Brazilian President Jair Bolsonaro, who has consistently downplayed the risks of coronavirus, announced Tuesday he has tested positive, as the United States -- the nation hardest hit by the pandemic -- formally launched its withdrawal from the World Health Organization (WHO).
The UN health agency meanwhile acknowledged that there was "emerging evidence" of airborne transmission of COVID-19, which has infected nearly 11.7 million people around the globe and caused more than 539,000 deaths.
Bolsonaro, who said he had experienced only mild symptoms, has ignored containment measures such as social distancing, despite Brazil being the second-worst hit country, with more than 66,000 dead.
The far-right leader, who at 65 is in the highest-risk age category, insisted he was feeling "perfectly well" and took off his face mask during a TV interview announcing his test results.
He repeated his mantra that the "collateral effects" of the virus should not be worse than the illness itself.
Since the beginning of the virus outbreak, Bolsonaro has minimized the risks of what he initially called "a little flu" while resisting wearing a mask in public.
Brazil is a large reason why Latin America and the Caribbean has now surpassed three million cases, according to an AFP tally.
The region has seen nearly 140,000 deaths, nearly half of them in Brazil.
'Chaotic and incoherent'
In Washington, a senior US official said the United States had informed UN Secretary General Antonio Guterres of its intention to leave the WHO, effective July 6, 2021.
President Donald Trump has been critical of the WHO's pandemic response, accusing it of bias toward China and ignoring early signs of human-to-human transmission of the deadly virus.
The United States is the largest financial contributor to the WHO -- which leads the fight on global maladies from polio and measles to mental health -- providing $400 million annually.
Joe Biden, the presumptive Democratic presidential nominee, said Tuesday he would immediately reverse the decision and keep the US in the WHO if he defeats Trump in November.
Senator Robert Menendez, the top Democrat on the Foreign Relations Committee, criticized the Trump administration's move.
"To call Trump's response to COVID chaotic and incoherent doesn't do it justice," Menendez said.
"This won't protect American lives or interests -- it leaves Americans sick & America alone."
'Unsustainably high numbers'
Critics say Trump is seeking to deflect criticism from his own handling of the pandemic, which has killed nearly 131,000 people in the United States, by far the highest death toll of any nation.
Officials have said hospitals in some parts of the country are in danger of being overwhelmed, with many states hit particularly hard after they eased virus restrictions.
Texas -- one of the new US hotspots -- on Tuesday registered a new daily case total of 10,028, making it the third state after New York and Florida to hit the grim milestone.
Top infectious disease expert Anthony Fauci has warned the country is still "knee-deep" in the first coronavirus wave.
But Trump pounced on that comment Tuesday, saying the United States was "in a good place" and adding: "I disagree with him."
Experts are still struggling to understand COVID-19, and the WHO said it was open to new research after scientists lobbied for it to stress that the virus can spread through the air farther and for longer than initially believed.
There have been explosions of infections across the world, including Iran, which announced 200 new deaths on Tuesday.
Australia on Tuesday ordered five million people locked down in Melbourne, its second-biggest city, to combat a surge in cases.
"We can't pretend" the crisis is over, said Daniel Andrews, premier of Victoria state.
The restrictions in the Melbourne area will last at least six weeks, while Victoria state will be effectively sealed off from the rest of the country.
Cases are also surging in India and four new coronavirus field hospitals were opened on Tuesday in the financial capital Mumbai as the nationwide death toll jumped past 20,000.
Italy's health minister ordered a one-week suspension of flights to Rome from Bangladesh on Tuesday, after 21 passengers arriving from Dhaka tested positive, adding to the number of cases within the Bangladeshi community in the Lazio region surrounding Rome.
Lazio's top health official Alessio D'Amato called it a "veritable viral 'bomb' that we've defused."
Meanwhile, the head of the prestigious Royal Society science journal said Tuesday that people who refuse to wear face masks during the pandemic should be stigmatized in the same manner as drink-drivers.
"If all of us wear one, we protect each other and thereby ourselves, reducing transmission," wrote Venki Ramakrishnan.