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

Aims: 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 aerosolized 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 aerosolized MNV than 3P and NIO. A higher recovery was also found for GSP compared with TC, albeit not significantly. Finally, recovery of aerosolized 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.