Saturday, March 28, 2020

Zoonotic diseases are nothing new but pose a severe threat

Swallow cave, near Jianshui, Honghe prefecture in Yunnan province, China, some 60 km from the provincial capital Kunming.

It is known for the hundreds of swallows that make the cave their home, hundreds of which can be seen flying around in Spring.

The cave, like many across southern China, is also home to bats which are known to harbour many viruses including coronaviruses.

From bats to humans

One virologist and researcher, Shi Zhengli, who works out of the Wuhan Institute of Virology (WIV), which is part of the Chinese Academy of Sciences, was one of a team of scientists who, in 2005, showed that the SARS pathogen was a bat virus that had spilled over into people.

In a 2017 paper, they set out how, after nearly five years of collecting faecal samples from bats in the Yanzi and Shitou caves in Yunnan province, they had found coronaviruses in multiple individuals of four different species of bats, including one called the intermediate horseshoe bat, because of the half-oval flap of skin protruding like a saucer around its nostrils. The genome of that virus, Shi and her colleagues announced, is 96% identical to the Wuhan virus that has recently been found in humans. And those two constitute a pair distinct from all other known coronaviruses, including the one that causes SARS. In this sense, nCoV-2019 or COVID-19 is novel — and possibly even more dangerous to humans than the other coronaviruses.

Red flags

Peter Daszak, the president of EcoHealth Alliance, a private research organization based in New York that focuses on the connections between human and wildlife health, is one of Shi's longtime partners. "We've been raising the flag on these viruses for 15 years ever since SARS," he told the NYT. Daszak was a co-author of a 2005 bats-and-SARS study, and again of the 2017 paper about the multiple SARS-like coronaviruses in the Yunnan caves.

Before SARS, the world had little inkling of coronaviruses — named because, seen under a microscope, their spiky surface resembles a crown — says Linfa Wang, who directs the emerging infectious diseases program at Singapore's Duke-NUS Medical School.

Coronaviruses were mostly known for causing common colds. "The SARS outbreak was a game changer," says Wang, whose work on bat-borne coronaviruses got a swift mention in the 2011 Hollywood movie Contagion. It was the first time a deadly coronavirus with pandemic potential emerged. The discovery helped to jump-start a global search for animal viruses that could find their way into humans.


It is widely believed that the nCoV-2019 or COVID-19 coronavirus probably made the jump to humans via an intermediary host - a process known as zoonosis - possibly a pangolin, whose scales are widely used in Traditional Chinese Medicine despite the trade and trafficking of the animal being illegal. But whilst evidence points to the pangolin as the most likely intermediate host for the new coronavirus, additional intermediate hosts could be possible, researchers say.

The trade in pangolins across China, Vietnam and other parts of south-east Asia has driven the only scaled mammal to virtual extinction [YouTube].

The pangolin is highly prized for its scales which some say can cure cancer, though there is no scientific evidence for the medicinal claims. "Roast pangolin scales are used, combined with other traditional material, to promote blood circulation, dispel clotting or swelling, and it is used more often on women who want to stimulate lactation after giving birth or on people who suffer from cancer," says Sun Xiuqing, a senior traditional Chinese medicine doctor at Jingshun hospital in Beijing. The creature is also found on the menus of restaurants, despite its illegality.

Blame game

Of course it's easy to point a finger at another culture for their unusual diet and exploitation of animals, especially when such practices might appear to be the cause of a global pandemic.

But there are few countries in the world that are guilt free when it comes to eating exotic or wild animals or of exploiting natural resources and animals. 

There have been several viruses that have caused great concern in recent years. And many have made the jump from animal to human.

Indeed the list of such viruses emerging into humans sounds like a grim drumbeat: Machupo [from mice and rats], Bolivia, 1961; Marburg [from grivet monkeys], Germany, 1967; Ebola [possibly from bats through pigs to humans], Zaire and Sudan, 1976; H.I.V. [believed to have originated in non-human primates in West-central Africa and initially spread through bushmeat traditions], recognized in New York and California, 1981; a form of Hanta (now known as Sin Nombre) [from the deer mouse], southwestern United States, 1993; Hendra [likely fruit bats and flying foxes to horses and humans], Australia, 1994; bird flu [from birds, and particularly poultry - H5N1 emerged from the original strain], Hong Kong, 1997; Nipah [from fruit bats infecting humans via contaminated fruit and infected pigs], Malaysia, 1998; West Nile [from birds to humans via mosquito bites], New York, 1999; SARS [horseshoe bats via civets to humans], China, 2002-3; Swine Flu H1N1 and variants, North America [from pigs to humans]; MERS [from bats and believed to have spread to humans via camels], Saudi Arabia, 2012; Ebola again, West Africa, 2014. 

Not the first nor the last pandemic

It is just over a century that the last major pandemic struck, that of the so-called Spanish Flu [though it likely did not originate there], a strain of the H1N1 virus or swine flu which infected at least 500 million people, or a quarter of the global population and killed at least 50 million.

Given the dubious practices of animal husbandry and close interaction with animals, it was only a matter of time before a particularly virulent virus made the jump from animals.

COVID-19 or nCoV-2019, like all coronaviruses, raises particular concerns for scientists however. Coronaviruses can mutate, something that can make fighting off the spread particularly difficult.

The global health emergency which everyone is facing is only the first battle humans face. After the pandemic subsides one will have to make some drastic changes as to how we live; how closely we live with animals, how we exploit the animal population and how we look after the planet in general. If we don't, next time the bite from 'mother nature' could be much harder.

Sources: NYT / Scientific American / PlosPathogens / Institute of British Geographers / WHO / Science Direct / National Center for Biotechnology Information / China Dialogue / BBCStraits Times / SCMPCenter for Infectious Disease Research and Policy / National Center for Biotechnology Information / PlosPathogens / Guardian

tvnewswatch, London, UK

Thursday, March 05, 2020

Beijing far from normal as COVID-19 restrictions remain

China has recently claimed that businesses and industry were returning to a state of normality. However, while the numbers of new cases of COVID-19 are seemingly reducing in China, the situation is far from normal. Indeed even outside the main hotspots, such as Wuhan in Hubei province, where the first cases of the coronavirus were detected, lockdowns remain in force along with strict regulations.

Even in the nation's capital, Beijing, whilst life is returning to the streets, which have been empty for weeks, for the most part the city remains a ghost town.

"Residential areas are still under closed-off management," one Beijing resident tells tvnewswatch, "There is only entry with a permit, and body temperatures are taken."

Indeed many people prefer to stay at home if they have no need to go out. Today was a little different. Blue skies and slightly warmer temperatures brought out a few people who could be spotted walking in the parks of the huge metropolis. The scene would appear completely normal but for the fact they were wearing masks.

But as for work, few businesses are back to normal. Some businesses are up and running but many are implementing shifts, using only half their staff in rotation as new government rules apparently require a minimum of 2 square metres around each worker.

"We have been working from home for three weeks," says Emma (her chosen English name), "Next week we may go to the office, but not all the staff at the same time."

Being office based, working at home is an option. But for many businesses the lockdown has devastated business.

"Most restaurants and shops are still closed and for restaurants that are open, they're almost empty," says Emma, "Most people are on guard to avoid contact with strangers."

Even popular areas such as Sanlitun, an expat hotspot which is home to some of the city's most exciting places to eat, drink and party, is quieter than usual. "There are people, but far fewer than at normal times," she says.

These are not normal times, however. And it's difficult to see when life will return to normal, not only for the 20 million inhabitants of Beijing, but for the more than 1.4 billion people across China who are experiencing similar if not tighter restrictions.

tvnewswatch, London, UK