We use molecular virology approaches and mouse models of infection to understand innate immune mechanisms that control arbovirus pathogenesis (e.g. West Nile, Zika, and La Crosse viruses). Bat flaviviruses have unusual vector/host relationships; understanding the viral and host factors that determine flavivirus host range is important for recognizing potential emerging infections. We are studying the antiviral effects of interferon lambda (IFN-λ) at barrier surfaces, including the blood-brain barrier and the skin. We also use mouse models of atopic dermatitis and herpes simplex virus infection to understand the effects of IFN- λ in the skin.