(A) Bank voles were administered a single 25 mg/kg dose (i.p.) of the indicated nAbs (n=12 from two experiments) or PBS vehicle (n=9 from two experiments) followed by a challenge with PUUV/Suo (500 FFU, s.c.) at 4 h post nAb administration. Animals were sacrificed at 3 days post challenge and serum and organ viral RNA loads were determined by RT-qPCR detecting the PUUV S segment. Bars indicate median. (B) Bank voles were challenged with PUUV/Suo (500 FFU, s.c.) followed by treatment with a single 25 mg/kg dose (i.p.) of the indicated nAbs (n=12 from two experiments) or PBS vehicle (n=11 from two experiments) at 24 h post challenge. Animals were sacrificed at 3 days post challenge, and viral RNA loads were determined as above. Bars indicate median. Untreated versus nAb-treated animals, un-paired Kruskal-Wallis test: **, P=0.0021; ***, P=0.0002; ****, P<0.0001.