Coronavirus spread from people without symptoms is rare, says WHO

May 20: The novel coronavirus is behaving differently in patients in northeast China who have contracted it recently compared with early cases, indicating it is changing as it spreads, a prominent doctor said.

China, which has largely brought the virus under control, has found new clusters of infections in the northeastern border provinces of Jilin and Heilongjiang in recent weeks, raising concern about a second wave.

Qiu Haibo, an expert in critical care medicine who is part of a National Health Commission expert group, said the incubation period of the virus in patients in the northeast was longer than that of patients in Wuhan, the central city, where the virus emerged late last year.

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"This causes a problem, as they don't have any symptoms. So when they gather with their families they don't care about this issue and we see family cluster infections," Qiu told state broadcaster CCTV in a programme broadcast late on Tuesday.

Patients in the northeastern clusters were also carrying the virus for longer than earlier cases in Wuhan, and they were taking longer to recover, as defined by a negative nucleic acid test, he said.

Patients in the northeast also rarely exhibited fever and tended to suffer damage to the lungs rather than across multiple organs, he said.

He said the virus found in the northeastern clusters was probably imported from abroad, which could account for the differences.

He did not say where he though they might have come from but both Jilin and Heilongjiang border Russia.

China reported five new coronavirus cases on Wednesday, down from six a day earlier.

Four of the new cases were local transmissions and one was imported by a traveller coming from abroad, the commission said in a statement, compared with three imported cases reported the previous day.

China's total number of coronavirus infections stands at 82,965, while the death toll 4,634. 

Jan 23: Hundreds of Central Americans trying to reach the United States were stuck at the Mexico-Guatemala border on Wednesday after the Mexican government beefed up security to meet US demands to contain migrant flows.

Under sustained pressure from President Donald Trump, Mexico's government has adopted tougher measures to reduce the number of people heading towards the U.S. border.

Migrants in Tecun Uman, on the Guatemalan side of the border, were taken by surprise.

"We thought we'd be allowed through just like with the October caravan when they reached Tijuana," said Honduran migrant Ritzy Anabel, who did not give her surname.

"People from Mexico and Guatemala treated them well. But now it's changed because Mexicans don't want (us) to enter."

Many Central Americans migrants heading north are fleeing economic hardship and violence at home. A large caravan of migrants crossed into Mexico and went north in October 2018. Migrants crossing into Mexico earlier this week faced tear gas from security forces, who delivered a firmer response than in previous mass movements at the border.

Even so, about 1,000 migrants, most of them from Honduras, managed to reach Mexican soil on Tuesday. Mexican Foreign Minister Marcelo Ebrard said several hundred of the new arrivals were immediately deported on planes and buses.

On Wednesday, Mexican authorities said that 460 Honduran migrants were deported throughout the day. Other migrants from the group, including families traveling with children, were pondering their next moves.

Honduran Carlos Amador said that while some of his compatriots were returning home, others were hoping for positive news.

Trump has repeatedly threatened to punish Mexico and Central American countries if they fail to clamp down on the migrant flows. That has resulted in a series of agreements aimed at delivering on Trump's campaign promises to curb immigration.

Department of Homeland Security Acting Secretary Chad Wolf called the measures put in place by the Mexican National Guard "effective", adding that dozens of his personnel was on the ground in Central America assisting local immigration and security officials. Trump tweeted: "Sorry, if you come you will be immediately sent back!"