In spite of their apparent simplicity, viruses remain a major threat to humanity. The research of the Virology Unit at the Department of Medicine and Life Sciences (MELIS) leaded by Juana Diez (Molecular Virology group) and Andreas Meyerhans (Infection Biology group) studies fundamental basic and translational aspects of the biology of pathogenic viruses. These include (i) how viruses take over cells (ii) how they interact with the infected host at a system level, and (iii) how to develop more effective antiviral treatments.