To Linfa Wang, PhD, some of the most important unanswered questions about the COVID-19 pandemic lie within slick layers of guano, deep in a hole in the ground.
A virologist with the Duke-NUS Medical School in Singapore, Wang was part of a team of international scientists tasked by the World Health Organization (WHO) with unraveling the origins of the original SARS virus 17 years ago. Now he’s attempting to do the same with the coronavirus that causes COVID-19, known as SARS-CoV-2. While the exact path the virus followed to begin infecting humans isn’t yet known, it’s almost certain to run through bats, which have been the focus of Wang’s work for nearly three decades. And that means looking at a lot of bat poop.
Last year, Wang developed a test to detect antibodies to SARS-type coronaviruses in bat droppings and urine, allowing him to hunt for genetic relatives of SARS-CoV-2. While a study last spring identified similar viruses in bats in southern China, in February, Wang and collaborators also found closely related viruses in bats and pangolins in Thailand. These discoveries indicate that the animal ancestors of the virus responsible for the pandemic may have been circulating over a wider geographic area than previously thought.
And that means a big piece of the COVID-19 origin story is still missing: It’s clear the first cluster of human infections arose in Wuhan, China, but did a human or an animal bring the virus there, and from where?