A couple of years ago Sam, the almost-5-year-old yacked all over the backseat of the van on a car trip. The polyester carpeting and cotton fabric-covered seats smelled for weeks. We even tried to hose the van out, leaving the doors open for a couple of days (and then a frog set up shop in there).
It was most likely motion sickness that led to Sam’s vomit event, but people with noro puke on all sorts of surfaces. My friend Angie Fraser and colleagues at Clemson just published what happens when you try to inactivate norovirus surrogates on different surfaces including polyester and glass.
Our results indicated that surface and virus type had a significant influence on RE (that’s recovery efficiency – ben). We found that both FCV and MNV exhibited higher RE when inoculated onto glass than either polyester or cotton. In addition, the recovery of both viruses from cotton was significantly lower than that of polyester. Compared with FCV, MNV exhibited a higher recovery from soft porous surfaces; however, it was only significant for cotton. Previous studies have also document- ed the ability of HuNoV surrogates to be recovered with greater efficiency from hard nonporous surfaces than from soft porous surfaces. Viruses may become more tightly bound to soft porous surfaces due to their ability to absorb the virus-containing media and trap viruses in the subsurface.
Recovery and Disinfection of Two Human Norovirus Surrogates, Feline Calicivirus and Murine Norovirus, from Hard Nonporous and Soft Porous Surfaces
Yeargin, Thomas; Fraser, Angela; Huang, Guohui; Jiang, Xiuping
Human norovirus is a leading cause of foodborne disease and can be transmitted through many routes, including environmental exposure to fomites. In this study, both the recovery and inactivation of two human norovirus surrogates, feline calicivirus (FCV) and murine norovirus (MNV), on hard nonporous surfaces (glass) and soft porous surfaces (polyester and cotton) were evaluated by both plaque assay and reverse transcription quantitative PCR method. Two disinfectants, sodium hypochlorite (8.25%) and accelerated hydrogen peroxide (AHP, at 4.25%) were evaluated for disinfection efficacy. Five coupons per surface type were used to evaluate the recovery of FCV and MNV by sonication and stomaching and the disinfection of each surface type by using 5 ml of disinfectant for a contact time of 5 min. FCV at an initial titer of ca. 7 log PFU/ml was recovered from glass, cotton, and polyester at 6.2, 5.4, and 3.8 log PFU/ml, respectively, compared with 5.5, 5.2, and 4.1 log PFU/ml, respectively, for MNV with an initial titer of ca. 6 log PFU/ml. The use of sodium hypochlorite (5,000 ppm) was able to inactivate both FCV and MNV (3.1 to 5.5 log PFU/ml) below the limit of detection on all three surface types. AHP (2,656 ppm) inactivated FCV (3.1 to 5.5 log PFU/ml) below the limit of detection for all three surface types but achieved minimal inactivation of MNV (0.17 to 1.37 log PFU/ml). Reduction of viral RNA by sodium hypochlorite corresponded to 2.72 to 4.06 log reduction for FCV and 2.07 to 3.04 log reduction for MNV on all three surface types. Reduction of viral RNA by AHP corresponded to 1.89 to 3.4 log reduction for FCV and 0.54 to 0.85 log reduction for MNV. Our results clearly indicate that both virus and surface types significantly influence recovery efficiency and disinfection efficacy. Based on the performance of our proposed testing method, an improvement in virus recovery will be needed to effectively validate virus disinfection of soft porous surfaces.