The overall goal of our research is to understand the steps in the entry of enveloped viruses into their target cells, as the first step in infection. The focus has been on a group of paramyxoviruses that includes pediatric respiratory pathogens as well as emerging lethal viruses. The fundamental aspects of this research have identified key roles of viral glycoproteins during the receptor binding and entry process, and most recently of the interactions between the two surface glycoproteins during their mediation of membrane fusion. These fundamental findings have led, in the last 5 years, to our design of novel antiviral strategies that target each of the steps in entry. These antiviral approaches, in turn, have yielded valuable tools and reagents for furthering our understanding of basic mechanisms. Current projects in our group include ongoing in-depth basic research on the mechanisms of virus-induced membrane fusion, centered on parainfluenza virus for the most fundamental research, with Nipah virus as a contrasting mechanism. The applications of our findings to preventing infection include not only parainfluenza virus and the emerging Nipah virus, but also other pediatric respiratory pathogens (Respiratory Syncytial virus, measles virus, influenza) as well as other emerging lethal viruses (Ebola, Junin, Marburg).