Viral RNA load in the brain after anti-rabies Rab-E8/H7 treatment.

<p>(A) Mice were treated with Rab-E8/H7 (100 µg) by intracerebral injection (IC) 24 hours after intranasal virus inoculation and sacrificed at 7 DPI to assess the viral RNA loads in different brain parts. Rab-E8/H7 VHH treatment significantly reduced the spread of the virus from the front to the posterior parts of the brain (t-test, ** p<0.01, *** p<0.0001). (B) Mice were treated with Rab-E8/H7 at 24 hours before (0.12 µg) or after (100 µg) intranasal virus inoculation. Control mice were mock-treated with irrelevant VHH before virus inoculation. Viral RNA loads were measured at 35 DPI in the brain of survivor mice. Four out of five survivor mice, treated after the virus inoculation, showed residual traces of viral RNA in the brain (ΔCt 5±2.9; *** p<0.0001). These mice had however never developed signs of disease. All mock-treated mice had to be euthanized at 7–9 DPI, because of serious disease, which coincided with high viral RNA loads in their brains (ΔCt≥28).