Figure 2.

Recovery of infectious virus of BCoV for all surfaces of substrates. The infectious titers of BCoV on surfaces of substrates were measured as TCID₅₀/mL in triplicate at 0, 3, 6, and 18 h after inoculation, using HRT-18G cell culture in 96-well plates. Samples at 0 h were measured immediately after drying. Panels A and B show non-porous and porous substrates, respectively. The rhombuses indicate the mean titers of the inoculated virus. The circles indicate the mean titers of the measured infectious titers. The cross marks indicate no-detection (ND) in in triplicate. During assays, A-5) brass, A-11) nitrile rubber, and B-3) lauan veneer showed cytotoxicity, in which collected virus killed HRT-18G cells without virus when using undiluted collections. When calculating a mean value, ND was regarded as 0 TCID₅₀/mL for non-cytotoxic materials, and 1 log₁₀ TCID₅₀/mL for cytotoxic materials. The LoD and the dotted lines indicate the limit of detection of the assays (LoD) at 0.4 log₁₀ TCID₅₀/mL for non-cytotoxic materials, and 1.4 log₁₀ TCID₅₀/mL for cytotoxic materials. The numbers in parentheses beside the marks including the data below LoD indicate the number of times above LoD in triplicate. The bars indicate the standard deviations of inoculated or collected virus. The lines in bold indicate the declining rate of virus, calculated using linear regression.