Purpose: The aims of this study were to develop a method to evaluate HuNoV transmission quantitatively using a surrogate agent and to clarify their transmission on the basis of activities of daily living.
Methods: Virus-like particles (VLPs) of the HuNoV TCH strain used as the surrogate agent were produced using a baculovirus expression system. Stainless steel plates contaminated with 4 ng of VLPs (corresponding to 2.2 × 108 of HuNoV particles) were wiped with a piece of paper or cotton cloth wet with sterilized water, which was then used to wipe other new stainless steel plates. The VLPs were collected from each stainless steel plate and quantified by ELISA (n = 4).
Results: The amounts of VLPs remaining on the stainless steel plates after the first wiping with the piece of wet paper or cotton cloth were 0.39±0.18 and 0.46±0.14 ng, respectively. The amounts of VLPs transmitted to the new stainless steel plates after spreading with the same piece of paper or cloth were 0.070±0.034 and 0.34±0.050 ng, respectively, both of which corresponded to more than 102 HuNoV particles, which is the number of particles sufficient to cause infection.
Significance: The evaluation method for HuNoV transmission using VLPs could be effective from the viewpoint of sanitization. The results suggest that wiping could easily transmit sufficient amounts of HuNoVs for infection and cannot remove them completely from the surfaces of materials in living environments.