A team of experts from the World Health Organization arrived in Wuhan Thursday to probe the origins of the coronavirus more than a year after it emerged, although two members were barred from boarding a flight in Singapore after testing positive for virus antibodies.

The international team of 13 scientists landed for their much-delayed mission, met by Chinese officials in hazmat suits and given throat swabs on arrival, and were whisked to a hotel where they must complete a two-week quarantine before starting their work.

China had largely brought the virus under control after strict lockdowns, mass testing and travel restrictions, but recent weeks have seen numbers climbing again
China had largely brought the virus under control after strict lockdowns, mass testing and travel restrictions, but recent weeks have seen numbers climbing again AFP / NICOLAS ASFOURI

The virus was first detected in the central Chinese city of Wuhan in late 2019 and has since billowed out across the world killing nearly two million people so far, infecting tens of millions and eviscerating the global economy.

The WHO says establishing the pathway of the virus from animals to humans is essential to preventing future outbreaks.

But despite painstaking months of negotiations over their remit, the team was blocked from arriving last week -- a sign of the political sensitivity of a virus origin story muddied by recrimination between nations, conjecture and denials.

Health workers at Wuhan's international airport as a World Health Organization team arrives to investigate the origins of the Covid-19 pandemic
Health workers at Wuhan's international airport as a World Health Organization team arrives to investigate the origins of the Covid-19 pandemic AFP / NICOLAS ASFOURI

And the UN health body said Thursday that while most the team had arrived, two members were not allowed to board the flight from Singapore to Wuhan after testing positive for coronavirus antibodies -- the latest twist in a long journey to China for the experts.

The WHO said in a tweet that all members of the team had "multiple negative PCR and antibody tests for COVID-19 in their home countries prior to traveling."

The trip comes as China moves to snuff out fresh clusters of the virus.

The WHO team will have to quarantine for two weeks before beginning their investigations
The WHO team will have to quarantine for two weeks before beginning their investigations AFP / NICOLAS ASFOURI

More than 20 million people are under lockdown in the north of China and one province has declared an emergency, as the country reported its first death from Covid-19 in eight months.

China had largely brought the pandemic under control through strict lockdowns and mass testing, hailing its economic rebound as an indication of strong leadership by the Communist authorities.

But another 138 infections were reported by the National Health Commission on Thursday -- the highest single-day tally since March last year.

Covid-19 origins: a timeline of dispute
Covid-19 origins: a timeline of dispute AFP / John SAEKI

Clusters are still small compared with many countries contending with rampant infections and record numbers of deaths.

But the first Chinese virus fatality in several months -- a woman with underlying conditions in northern Hebei province -- seeded alarm across China.

The hashtag "New virus death in Hebei" quickly ratcheted up 270 million views on Chinese social media platform Weibo on Thursday.

A team of ten scientists will investigate the origins of the new virus in a politically fraught mission that comes more than a year after the pandemic began and after accusations Beijing has tried to thwart the project. Finding the origins of the SARS-Cov
A team of ten scientists will investigate the origins of the new virus in a politically fraught mission that comes more than a year after the pandemic began and after accusations Beijing has tried to thwart the project. Finding the origins of the SARS-Covid-2 'could be a very long journey', says Peter Ben Embarek, head of the international WHO mission to China. AFPTV / Danni ZHU

"I haven't seen the words 'virus death' in so long, it's a bit shocking! I hope the epidemic can pass soon," one user wrote.

The last death reported in mainland China was in May last year, with the official death toll now standing at 4,635.

Beijing is anxious to stamp out local clusters ahead of next month's Lunar New Year festival when hundreds of millions of people will be on the move across the country.

As infections have spread, northeastern Heilongjiang declared an "emergency state" on Wednesday, telling its 37.5 million residents not to leave the province unless absolutely necessary.

China is braced for the scrutiny the expert team of WHO scientists will bring to its virus narrative.

Beijing has drip-fed the idea that the pandemic started outside of its borders, preferring to focus on its relatively swift control of the public health crisis.

The WHO have been at pains to cut the political baggage attached to their mission.

Peter Ben Embarek, team lead, said the group would start with a mandatory hotel quarantine.

"And then after the two weeks, we would be able to move around and meet our Chinese counterparts in person and go to the different sites that we will want to visit," he said.

He warned it "could be a very long journey before we get a full understanding of what happened".

"I don't think we will have clear answers after this initial mission, but we will be on the way," Embarek added.

"The idea is to advance a number of studies that were already designed and decided upon some months ago to get us a better understanding of what happened," he said.

Coronavirus China