Coronavirus may have started spreading as early as September, say British scientists who are studying its mutations

The coronavirus may have started spreading as early as mid-September and Wuhan may not have been where the pandemic started, British scientists believe.

A team of University of Cambridge researchers are trying to trace the source of the virus by mapping its genetic history to identify the first person who was infected.

Geneticist Dr Peter Forster and his team have also gathered data that the outbreak appears to have started at some point between September 13 and December 7. 

The reserachers have been able to chart the spread of the virus, including genetic mutations, as it moved from China to Australia to Europe and the rest of the world, according to Newsweek.

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They mapped the genetic history of the infection from December to March and found three distinct, but closely related, variants – A, B, and C.

Type A is believed to be the closest variant to that which was found in bats and is thought to be the original human virus genome.

This variant was found in both Chinese and American patients, though mutated versions of this strain was reported in Australia and the United States.

While Australian authorities are struggling to find a cure for the original virus which developed from animals, they're also battling a mutation known as strain C.

Type A is the most prevalent in Australia, however Type C has also been recorded in Sydney, according to the experts.

Analysis of the strains showed type A - the original virus that jumped to humans from bats via pangolins - was not China's most common.

Instead, the pandemic's ground-zero was mainly hit by type B, which was in circulation as far back as Christmas Eve.

Type B was also the dominant strain across large parts of the United Kingdom and Europe.

According to Forster, type B was also the variant that was found in most cases of infection reported in Wuhan.

Research suggests that there was a ‘founder event’ for type B in Wuhan.

In biology, a founder event is when a new population is established from a small number of individuals drawn from a large ancestral population.

According to Dr Forster, up until January 17, nearly all of the coronavirus variants found in Wuhan were type B.

The researchers found that in Guangdong, a province about 500 miles from Wuhan, seven of the 11 samples found in patients were type A.

Type C was an offshoot of type B, mutating from the secondary strain and spreading to Europe and Australia via Singapore.

Scientists believe the virus - officially called SARS-CoV-2 - is constantly mutating to overcome immune system resistance in different populations.

The data gathered by Dr Forster and his team indicate that the coronavirus outbreak apparently started sometime 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,’ Forster 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.’

The academics' published work - which has been scrutinised by fellow scientists - only traced the samples of 160 patients across the world, including many of the first cases in Europe and the US.

Methods used to trace the prehistoric migration of ancient humans were adapted to track the spread of the SARS-CoV-2 virus, which causes COVID-19.

The team have now updated their analysis to include more than 1,000 COVID-19 cases up to the end of March to provide a clearer snapshot.

The smaller snapshot, published in the journal PNAS, initially suggested that type C was the most common in Europe.

Animal viruses can mutate or combine with other viruses to create new strains capable of being passed to people.

Scientists say the new coronavirus originated in bats and then passed to humans, possibly via an intermediary animal species.

The broad scientific consensus holds SARS-CoV-2, the virus’ official name, originated in bats.

Scientists suspect, but have not proven, that the new coronavirus passed to humans from bats via pangolins, a small ant-eating mammal whose scales are highly prized in traditional Chinese medicine.

Some of the earliest infections were found in people who had exposure to Wuhan’s seafood market, where bats, snakes, civets and other wildlife were sold.

China temporarily shut down all such markets in January, warning that eating wild animals posed a threat to public health and safety.

The first known coronavirus case was reported on November 17, when a 55-year-old from Hubei province near Wuhan was diagnosed with COVID-19.

Experts, however, still do not know for certain where and how the virus made the leap from animals to humans.