Australia to lock down 300,000 in Melbourne suburbs after coronavirus spike

Beijing, May 24: The Chinese virology institute in the city where COVID-19 first emerged has three live strains of bat coronavirus on-site, but none match the new contagion wreaking chaos across the world, its director has said.

Scientists think COVID-19 -- which first emerged in Wuhan and has killed some 340,000 people worldwide -- originated in bats and could have been transmitted to people via another mammal.

But the director of the Wuhan Institute of Virology told state broadcaster CGTN that claims made by US President Donald Trump and others that the virus could have leaked from the facility were "pure fabrication".

"Now we have three strains of live viruses... But their highest similarity to SARS-CoV-2 only reaches 79.8 percent," she said, referring to the coronavirus strain that causes COVID-19.

US demands immediate start to WHO review

The United States called on the World Health Organisation on Friday to begin working immediately on investigating the source of the novel coronavirus, as well as its handling of the response to the pandemic.

One of their research teams, led by Professor Shi Zhengli, has been researching bat coronaviruses since 2004 and focused on the "source tracing of SARS", the strain behind another virus outbreak nearly two decades ago.

"We know that the whole genome of SARS-CoV-2 is only 80 percent similar to that of SARS. It's an obvious difference," she said.

"So, in Professor Shi's past research, they didn't pay attention to such viruses which are less similar to the SARS virus."

Conspiracy rumours that the biosafety lab was involved in the outbreak swirled online for months before Trump and US Secretary of State Mike Pompeo brought the theory into the mainstream by claiming that there is evidence the pathogen came from the institute.

The lab has said it received samples of the then-unknown virus on December 30, determined the viral genome sequence on January 2 and submitted information on the pathogen to the WHO on January 11.

Wang said in the interview that before it received samples in December, their team had never "encountered, researched or kept the virus."

"In fact, like everyone else, we didn't even know the virus existed," she said. "How could it have leaked from our lab when we never had it?"

The World Health Organization said Washington had offered no evidence to support the "speculative" claims.

In an interview with Scientific American, Shi said the SARS-CoV-2 genome sequence did not match any of the bat coronaviruses her laboratory had previously collected and studied.

London, May 20: The current physical distancing guidelines of 6 feet may be insufficient to prevent COVID-19 transmission, according to a study which says a mild cough in low wind speeds can propel saliva droplets by as much as 18 feet.

Researchers, including those from the University of Nicosia in Cyprus, said a good baseline for studying the airborne transmission of viruses, like the one behind the COVID-19 pandemic, is a deeper understanding of how particles travel through the air when people cough.

In the study, published in the journal Physics of Fluids, they said even with a slight breeze of about four kilometres per hour (kph), saliva travels 18 feet in 5 seconds.

"The droplet cloud will affect both adults and children of different heights," said study co-author Dimitris Drikakis from the University of Nicosia.

According to the scientists, shorter adults and children could be at higher risk if they are located within the trajectory of the saliva droplets.

They said saliva is a complex fluid, which travels suspended in a bulk of surrounding air released by a cough, adding that many factors affect how saliva droplets travel in the air.

These factors, the study noted, include the size and number of droplets, how they interact with one another and the surrounding air as they disperse and evaporate, how heat and mass are transferred, and the humidity and temperature of the surrounding air.

In the study, the scientists created a computer simulation to examine the state of every saliva droplet moving through the air in front of a coughing person.

The model considered the effects of humidity, dispersion force, interactions of molecules of saliva and air, and how the droplets change from liquid to vapour and evaporate, along with a grid representing the space in front of a coughing person.

Each grid, the scientists said, holds information about variables like pressure, fluid velocity, temperature, droplet mass, and droplet position.

The study analysed the fates of nearly 1,008 simulated saliva droplets, and solved as many as 3.7 million equations.

"The purpose of the mathematical modelling and simulation is to take into account all the real coupling or interaction mechanisms that may take place between the main bulk fluid flow and the saliva droplets, and between the saliva droplets themselves," explained Talib Dbouk, another co-author of the study.

However, the researchers added that further studies are needed to determine the effect of ground surface temperature on the behaviour of saliva in air.

They also believe that indoor environments, especially ones with air conditioning, may significantly affect the particle movement through air.

This work is important since it concerns safety distance guidelines, and advances the understanding of the transmission of airborne diseases, Drikakis said.

New York, May 8: An Indian-American father and daughter, both doctors in New Jersey, have died due to the COVID-19, with Governor Phil Murphy describing their demise as “particularly tough" and hailed them for dedicating their lives for others.

Satyender Dev Khanna, 78, was a surgeon who served both on staff and as the head of the surgical departments for multiple hospitals across New Jersey for decades.

Priya Khanna, 43, was a double board-certified in both internal medicine and nephrology. She was Chief of Residents at Union Hospital, now part of RWJ Barnabas Health.

"Dr Satyender Dev Khanna and Dr Priya Khanna were father and daughter. They both dedicated their lives to helping others. This is a family dedicated to health and medicine. Our words cannot amply express our condolences," New Jersey Governor Murphy tweeted on Thursday.

“Both dedicated their lives to helping others and we lost both of them to COVID-19,” Murphy said during a press conference on Thursday, saying their demise is a "particularly tough one.”

Satyender passed away at the Clara Maass Medical Center where he had worked for more than 35 years.

Murphy described him as a "pioneering doctor” who was one of the first surgeons to perform laparoscopic surgery in the state. He is being remembered by colleagues as a “gentle and caring physician."

“And for a doctor, I'm not one, but I would bet, I don't think there could be a more fitting way to be remembered, or a nurse or a healthcare worker of any kind,” Murphy said, adding that the doctor had a passion for bicycling, and he often found peace from the hustle of the hospital in biking along the Jersey Shore.

Priya did all of her medical training in New Jersey and then did her fellowship in nephrology in South Jersey with the Cooper Health System. Like her father, she too worked at Clara Maass, where she died.

She was also Medical Director at two dialysis centres in Essex County and “took pride” in teaching the next generation of doctors, Murphy said, adding that the ICU physician who cared for Priya Khanna was trained and taught by her as well.

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“Priya will be remembered as a caring and selfless person who put others first. And even while in the hospital, fighting her own battle, she continued to check up on her mom and dad and her family,” Murphy said.

“This is a family, by the way, dedicated to health and medicine,” he said.

The governor spoke with Satyender's wife Komlish Khanna, who is a paediatrician. The couple has two more daughters - Sugandha Khanna, an emergency medicine physician and Anisha Khanna, a paediatrician.

“Unbelievable. Our words cannot amply express our condolences nor, I am sure, can they express the pain that the Khanna family is feeling. But I hope that the fact that our entire state mourns with them is some small comfort. And we mourn everyone we have lost. We commit in their memory to saving as many lives as we can,” Murphy said.