Fig 10. Effects of NS5-V372A and NS5-H386Y variations on IFN-α and β production and viremia in ducklings.

(A, B and C) Two-day-old SPF domestic ducklings (n = 10) were intramuscularly inoculated with the indicated substitution mutant viruses. Blood samples were collected daily through the jugular vein from 1 to 4 dpi for measurement of the levels of IFN-α (A) and IFN-β (B) production and viremia (C). (D) Detection of viral loads in tissues. Two-day-old SPF domestic ducklings (n = 12) were intramuscularly inoculated with the indicated substitution mutant viruses. Three ducklings per group were euthanized daily from 1 to 4 dpi for collection of tissues (spleen, lung, kidney, liver, heart, and brain). Viral loads in each tissue were titrated with TCID₅₀ assays on BHK cells. Data are shown as means ± SD. ***, p < 0.001; **, p < 0.01; *, p < 0.05; ns, no significance, by Student’s t-test.