Evaluation of air samplers and filter materials for collection and recovery of airborne norovirus

The aim of this study was to identify the most efficient sampling method for quantitative PCR-based detection of airborne human norovirus (NoV). Methods and Results: A comparative experiment was conducted in an aerosol chamber using aerosolised murine norovirus (MNV) as a surrogate for NoV. Sampling was performed using a nylon (NY) filter in conjunction with four kinds of personal samplers; Gesamtstaubprobenahme sampler (GSP), Triplex-cyclone sampler (TC), 3-piece closed-faced Millipore cassette (3P) and a 2-stage NIOSH cyclone sampler (NIO). In addition, sampling was performed using the GSP sampler with four different filter types; NY, polycarbonate (PC), polytetrafluoroethylene (PTFE) and gelatine (GEL). The sampling efficiency of MNV was significantly influenced by both sampler and filter type. The GSP sampler was found to give significantly (P<0.05) higher recovery of aerosolised MNV than 3P and NIO. A higher recovery was also found for GSP compared with TC, albeit not significantly. Finally, recovery of aerosolised MNV was significantly (P<0.05) higher using NY than PC, PTFE and GEL filters. Conclusions: The GSP sampler combined with a nylon filter was found to be the best method for personal filter-based sampling of airborne NoV. Significance and Impact of the Study. The identification of a suitable NoV air sampler is an important step towards studying the association between exposure to airborne NoV and infection.