IFNAR1 and viral infectious disease: Although mortality was significantly increased in WEEV-eGFP-infected Ifnar−/− mice compared with similarly infected WT animals, Ifnar−/− mice survive WEEV infection up to 5 to 6 dpi (Fig. S4B), and viral infection was undetectable in brain tissues of either WT or Ifnar−/− mice at 1 dpi (Fig. S4E).