In a recent study about coronavirus, experts from Cambridge University were able to map the genetic history of COVID-19 from December, when the spread was first recorded, to March, discovering that the virus has three distinct strains, all of which are closely related to each other.
Three Distinct Coronavirus Strains
According to the Daily Mail, analysis of the genetic history of SARS-CoV-2 or the novel coronavirus shows that Type A, which is the strain that came from bats and jumped to humans from pangolins, was not common in China--the origin of the outbreak.
Instead, Type B, which is derived from Type A coronavirus via two mutations, is more prevalent in the country, specifically in ground zero: Wuhan.
Nevertheless, the original variation has been found in over 400,000 COVID-19 cases in the United States and Australia.
Two-thirds of the samples acquired from the U.S. showed that they have a Type A novel coronavirus and that the infected patients did not come from New York, which is considered an epicenter of the COVID-19 infection in the U.S.
Instead, most of the patients came from the West Coast.
Type B Coronavirus is More Common in Europe
Meanwhile, the Type B strain of the coronavirus is more prevalent in Europe, specifically in the United Kingdom, with three-quarters of the samples from the country testing positive for the strain.
Countries like Belgium, the Netherlands, Switzerland, France, and Germany also have dominant cases of Type B coronavirus strain.
On the other hand, Type C coronavirus strain is also common in some places in Europe as well as in Asia, specifically in Singapore. This strain is the "daughter" of Type B and is just one mutation different from it.
The study, which was published in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS), drew out an oddity: Type A was more common in the U.S., but not in China.
Nevertheless, both strains have already been present in January when the U.S. has recorded its first COVID-19 case, meaning the coronavirus strain did not arrive earlier or was never detected in the first place.
Dr. Peter Forster and his team believe that their study is too small to draw any conclusion, seeing as they only tested 160 samples, which included the first cases in the U.S. and Europe.
With that, the study has drawn some criticisms from their peers.
Coronavirus is Constantly Mutating
However, the team is updating the analysis and including 1,000 COVID-19 samples for a clearer interpretation of the coronavirus spread, but it hasn't been peer-reviewed yet.
Another study from the Icahn School of Medicine at Mount Sinai NYU concluded that travelers from Europe brought the virus to New York, but the coronavirus strand that appeared in Washington state was from China, which echoed the study of Dr. Forster and his team.
Dr. Forster admitted that they are still scratching their heads with how Type B "pushed aside" the original coronavirus strain to become more prevalent in China, yet he believes it will be answered "one day."
Experts also believe that the coronavirus is continuously mutating to overcome the immune system resistance of different populations.