Fig. 1

Examination of the effect of UV irradiation on IAV infectivity by plaque assay. IAV suspensions were irradiated with a UV lamp for increasing periods of time between 15 s to 5 min. IAV infectivity was measured by plaque assay using MDCK cells. a The representative pictures of plaques of No UV, 2 min, and 5 min are shown. Dilution factors of IAV are displayed on the top of each well. b The titers are plotted on the graph and shown as pfu/mL (●). Assays were repeated four times and values represent the mean ± standard error. No plaque formation was observed after 4 and 5 min of irradiation and these were defined as not detected (ND). The ratio of experiments in which plaque formation was observed is also plotted on the graph (◆)