Antoine Gessain is a medical virologist who earned his MD and PhD in Paris. From 1983 to 1984, he conducted field epidemiological studies on the human retrovirus HTLV-1 in the French West Indies, French Guyana, & Western Africa, discovering the link between HTLV-1 and Tropical Spastic Paraparesis-HTLV-1 associated myelopathy (TSP/HAM). After completing his residency, he spent 2 years as a postdoctoral fellow in RobertC Gallo's Lab. of Tumor Cell Biology at the National Cancer Imstitute (NIH, USA). He then joined the Institut Pasteur, working in the units of Profs G. de Thé and L. Montagnier. Since 2001, he has been the Head of the Epidemiology and Physiopathology of Oncogenic Viruses (EPVO) Unit. He served as President of the Scientific Council of Institut Pasteur from 2011 to 2013. His research focuses on the clinical, epidemiological, and genetic aspects of HTLV-1 and HTLV-3, as well as HHV-8 and Kaposi’s sarcoma. Recently, he has studied the emergence of foamy virus infections from apes to humans. He has published around 300 papers, received numerous awards, and actively contributes to virology education.