From the start of the pandemic, scientists have tried to determine exactly where and how the novel coronavirus spread to humans. New studies conclude the virus first emerged from a live-animal market in Wuhan, China. One of the authors of a study, Angela Rasmussen, a virologist at University of Saskatchewan's Vaccine and Infectious Disease Organization, joins William Brangham to discuss. PBS NewsHour is supported by - https://www.pbs.org/newshour/about/funders