China has taken drastic measures in an attempt to disinfect the country amid the coronavirus outbreak.

Researchers say they may have pinpointed the source of the deadly coronavirus as the death toll soars past 1600.

Scientists from South China University of Technology in Guangzhou wrote and published a paper speculating that a centre for disease control near a Wuhan seafood market may be ground zero for the virus.

Botao Xiao and Lei Xiao wrote that the Wuhan Centre for Disease Control and Prevention was the possible source because it “hosted animals in laboratories for research purposes”, including bats, and was “within 280 metres of the Huanan Seafood Market where a number of early infections were reported”.

In the paper, titled The possible origins of 2019-nCoV coronavirus, researchers explained that “41 people in Wuhan were found to have the acute respiratory syndrome and 27 of them had contact with Huanan Seafood Market”.

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They wrote: “According to municipal reports and the testimonies of 31 residents and 28 visitors, the bat was never a food source in the city, and no bat was traded in the market.”

The research facility was also adjacent to the Union Hospital where the first group of doctors were infected.

On one occasion, a worker at the WCDCP was “once attacked by bats and the blood of a bat (was) shot on his skin”, the researchers said.

“He knew the extreme danger of the infection so he quarantined himself for 14 days,” the scientists wrote.

“In another accident, he quarantined himself again because bats (urinated) on him.”

Workers at the facility routinely extracted tissue samples from the bats, but it was not the only facility in the area doing so.

The second laboratory, the Wuhan Institute of Virology, Chinese Academy of Sciences, was 12km from the seafood market.

The scientists wrote that the institute reported that Chinese horseshoe bats were natural reservoirs for the SARS virus that caused the 2002 pandemic and that “somebody was entangled with the evolution of 2019-nCoV coronavirus”.

The seafood market was closed down as part of quarantine procedures when the viral outbreak began, but authorities have still not determined how it started.

China’s Global Times reports a research fellow from the Wuhan Institute of Virology said on Saturday: “I can promise that not a single person was infected at our institute, including graduate students. We have zero infection cases.”

The death toll climbed to 1665 in mainland China over the weekend after 142 further recorded deaths, according to the Chinese authorities’ daily report.

However, in central Hubei province, the epicentre of the virus, the number of new cases slowed for a third straight day to 1843. More than 68,500 people have been infected across the country.

Elsewhere, the fifth death was recorded outside mainland China when Taiwan reported its first victim.

Previous victims were from the Philippines, Hong Kong, Japan and France. The Taiwanese victim is a 61-year-old unlicensed taxi driver, whose “main clients were people who had been to China, Hong Kong and Macao”, Health and Welfare Minister Chen Shih-chung said.

In Japan, the number of new infections has continued to rise, with six new cases reported on Sunday, most of them in Tokyo.

Forty Americans are also among hundreds with the new coronavirus on a cruise ship quarantined off Japan, a US official said on Sunday, after other Americans on-board left for chartered flights home.

The Diamond Princess was placed in a 14-day quarantine in early February after a former passenger tested positive for the COVID-19 virus.

A Melbourne woman on-board also tested positive.

Several governments have announced plans to remove their citizens from the ship.

Australians who had visited Wuhan and were quarantined on Christmas Island will begin arriving back on mainland Australia after no reported cases of the virus were discovered.

With AFP