As a deadly new virus starts spreading in Wuhan, China, so do rumours about a lab there.

In the remote, jungle-covered hills of China’s far-southwestern Yunnan Province, teams of scientists have spent years intensively researching one animal: bats. The scientists are virus hunters, trying to better understand and mitigate the threat of new viruses jumping from bats to other animals and humans, potentially setting off a pandemic.

Their samples of bat droppings are brought back to labs, including the Wuhan Institute of Virology. So when a new coronavirus begins killing people in that same city, questions are raised about whether the people trying to stop a pandemic could’ve accidentally triggered one.

Archive: CBS; The White House; NPR; CGTN; NBC.

Presenter: John Sudworth Series producer: Simon Maybin Editor: Richard Vadon Sound design and mix: James Beard Commissioning editor: Dan Clarke Science advice: Julian Siddle and Victoria Gill Extra production: Eva Artesona and Kathy Long Research support: Zisheng Xu and BBC Monitoring Production coordinators: Siobhan Reed, Helena Warwick-Cross, Sophie Hill, and Debbie Richford Theme and original music: Pete Cunningham, with trumpet by Joss Murray Radio 4 Editor of Editorial Standards: Roger Mahony Head of BBC News - Long Form Audio: Emma Rippon