[An outbreak of gastroenteritis caused by norovirus: suspected due to dust transmission].

: A norovirus gastroenteritis outbreak at a wedding reception hall in Nagano Prefecture in April 2008 affected that hall's reception participants and waiters, but not waiters or food handlers at another hall. To determine the infection route, dust in three vacuum cleaners used to clean the venue were tested for norovirus using real-time reverse transcriptase polymerase chain reaction (RT-PCR), with norovirus RNA detected from all three. Sequencing analysis of a 280-nt portion of the capsid region showed that 9 specimens from infected reception participants and waiters and dust samples had 100% nucleotide identity. This suggests that the infection route was dust transmission, that the reception venue floor had been contaminated with norovirus, and that participants and staff had been exposed to norovirus in dust during the wedding reception. Dust thus requires specific attention as a potential infection source because norovirus cDNA copies were 1.7 x 10(4) to 1.6 x 10(5) per gram in dust specimens.