The coronavirus has already infected more than two million people around the world, and now a new study indicates that the first outbreak may have started as early as September.
Researchers from the University of Cambridge have investigated the virus’ origin to calculate the likely date of the initial outbreak.
Their findings indicate that the outbreak in Wuhan occurred between September 13 and December 7.
Peter Forster, who led the study, said: “The virus may have mutated into its final ‘human-efficient’ form months ago, but stayed inside a bat or other animal or even human for several months without infecting other individuals.
“Then, it started infecting and spreading among humans between September 13 and December 7.”
In the study, which is yet to be peer-reviewed, the researchers analysed coronavirus strains using a mathematical algorithm.
While the virus originated in bats, the scientists found hundreds of mutations between the original Sars-CoV-2 and the one first found in Wuhan.
Typically, a coronavirus usually acquires one mutation per month.
According to the researchers, this indicates that the virus may have quietly been spreading in animals and humans for years, before reaching the form we see today.
Dr Forster said: “If I am pressed for an answer, I would say the original spread started more likely in southern China than in Wuhan.
“But proof can only come from analysing more bats, possibly other potential host animals, and preserved tissue samples in Chinese hospitals stored between September and December.
“This kind of research project would help us understand how the transmission happened, and help us prevent similar instances in the future.”
While there have been several claims that the virus was man-made, a study last month found 'no evidence' of this.
Researchers from Scripps Research analysed the public genome sequence data for the virus, and have found that the virus is the product of natural evolution.
Dr Kristian Andersen, an author of the study, said: “By comparing the available genome sequence data for known coronavirus strains, we can firmly determine that SARS-CoV-2 originated through natural processes.”