RIO DE JANEIRO/SAO PAULO (Reuters) - The coronavirus outbreak hammered Brazil on Wednesday, crushing local markets, infecting more members of the country’s political elite and prompting loud protests against President Jair Bolsonaro, whose son waded into a diplomatic spat with China.

Bolsonaro’s national security adviser, the mines and energy minister and the head of the Senate all tested positive for the virus on Wednesday, as the death toll rose to four dead with 428 people infected.

Bolsonaro has come under mounting criticism for his lax handling of the outbreak, which he initially labeled a “fantasy.” The virus’ spread represents a major threat for the far-right populist, who was already struggling to resuscitate the country’s weak economy.

On Wednesday night, Brazil erupted to the sound of banging pots and pans and shouts of “Bolsonaro out!” with housebound protesters expressing their anger toward the president. The protests took place in major Brazilian cities and even included projections of “Bolsonaro out!” onto the sides of buildings, according to social media videos.

Bolsonaro says he has twice tested negative for the coronavirus, but 14 people in his entourage to Florida 10 days ago have tested positive. The fallout from the trip, in which he met U.S. President Donald Trump, haunts him.

In a fresh headache late on Wednesday, his son Eduardo, a federal lawmaker who also traveled to meet Trump, sparked a diplomatic dust-up with China, Brazil’s top trade partner.

In a tweet, he likened China’s role in the coronavirus outbreak to that of the USSR during the Chernobyl nuclear disaster, alleging a cover-up. “It’s China’s fault and freedom is the answer,” he tweeted.

His comments, which echoed those of Trump, sparked an angry response from the Chinese embassy, which said he had contracted a “mental virus” while in the United States.

“Sadly, you are a person without any international vision or common sense,” it tweeted at him. “We suggest you don’t rush to become the U.S. spokesman in Brazil, or risk an ugly fall.”

With criticism mounting, the president held an afternoon news conference with ministers - all wearing masks - to announce emergency measures to contain the virus and buttress the economy, including assistance for poorer families and support for a struggling aviation industry.

Financial markets were rattled by the fast-spreading virus that causes the COVID-19 respiratory disease.

The benchmark Bovespa stock index closed 10% lower, bond yields spiked and Brazil’s currency hit an all-time low of 5.2 per dollar before central bank measures in foreign exchange and bond markets helped to pare losses.

After markets closed, the central bank cut its benchmark interest rate to an all-time low of 3.75% and pledged “to deploy its arsenal of monetary, exchange rate and financial stability policies to fight the current crisis.”

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In a fresh blow to many retail stocks, Sao Paulo Governor Joao Doria on Wednesday recommended the closure of shopping malls in the metro area of the country’s biggest city, while Sao Paulo city hall also ordered commercial establishments closed to the public from Friday until April 5, with some exceptions.

Airline association ABEAR said the sudden halt in travel was the worst crisis ever faced by Brazil’s aviation sector. Demand for domestic flights in the second half of March fell 50% and international bookings were 85% down, ABEAR said.

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BORDER CLOSING

Bolsonaro said Brazil was considering closing all its land borders, following a decree closing its border to Venezuelans, citing contagion risks and strains on the public health system.

The decree, published on Wednesday, does not apply to trucks shipping goods or cross-border humanitarian aid previously authorized by health officials. The 15-day ban on Venezuelans entering Brazil could be extended, it added.

In another restriction of border traffic, land transport regulator ANTT suspended for 60 days all international bus services.

Seven cities neighboring Sao Paulo, Brazil’s biggest metropolis, said they would begin reducing municipal transportation until a total shutdown from March 29 onward.

In a an almost empty lower chamber of Congress, lawmakers approved a presidential decree declaring a national emergency, which allows the government to waive fiscal targets and free up budget resources. The decree is expected to pass the Senate next week.

Senate President Davi Alcolumbre said on social media that had been diagnosed while Bolsonaro Mines and Energy Minister Bento Albuquerque, 61, had tested positive. So, too, has the president’s National Security Advisor Augusto Heleno, 72.