This invention provides methods for inhibiting or treating infection by viruses, in particular pox viruses by modulating a kinase, in particular by inhibiting a host cell kinase, involved in mediating viral infection. Methods to identify, validate, and classify the cellular proteins required by viruses during infection of host cells in order to select agents which can inhibit viral infection are described herein. Using a systems biology approach the virus/host cell interaction is studied from initial attachment of the incoming virus to the cell surface, to entry, transcription, replication, biosynthesis, and assembly of progeny particles. The method employs a siRNA screening platform and uses gene silencing to map the ‘viral infectome’—a compilation of cellular proteins that the virus needs to establish infection and drive the infectious cycle. Charting the infectome provides information on the viral biology by the identification of host cell proteins involved in viral infection and allows the development of novel anti-viral drugs that prevent the viruses from establishing productive infection in cells.