An outbreak of viral gastroenteritis associated with consumption of sandwiches: implications for the control of transmission by food handlers

Although food handlers are often implicated as the source of infection in o utbreaks of foodborne viral gastroenteritis, little is known about the timi ng of infectivity in relation to illness. We investigated a gastroenteritis outbreak among employees of a manufacturing company and found an associati on (RR = 14.1, 95 % CI = 2.0-97.3) between disease and eating sandwiches pr epared by 6 food handlers, 1 of whom reported gastroenteritis which had sub sided 4 days earlier. Norwalk-like viruses were detected by electron micros copy or reverse transcriptase-polymerase chain reaction (RT-PCR) in stool s pecimens from several company employees, the sick food handler whose specim en was obtained 10 days after resolution of illness, and an asymptomatic fo od handler. All RT-PCR product sequences were identical, suggesting a commo n source of infection. These data support observations from recent voluntee r studies that current recommendations to exclude food handlers from work f or 48-72 h after recovery from illness may not always prevent transmission of Norwalk-like viruses because virus can be shed up to 10 days after illne ss or while exhibiting no symptoms.