Norovirus recovery from floors and air after various decontamination protocols

Abstract

Background: The dispersal of airborne norovirus (NoV) particles from the floor after contamination with faeces or vomit is a challenge for infection control, as this pathogen is infectious at low doses. Therefore, it is imperative to establish a safe protocol for floor decontamination.

Aim: To assess the presence of residual NoV-GII particles on floors and airborne particles following various floor decontamination procedures.

Methods: Two types of floor (vinyl and granite) were contaminated intentionally with 10% human faeces, positive for NoV-GII. Two decontamination protocols were implemented: cleaning followed by disinfection using 1% sodium hypochlorite, and cleaning followed by disinfection using a manual ultraviolet C (UV-C) light device. Swab samples were taken from the floors, and air samples were obtained using an air sampler. The TaqMan method for real-time reverse transcription-quantitative polymerase chain reaction was employed for analysis.

Findings: The disinfection protocol using 1% sodium hypochlorite after cleaning proved to be more effective than cleaning followed by UV-C light exposure (P<0.001). Viral particles were detected in 27 of 36 air samples after cleaning, with no significant difference between the two floor types. On average, 617 genome copies/sample were identified in air samples after cleaning, but the number decreased gradually after disinfection.

Conclusion: NoV-GII can be aerosolized during floor cleaning, and its particles may be inhaled and then swallowed or can settle on surfaces. Therefore, residual viral particles on floors must be fully eliminated. Cleaning followed by 10 min of 1% sodium hypochlorite disinfection proved to be the superior decontamination protocol.

Keywords: Airborne transmission; Disinfection; Environmental decontamination; Norovirus.