Cidofovir treatment equalizes virus titers. B6, IFN-γ−/−, and Prf−/− mice were infected with 106 PFU VACV i.p. and were either left untreated (A) or treated 2 dpi with 400 μg of cidofovir i.p. (B). At 7 dpi, virus titers in the ovaries, spleen, and liver were determined. The quantitation of virus titers in the treated and untreated groups are from a different experiment than that for which data are shown in Fig. 3. Data are results for individual mice. Horizontal lines and error bars indicate the mean ± SEM for each group and are representative of two independent experiments. *, P = 0.05.