Chinese lab conducted extensive research on deadly bat viruses, but there is no evidence of accidental release

By Joby Warrick, Ellen Nakashima, Shane Harris and Anna Fifield
April 30, 2020 at 7:29 p.m. EDT

For nearly a decade, a team of scientists from Wuhan, China, crisscrossed southern Asia in a high-stakes search for bats and the strange diseases they harbor. They crawled through caves, catching the razor-toothed mammals with nets and scooping up liters of their excrement. They trapped insects and mice living near bat roosts and collected blood from villagers who hunt bats for food or folk medicine.

They returned to their state-of-the-art laboratory in central China with tubes and vials containing known killers — pathogens associated with diseases that are deadly in humans — and also a few surprises. On multiple occasions, their takings included exotic coronaviruses previously unknown to science.

The highlights of the Wuhan researchers’ work on bat viruses are spelled out in more than 40 published studies and academic papers that describe a sprawling, ambitious effort to document the connection between bats and recent disease outbreaks in China. The experiments were intended to illuminate how dangerous pathogens sometimes jump from animal hosts to humans. But experts say the research also carried an implicit risk: the possibility that the lab itself could facilitate the spread of the very diseases the scientists were trying to prevent.

On Thursday, the U.S. intelligence community released an assessment formally concluding that the virus behind the coronavirus pandemic originated in China. While asserting that the pathogen was not man-made or genetically altered, the statement pointedly declined to rule out the possibility that the virus had escaped from the complex of laboratories in Wuhan that has been at the forefront of global research into bat-borne viruses linked to multiple epidemics over the past decade.

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Yet, despite the intense scrutiny, the novel coronavirus’s origins remain as murky now as they did when the first cases emerged in China five months ago. While intelligence analysts and many scientists see the lab-as-origin theory as technically possible, no direct evidence has emerged suggesting that the coronavirus escaped from Wuhan’s research facilities. Many scientists argue that the evidence tilts firmly toward a natural transmission: a still-unknown interaction in late fall that allowed the virus to jump from a bat or another animal to a human.

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