thorough air circulation.
• In the event of an outbreak the frequency of cleaning public toilets should be increased to at least every hour during the day and evening. All surfaces in the toilet areas should be cleaned with a bleach disinfectant using disposable cloths.

Cleaning and disinfection procedures.
As NLV is a very hardy organism, it is necessary to use a dilute bleach solution or steam-cleaning of surfaces which have been or may have been soiled by someone getting sick or having a faecal accident, to ensure that the virus has been destroyed.

NOTE: ORDINARY WASHING WITH SOAP AND DISINFECTANT IS NOT SUFFICIENT. 

Hypochlorite (Bleach) Solution
The recommended level of 1000ppm is 0.1% hypochlorite or bleach solution. Bleach of this concentration is most easily made up by adding 2 capfuls of ordinary household bleach to a 1 gallon bucket of water. 

Cleaning Cloths

• Disposable clothes should be used.
• Separate coloured cloths should be used in toilet areas. 

Guidance on cleaning up vomit and faeces.
Individuals, who clean up vomit or faeces, in order to minimize the risk of infection to themselves, should use the following precautions:

• Wear disposable gloves and plastic disposable apron.
• Use paper towels to soak up excess liquid. Transfer these and any solid matter directly into a plastic waste bag.
• Clean the soiled area with detergent and hot water, using a disposable cloth.
• Disinfect the contaminated area with freshly made 0.1% hypochlorite solution. (Note that bleach is corrosive and may bleach furnishings and fabrics)
• Dispose of apron and cloths into a waste bag for burning.
• Wash hands thoroughly using soap and water for at least 1 minute and then dry them.

Treatment of specific materials

• Contaminated linen and other materials should be placed carefully into separate laundry bags. They should be washed in a hot wash. If an outside laundry is used they should be consulted, as the laundry is potentially infectious.
• Soft furnishings such as chairs can be placed outside in the sun for a few hours.
• Mattresses that have not been soiled can be thoroughly aired in the sun for a few hours. Soiled mattresses should be removed for steam-cleaning.
• Contaminated carpets should be cleaned with detergent and hot water, then disinfected with hypochlorite (if bleach-resistant) or steam cleaned.
• Contaminated hard surfaces should be washed with detergent and hot water, using a disposable cloth, then disinfected with 0.1% hypochlorite solution. Cloths should be disposed of as waste. Non-disposable mop heads should be laundered in a hot wash.
• Horizontal surfaces, furniture and soft furnishings in the vicinity of the soiled area should be cleaned with detergent and hot water, using a disposable cloth.
• Fixtures and fittings in toilet areas should be cleaned with detergent and hot water using a disposable cloth, then disinfected with 0.1% hypochlorite solution.

Cleaning up vomit in food preparation areas

• Using the above principles, carefully remove all vomit and clean the area.
• Disinfect the food preparation area (including vertical surfaces) with a freshly prepared 0.1% solution.
• Destroy any exposed food, food that may have been contaminated and food that has been handled by an infected person.

Last reviewed: January 2015