Management of hospital outbreaks of gastro-enteritis due to small round structured viruses

Small round structured viruses (SRSVs, Norwalk-like viruses, NLVs) are the most common cause of outbreaks of gastro-enteritis in hospitals and also ca use outbreaks in other settings such as schools, hotels, nursing homes and cruise ships. Hospital outbreaks often lead to ward closure and major disru ption in hospital activity. Outbreaks usually affect both patients and staf f, sometimes with attack rates in excess of 50%. For this reason, staff sho rtages can be severe, particularly if several wards are involved at the sam e time. SRSVs may be spread by several routes: faecal-oral; vomiting/aeroso ls; food and water. Viruses may be introduced into the ward environment by any of these routes and then propagated by person-to-person spread. In an o utbreak setting, the diagnosis can usually be made rapidly and confidently on clinical and epidemiological grounds, particularly if vomiting is a prom inent symptom. By the time an SRSV outbreak has been recognized at ward lev el, most susceptible individuals will have been exposed to the virus and in fection control efforts must prioritize the prevention of spread of infecti on to other clinical areas by containment of infected/exposed individuals ( especially the prevention of patient and staff movements to other areas), h and-hygiene and effective environmental decontamination. This report of the Public Health Laboratory Service Viral Gastro-enteritis Working Group reviews the epidemiology of outbreaks of infection due to SRS Vs and makes recommendations for their management in the hospital setting. The basic principles which underpin these recommendations will also be appl icable to the management of some community-based institutional outbreaks. ( C) 2000 The Hospital Infection Society.