Dr. Sean Whelan is an expert in the field of negative-strand RNA viruses. He pioneered approaches to genetic manipulation of rhabdoviruses and has exploited that system to study viral entry and gene expression. His lab has exploited VSV vectors in which the glycoprotein is replaced by those of pathogenic viruses such as Ebola to screen haploid human cells in which host genes were inactivated by insertional mutagenesis. This work identified NPC1 as the receptor for Ebola virus and has confirmed that α-dystroglycan is an important receptor for Lassa virus entry. He has productively collaborated with Dr. Cunningham on the host requirements for Ebola virus entry, Dr. Kirchhausen on the uptake of rhabdovirus particles into cells through clathrin mediated endocytosis, and Dr. Harrison on influenza A virus fusion.