Hundreds of thousands of individuals could also be infected annually by animals carrying coronaviruses associated with the one that causes Covid-19 annually in China and South-east Asia, consistent with a study emphasizing the continued pandemic threat from spillover events.
An average of 400,000 such infections occur annually, most going unrecognized because they cause mild or no symptoms and aren’t easily transmitted between people, researchers of the EcoHealth Alliance and Singapore’s Duke-NUS school of medicine said during a study released on Thursday (Sept 9) before referee and publication.
Still, each spillover represents a chance for viral adaptation that would cause a Covid-like outbreak. The question of where and the way the virus that causes Covid-19 emerged has become particularly contentious, with some leaders blaming a hypothetical leak from a lab in Wuhan, China that studies the pathogens.
The research, supported by the US National Institute of Allergy and Infectious Diseases, builds on evidence that bats are the most host animals for viruses like Sars-CoV-2 which people living near their roosts are especially vulnerable to.
“This is perhaps the primary plan to estimate how often people are infected with Sars-related coronaviruses from bats,” said Mr. Edward Holmes, an evolutionary biologist at the University of Sydney who wasn’t involved within the research.
Humans are continually exposed to bat coronaviruses, he said. “Given the proper set of circumstances, one among these could eventually cause a disease outbreak.”