Guidance for the management of norovirus infection in cruise ships / Norovirus Working Group.

  • Novovirus Working Group
Date:
2007
Catalogue details

Licence: Open Government Licence

Credit: Guidance for the management of norovirus infection in cruise ships / Norovirus Working Group. Source: Wellcome Collection.

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    1.0 BACKGROUND Norovirus is a major cause of epidemic — acute gastroenteritis and diarrhoea — in children and adults. The cause of illness, norovirus (previously known as Norwalk like or SRSV) was described in 1968 in samples from an elementary school in Norwalk, Ohio. The disease was recognised in 1929 and termed Winter Vomiting Disease because of the increased prevalence in the winter months. It can be detected throughout the year. Noroviruses belong to the family Caliciviridae. At least three genogroups and many genotypes are recognised but there is no agreed nomenclature and different approaches have been used (e.g. Gll.4 or Lordsdale). Noroviruses have been described in cattle, pigs, mice and humans, but the animal strains are quite distinct from human noroviruses. The disease is usually spread from person to person or from the contaminated surroundings. Occasionally food may be implicated in its transmission and a small number of incidents each year are attributed to bivalve molluscs such as mussels, oysters which feed in water polluted with human sewage. symptoms, normally persist for one to two days, and are generally mild but may be more serious in the extremes of age or when other pre existing disease is present. In some individuals the illness may be very short consisting of one or two episodes of vomiting followed by a complete recovery. Even in these individuals the vomit may contain high levels of infectious virus, which may contaminate the environment creating an infection risk for others. Medical treatment is purely supportive and individuals continue to excrete the virus for several days although infectivity is greatly reduced 48 hours after the symptoms cease. Norovirus circulates widely in the population but may only come tc the notice of the health professionals as and when there are outbreaks in semi closed communities such as at schools, hotels, hospitals. Outbreaks on cruise liners have Deen recognised for over 20 years and detailed guidelines produced, but management is not consistent and the aim of this guidance is to produce straightforward and practical advice to aid the industry and pubtic health authorities in managing these outbreaks. 1.1 Assessment of risk The risk of transmitting Norovirus varies through the course of infection. Virus is passed in large amounts in vomit and faeces at the onset of symptoms and there is a considerable risk of transmission during this phase. When the symptoms cease the risks of transmission gradually reduce until about a week from when symptoms stop, but after 48 hours they are unlikely to transmit the disease further if they practice good personal hygiene. Social interaction increases the risk of infection and this may be further exacerbated if those affected are involved in food preparation and handling where there is a potential for