CORONAVIRUS OUTBREAK MAY HAVE STARTED AS EARLY AS SEPTEMBER, SCIENTISTS SAY

Newsweek 18 April 2020 - by Hannah Osborne

The coronavirus outbreak could have started as early as mid-September, and the Chinese city of Wuhan may not be where it began, a scientist looking at the origins of the disease has said.

Geneticist Peter Forster, from the U.K.'s University of Cambridge, is leading a research project to understand the historical processes that led to the COVID-19 pandemic. Ultimately, they hope to identify the first person who got the virus and served as the source for the initial outbreak.

By analyzing networks, they have so far been able to chart the spread of the virus, including the genetic mutations, as it moved from China to Australia, Europe and the rest of the world.

They have created a network analysis using over 1,000 coronavirus genomes. This includes patient infection date and the "type" of virus the person was infected with. There are three types—A, B and C. A is closest to the coronavirus found in bats and is thought to be the original human virus genome. This type was found in Chinese and American individuals, with mutated versions in patients from Australia and the U.S.

However, A was not the virus type found in most cases in Wuhan, the city in China where COVID-19 was first identified. Instead, most people there had type B. Researchers suggest there was a "founder event" for type B in Wuhan. Type C, the "daughter" of type B, is what was identified in early cases in Europe, as well as South Korea, Singapore and Hong Kong—but appears absent from mainland China.

Medical workers check information as they take swab samples from people to be tested for the COVID-19 novel coronavirus in Wuhan, China's central Hubei province on April 16, 2020. - China has largely brought the coronavirus under control within its borders since the outbreak first emerged in the city of Wuhan late last year. (Photo by Hector RETAMAL / AFP) (Photo by HECTOR RETAMAL/AFP via Getty Images)Based on the data Forster and his colleagues have collected, the coronavirus outbreak appears to have started between September 13 and December 7. "This assumes a constant mutation rate, which is admittedly unlikely to be the case, and the time estimate could therefore be wrong," he told Newsweek. "But it is the best assumption we can make at the moment, pending analysis of further patient samples stored in hospitals during 2019."He said it is possible the outbreak did not originate in Wuhan, as until January 17, almost all the isolates were type B. In Guangdong, a province about 500 miles from Wuhan, seven of the 11 isolates were type A. "These case numbers are small because few genomes are available for the early stage of the outbreak, before the Chinese New Year travel pre-January 25 would have started mixing patterns up geographically," Forster said.He and colleagues published research into their network in PNAS on April 8.The first known coronavirus case has been traced back to November 17. According to a report in the South China Morning Post, government data shows a 55-year-old from the Hubei province, which Wuhan is the capital of, was the first known case of COVID-19. It is thought the virus jumped from an animal—likely a bat—into humans at some point. When and where this happened is not known. In December, the first cluster of cases was traced back to a seafood market in Wuhan, leading some to suggest this is where the virus first emerged. But as we learn more about the virus, this version of events appears less likely. A study published in the Lancet showed some of the first people infected with the virus did not have direct contact with the market.

Since these first cases at the end of last year, over two million people have been confirmed to have had COVID-19. According to Johns Hopkins University, it has spread to 185 countries and regions, with almost 150,000 deaths recorded.

Identifying the original source of the virus, Forster said, is necessary to ensure it does not happen again. Understanding the different types of virus and what role they play in the spread of COVID-19 is "one of the urgent questions to be looked at," he said.