The new Covid variant was detected in Japan in four travellers arriving from Brazil.
A Covid variant that is believed to have emerged in the South East of England is fuelling a spike in transmissions and there are fears another variant could drive further infections - or even be resistant to Covid vaccines.
The South East variant of Covid is up to 70% more transmissible and is spreading in a "frustrating and alarming" manner, which prompted the government to put England into a six-week lockdown.
The South Africa strain shares one mutation with the UK strain called 501Y: a potentially crucial one on the bit of the virus’ “receptor binding domain” that might help it grab onto our cells and infect them.
Should we be worried about another new mutation?
All viruses mutate, some quicker and more efficiently than others. If the mutation gives an advantage to the virus, for example it is more transmissible as in the case of the South East and South Africa variants, and begins to infect more people, a new dominant variant may develop.
Mutations are more likely the more infections there are as the virus is under renewed pressure to evolve, as so many millions of people have now become infected.
Prof Ravi Gupta, Professor of Microbiology at the University of Cambridge, said: “The Brazilian variant1 has three key mutations in the spike receptor binding domain (RBD) that largely mirror some of the mutations we are worried about it in the South African variant, hence the concern. "
But, one glimmer of hope is that experts believe the vaccine would work against it.
Dr Gupta says: "The SARS-CoV-2 RBD is one of the main targets for our immune defences and also the region targeted by vaccines and changes within this region are therefore worrisome. Vaccines are still likely to be effective as a control measure if coverage rates are high and transmission is limited as far as possible.”
What did Boris Johnson say the UK's response should be?
Speaking to senior MPs at the Liaison Committee into the government's response to the coronavirus crisis, Mr Johnson said he was "concerned about the new Brazilian variant" and insisted extra measures were being put in place to prevent it being imported to the UK.
He said the government were looking into whether or not the Brazilian variant was immune resistant.
Home Affairs Committee chairwoman Yvette Cooper subjected the Prime Minister to intense questioning over border measures saying the nation could have “stronger quarantine and stronger checks like very many other countries do”.
What is the situation in Brazil?
Brazil passed 200,000 deaths from the pandemic earlier this week, the second highest total around the globe.
President Jair Bolsonaro has continually downplayed the severity of the disease, believing prolonged lockdowns and restrictions would inflict more damage than the virus.
This week saw huge crowds gathered across the country to celebrate the new year.