摘要：This report investigates an outbreak of acute gastrointestinal illness, microbiologically and epidemiolog-ically linked to an aged–care facility and seeks to determine if there was a point source of infection. Aregister of cases that included onset date and time of illness and symptoms was maintained by nursingstaff. Faecal specimens were tested for conventional gastrointestinal pathogens and for humancalicivirus (HuCV). There were 81 cases reported. Specimens were received for testing from 25 cases.Twenty–three of the 25 (92%) specimens were positive for HuCV RNA by reverse transcriptase polymerasechain reaction (RT–PCR). The 2 negative samples contained RT–PCR inhibitors. Descriptive epidemiologysuggested that staffing practices were important in prolonging the outbreak. No point source of infectionwas identified. Instead environmental contamination, aerosol transmission and work practices that failto take account of the natural history of HuCV infection probably contributed to the size (81 cases) andduration (3 weeks) of this outbreak among the residents, staff and visitors of an aged–care facility andtheir contacts. Institutional outbreaks caused by HuCV, formerly called Norwalk–like or small roundstructured viruses, are extremely difficult to control. Infected staff may contribute significantly to theamplification of outbreaks. Rapid confirmation of HuCV infection is now routinely possible usingpolymerase chain reaction diagnostics but progress in laboratory technology has not yet translated intofaster or more effective interventions
关键词：outbreak; Norwalk-like virus; calicivirus; small round structured virus
