A review of environmental contamination during outbreaks of Norwalk-like virus

Abstract

Norwalk-like viruses (NLV) commonly cause outbreaks of gastroenteritis in hospitals and can result in major disruption of services. It is considered that contamination of the environment can be a cause of transmission and prolonged or recurring outbreaks. In order to control outbreaks it is important to establish the role of environmental contamination in transmission and the decontamination measures required to prevent this. A review of available evidence is described, showing that despite evidence of environmental contamination with NLV during outbreaks, its presence remains unproven as a cause of prolonged or recurring outbreaks. Evidence suggests that the virus might survive for at least 12 days in carpets and 21-28 days in a dried state at room temperature. NLV has been detected from swabs taken from a variety of sources, including lockers, commodes, toilets, door handles, soft furnishings, frequently handled items and horizontal surfaces below and above 1.5 metres. Expert opinion suggests that carpets should be steam cleaned and curtains should be changed following outbreaks. Hypochlorite 1000 ppm is recommended for disinfecting hard surfaces. Further research of environmental contamination and decontamination activities is required.