FIG 4.
Persistence of MNV infectivity on brasses. Approximately 5 × 105 PFU of infectious virus was applied to 1-cm2 samples of test surfaces and incubated at room temperature. At various time points, virus was removed from the surfaces and assessed for infectious virus by plaque assay as described in the text. The efficacy of these brasses in inactivating norovirus is directly proportional to the copper content; 100% Zn appeared to have some antiviral activity, similar to that of Muntz metal (C28000). The possible antiviral effect of zinc is discussed in the text.