title: Transfer of noroviruses between fingers and fomites and food products.
abstract: Human norovirus (NoV) contaminated hands are important routes for transmission. Quantitative data on transfer during contact with surfaces and food are scarce but necessary for a quantitative risk assessment. Therefore, transfer of MNV1 and human NoVs GI.4 and GII.4 was studied by artificially contaminating human finger pads, followed by pressing on stainless steel and Trespa® surfaces and also on whole tomatoes and cucumber slices. In addition, clean finger pads were pressed on artificially contaminated stainless steel and Trespa® surfaces. The transfers were performed at a pressure of 0.8-1.9 kg/cm(2) for approximately 2s up to 7 sequential transfers either to carriers or to food products. MNV1 infectivity transfer from finger pads to stainless steel ranged from 13 ± 16% on the first to 0.003 ± 0.009% on the sixth transfer on immediate transfer. After 10 min of drying, transfer was reduced to 0.1 ± 0.2% on the first transfer to 0.013 ± 0.023% on the fifth transfer. MNV1 infectivity transfer from stainless steel and Trespa® to finger pads after 40 min of drying was 2.0 ± 2.0% and 4.0 ± 5.0% respectively. MNV1 infectivity was transferred 7 ± 8% to cucumber slices and 0.3 ± 0.5% to tomatoes after 10 min of drying, where the higher transfer to cucumber was probably due to the higher moisture content of the cucumber slices. Similar results were found for NoVs GI.4 and GII.4 transfers measured in PCR units. The results indicate that transfer of the virus is possible even after the virus is dried on the surface of hands or carriers. Furthermore, the role of fingers in transmission of NoVs was quantified and these data can be useful in risk assessment models and to establish target levels for efficacy of transmission intervention methods.
authors.affiliation: Laboratory of Food Microbiology, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands; Laboratory for Infectious Diseases and Screening, Center for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
authors.forename: Era
authors.initials: E
authors.lastname: Tuladhar
authors.forename: Wilma C
authors.initials: WC
authors.lastname: Hazeleger
authors.forename: Marion
authors.initials: M
authors.lastname: Koopmans
authors.forename: Marcel H
authors.initials: MH
authors.lastname: Zwietering
authors.forename: Erwin
authors.initials: E
authors.lastname: Duizer
authors.forename: Rijkelt R
authors.initials: RR
authors.lastname: Beumer
mesh_terms: D017250:Caliciviridae Infections / Q000635:transmission*; D018553:Cucumis sativus / Q000821:virology; D004866:Equipment Contamination; D005260:Female; D005385:Fingers / Q000821:virology*; D050456:Fomites / Q000821:virology*; D005516:Food Microbiology; D006801:Humans; D018551:Solanum lycopersicum / Q000821:virology; D008297:Male; D029322:Norovirus / Q000502:physiology*; D013193:Stainless Steel
chemical_list: D013193:Stainless Steel
keywords: Finger pad; MNV1; Norovirus; Surfaces; Transmission