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Toronto, May 7: Scientists have uncovered how bats can carry the MERS coronavirus without getting sick, shedding light on what triggers coronaviruses, including the one behind the COVID-19 pandemic, to jump to humans.

According to the study, published in the journal Scientific Reports, coronaviruses like the Middle East respiratory syndrome (MERS) virus, and the COVID19-causing SARS-CoV-2 virus, are thought to have originated in bats.

While these viruses can cause serious, and often fatal disease in people, bats seem unharmed, the researchers, including those from the University of Saskatchewan (USask) in Canada, said.

"The bats don't get rid of the virus and yet don't get sick. We wanted to understand why the MERS virus doesn't shut down the bat immune responses as it does in humans," said USask microbiologist Vikram Misra.

In the study, the scientists demonstrated that cells from an insect-eating brown bat can be persistently infected with MERS coronavirus for months, due to important adaptations from both the bat and the virus working together.

"Instead of killing bat cells as the virus does with human cells, the MERS coronavirus enters a long-term relationship with the host, maintained by the bat's unique 'super' immune system," said Misra, one of the study's co-authors.

"SARS-CoV-2 is thought to operate in the same way," he added.

Stresses on bats, such as wet markets, other diseases, and habitat loss, may have a role in coronavirus spilling over to other species, the study noted.

"When a bat experiences stress to their immune system, it disrupts this immune system-virus balance and allows the virus to multiply," Misra said.

The scientists, involved in the study, had earlier developed a potential treatment for MERS-CoV, and are currently working towards a vaccine against COVID-19.

While camels are the known intermediate hosts of MERS-CoV, they said bats are suspected to be the ancestral host.

There is no vaccine for either SARS-CoV-2 or MERS, the researchers noted.

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"We see that the MERS coronavirus can very quickly adapt itself to a particular niche, and although we do not completely understand what is going on, this demonstrates how coronaviruses are able to jump from species to species so effortlessly," said USask scientist Darryl Falzarano, who co-led the study.

According to Misra, coronaviruses rapidly adapt to the species they infect, but little is known on the molecular interactions of these viruses with their natural bat hosts.

An earlier study had shown that bat coronaviruses can persist in their natural bat host for at least four months of hibernation.

When exposed to the MERS virus, the researchers said, bat cells adapt, not by producing inflammation-causing proteins that are hallmarks of getting sick, but instead by maintaining a natural antiviral response.

On the contrary, they said this function shuts down in other species, including humans.

The MERS virus, the researchers said, also adapts to the bat host cells by very rapidly mutating one specific gene.

These adaptations, according to the study, result in the virus remaining long-term in the bat, but being rendered harmless until something like a disease, or other stressors, upsets this balance.

In future experiments, the scientists hope to understand how the bat-borne MERS virus adapts to infection and replication in human cells.

"This information may be critical for predicting the next bat virus that will cause a pandemic," Misra said.

Melbourne, Jul 24: Home-made cloth face masks may need a minimum of two layers, and preferably three, to prevent the dispersal of viral droplets associated with Covid-19, according to a study.

Researchers, including those from the University of New South Wales in Australia, noted that viral droplets are generated by those infected with the novel coronavirus when they cough, sneeze, or speak.

As face masks have been proven to protect healthy people from inhaling infectious droplets as well as reducing the spread from those who are already infected, several types of material have been suggested for these, but based on little or no evidence of how well they work, the scientists said.

In the current study, published in the journal Thorax, the researchers compared the effectiveness of single and double-layer cloth face coverings with a surgical face mask (Bao Thach) at reducing droplet spread.

They said the single layer covering was made from a folded piece of cotton T shirt and hair ties, and the double layer covering was made using the sew method described by the US Centers for Disease Control and Prevention (CDC).

The scientists used a tailored LED lighting system and a high-speed camera to film the dispersal of airborne droplets produced by a healthy person with no respiratory infection, during speaking, coughing, and sneezing while wearing each type of mask.

Their analysis showed that the surgical face mask was the most effective at reducing airborne droplet dispersal, although even a single layer cloth face covering reduced the droplet spread from speaking.

But the study noted that a double layer covering was better than a single layer in reducing the droplet spread from coughing and sneezing.

According to the researchers, the effectiveness of cloth face masks is dependent on the number of layers of the covering, the type of material used, design, fit as well as the frequency of washing.

Based on their observations, they said a home made cloth mask with at least two layers is preferable to a single layer mask.

"Guidelines on home-made cloth masks should stipulate multiple layers," the scientists said, adding that there is a need for more research to inform safer cloth mask design.

Amid the rapid spread of the novel coronavirus (COVID-19), which has infected 73 people in India and killed more than 4,500 individuals globally, doctors have advised that in addition to regularly washing hands, one should also disinfect their smartphone every 90 minutes with alcohol-based hand sanitizer.

Ravi Shekhar Jha, Head of Department at Fortis Escorts Hospital in Faridabad said the best method to disinfect your smartphone is to use regular doctor spirit or the alcohol-based hand sanitizer at least every 90 minutes.

"Avoid touching your eyes, mouth, or nose. The best option is to use a phone cover or a Bluetooth device and try to touch your phone as less as possible. We would also recommend cleaning your phone at least twice a day," Jha told IANS.

According to research, published in 2018 by Insurance2Go, a gadget insurance provider, revealed that smartphone screens have three times more germs than a toilet seat.

One in 20 smartphone users was found to clean their phones less than every six months, said the study.

"In the time of fear of coronavirus, smartphones should also be disinfected with alcohol-based sanitizer rub. Pour few drops of sanitizer on a tiny clean cotton pad and rub it safely on your entire phone," said Jyoti Mutta, Senior Consultant, Microbiology, Sri Balaji Action Medical Institute in New Delhi.

"You can repeat this process every evening coming back home after an entire day out at work and once in the morning before going out," Mutta added.

"Maintain basic cleanliness, and try to avoid using other's phones especially if suffering from respiratory illness or flu-like symptoms as there is no other way to disinfect these regular gadgets," she stressed.

Another study from the University of Surrey in the UK, also found that the home button on your smartphone may be harbouring millions of bacteria - some even harmful.

The World Health Organisation (WHO) declared the novel coronavirus as a global pandemic on Wednesday. The death toll of COVID-19 has crossed the 4,500 marks and confirmed cases globally have touched one lakh as per the reports.

According to Suranjeet Chatterjee, Senior Consultant in Internal Medicine Department of Indraprastha Apollo Hospitals in New Delhi, "We should frequently wash our hands, cover our coughs and it is important to adapt to other good hygiene habits that are most important in such a situation."

"Coronavirus and other germs can live on surfaces like glass, metal or plastics and phones are bacteria-ridden. It is necessary that we sanitize our hands frequently and make sure that our hands are clean all the time," Chatterjee told IANS.

"The emphasis should be laid on sanitising our hands rather than sanitizing the phone - once in a while the phone can be sanitized under the guidance of the makers of the phone," Chatterjee stressed.

According to the global health agency, the most effective way to protect yourself against coronavirus is by frequently cleaning of your hands with alcohol-based hand rub or washing them with soap and water.

The WHO's report showed the virus infects people of all ages, among which older people and those with underlying medical conditions are at a higher risk of getting infected.

People should eat only well-cooked food, avoid spitting in public, and avoid close contact, the WHO said, adding that it is important for people to seek medical care at the earliest if they become sick.