1 2 Recognition and management of an outbreak of infection

Infection Prevention Solutions

MANAGEMENT OF AN OUTBREAK OF VIRAL GASTROINTESTINAL ILLNESS (e.g. Norovirus)

Viral gastro-intestinal illness is usually caused by norovirus. This was previously called “winter vomiting”, Norwalk virus and small round structured virus (SRSV). Norovirus is a highly contagious gastro-intestinal virus that can be spread by a number of different routes – by direct contact with an affected individual; by aerosolisation of virus particles in body fluids and in particular in vomit; food-borne either from contaminated food or water or by food handlers that are symptomatic; by aerosol droplets (from vomit / faeces) landing onto surfaces and equipment and then being transferred onto hands and then into the mouth.

Norovirus causes a short illness (12 – 60 hours) associated with nausea, profuse vomiting – often projectile, diarrhoea and abdominal pain. Infection is self-limiting but can cause dehydration and deterioration in the very young and elderly.

Outbreaks of norovirus infection in health and care environments can have a devastating effect on activity due to the numbers of affected individuals which includes staff. Business continuity can be adversely affected and acute NHS Trusts have been known to close due to the effect of widespread outbreaks. Often entire communities are affected with schools, nurseries, hospitals, care homes etc. being the most affected due to the large numbers of susceptible individuals in confined environments. The role of the local HPU at PHE in advising in the early detection and management of norovirus outbreaks is crucial to the success of local control measures.

Prompt identification of possible cases of norovirus infection is crucial so that early interventions aimed at limiting spread can be implemented.

CRITERIA FOR SUSPECTING NOROVIRUS OUTBREAK

• Vomiting in > 50% of cases (although sometimes diarrhoea is the prominent symptom) • Duration of illness 12 – 60 hours • Patients AND staff affected (this is a critical criteria) • Cases often occur in clusters up to 48 hours apart due to incubation period of 15 – 48 hours