Fig. 3. YFV-17D tissue titres. IFNAR^−/− mice were inoculated (a) intramuscularly (IM) or (b) intraperitoneally (IP) with 10⁴ p.f.u. YFV-17D and tissues were harvested at disease onset (days 6–8 p.i.) for mice exhibiting viscerotropic (V) or neurotropic (N) disease, or day 8 p.i. for mice with no clinical signs of disease (NC). Viral titres were quantified using BHK-J cell plaque assays. Data are shown as p.f.u. per tissue, except for blood titres, which are shown as p.f.u. ml⁻¹. Results are from five to 20 mice per condition, with the mean indicated by a horizontal line. Differences that are statistically significant are shown by asterisks (P<0.05, Student’s t-test). nd, Titres below the detection limit of ~10 p.f.u. per tissue.