Japan has detected a third mutant strain of coronavirus that is similar to the highly infectious variants spreading across the UK and South Africa.

The strain was found in four passengers arriving from Brazil who were quarantined at Haneda Airport in Tokyo when they tested positive, Nikkei Asia reports.

Three of the group developed symptoms including struggling to breath, a fever and a sore throat, while one man in his 40s arrived on January 2 without any symptoms.

But he was later rushed to hospital with difficulties breathing, Bloomberg reports. Japan’s National Institute of Infectious Diseases (NIID) confirmed the mutant strain and it was reported to the World Health Organisation (WHO).

The country has seen a spike in coronavirus cases, with more than 6,000 new cases a day for the last four days, according to John Hopkins Coronavirus Resource Center. Since the pandemic began Japan has recorded 290,270 cases and 3,870 deaths.

On Friday, the country’s state of emergency came into effect for Tokyo and the surrounding areas. Bars and restaurants will be forced to close at 8pm for a month-long period which can be extended.

This is the most recently discovered mutant strain of the virus after the UK and South Africa uncovered their own highly infectious variants.

The UK’s variant, found in early December, is thought to be the reason behind the latest deadly wave, with record high daily deaths and hospital admissions.

Last Friday saw the highest daily death toll since the pandemic began, with 1,325 fatalities recorded nationwide. About two weeks after the UK found its mutant strain South Africa revealed an even more infectious variant.

The country went into its second hard lockdown on December 28, banning the sale of alcohol so hospital beds are kept free from alcohol-related trauma cases.