Before entering the cave, the small team of scientists pull on hazmat suits, face masks and thick gloves to cover every inch of their skin. Contact with bat droppings or urine could expose them to some of the world’s deadliest unknown viruses.
Equipped with headlights, they set their nets up at the entrance of the dark opening overhung with bamboo trees, which is part of a vast system of limestone caves in China’s south-western Yunnan province.Then they patiently wait for dusk. When the sun sets, thousands of bats fly out of the caves, looking for food — and straight into their nets.
The scientists collect the nets and carefully put the bats to sleep with a mild anesthetic, before delicately extracting blood from a vein on their wings. “We also carry out oral and faecal swabs and gather droppings,” says Peter Daszak, who presides over EcoHealth Alliance, an American NGO which specializes in detecting new viruses and pandemic prevention.The entrance to one of the caves in a vast limestone cave system in Yunnan province, China, which Eco Health Alliance has been exploring for over 10 years.
Daszak is a virus hunter. Over the past 10 years, he has visited over 20 countries trying to prevent the next big pandemic by searching bat caves for new pathogens. More specifically, new coronaviruses.
The findings of Daszak, and others like him, inform an open-source library of all known animal viruses, from which scientists can forecast which strains are most likely to spill over to humans, in order to ready the world for a new pandemic like Covid-19.
“We (have) collected more than 15,000 bat samples, which led to the identification of around 500 new coronaviruses,” he says.
And one of those, found in a cave in China in 2013, was a possible ancestor of Covid-19.
Coronavirus research
Before the 2003 SARS epidemic, research into coronaviruses didn’t attract much attention. “It wasn’t seen as a sexy branch of medical research,” says Wang Linfa, a virologist from Duke-NUS in Singapore, who develops the tools used to analyze the samples collected by EcoHealth Alliance.
Only two human coronaviruses had been identified back then, both discovered in the 1960s.
In 2009, Predict was founded. Funded by USAID, it is led by University of California Davis, alongside EcoHealth Alliance, the Smithsonian Institution, the Wildlife Conservation Society and Metabiota, a Californian company which has developed an epidemic tracker.To catch the bats, EcoHealth Alliance’s scientists have to set up nets at the entrance of the cave. To avoid any contact with the bats, they wear hazmat suits, a respirator and gloves.
The initiative was tasked with identifying and responding to new zoonotic diseases — including coronaviruses — before they spread to humans. Over the course of its 10 years in operation, it was awarded around $200 million dollars.
Since its founding, five more human coronaviruses have been identified, including Covid-19. Daszak estimates that bats harbor up to 15,000 coronaviruses, only a few hundred of which are currently known.
Daszak’s organization focuses on southwest China, more specifically on the aforementioned limestone cave system in Yunnan province, known for its large bat population.
“We targeted China initially because we were looking for the origins of SARS,” he explains. “But then we realized that there were hundreds of other dangerous coronaviruses there so we decided to shift our attention to finding them.”EcoHealth Alliance’s team take samples from a bat. Over the past decade, they have collected 15,000 bat samples.
Predict operates in 31 countries. Another team of virus hunters, belonging to the Smithsonian Institution, has started focusing on Myanmar and Kenya. “So far, we were able to identify six novel coronaviruses in Myanmar,” says Suzan Murray, who leads the Smithsonian Institution’s Global Health Program.
“These are areas with lots of wildlife biodiversity, a growing human population encroaching on the natural habitat, good travel networks and a large amount of livestock, which means there is a high potential for virus spillovers between species,” says Dawn Zimmerman, who leads some of the Smithsonian Institution’s virus sampling expeditions.
