FOR those genuinely interested in ‘the science’ of coronavirus, a recent article on how China’s ‘batwoman’ hunted down viruses from Sars to Covid-19 is a must-read. The original article was published online on March 11, and it’s been updated for inclusion in the June issue of Scientific American to address rumours that SARS-CoV-2 emerged from Shi Zhengli’s lab in China.
Wuhan-based virologist Shi is well known for having identified dozens of deadly SARS-like viruses in bat caves that she’s been tracking down since the 2004 outbreak. It’s a fascinating if not horrifying story of how the pathogen hunters’ nightmarish and gruelling quest paid off. Less dramatically compelling but equally important are her team’s discoveries about the unique nature of this latest pathogen.
By January 7 this year, the Wuhan team had determined that a new virus had caused the disease from which patients were suffering.
This was when they discovered that a genomic sequence of the virus, eventually named SARS-CoV-2, was 96 per cent identical to that of a coronavirus the researchers had identified in horseshoe bats in Yunnan. Their results appeared in a paper published online on February 3 in Nature which made it ‘crystal clear that bats, once again, are the natural reservoir’, according to other scientists not involved in the study.
The Scientific American article also focuses on the question of the region’s wildlife markets which sell a wide range of animals including bats, civets, pangolins, badgers and crocodiles, and are agreed to be perfect viral melting pots. Although humans could have caught the deadly virus from bats directly, ‘independent teams have suggested that pangolins may have been an intermediate host. These teams have reportedly uncovered SARS-CoV-2-like coronaviruses in pangolins that were seized in anti-smuggling operations in southern China’.
As a result China announced a permanent ban on wildlife consumption and trade except for research, medicinal or display purposes. Yet as Shi says, wildlife trade and consumption are only part of the problem:
‘In late 2016 pigs across four farms in Qingyuan County in Guangdong – 60 miles from the site where the SARS outbreak originated – suffered from acute vomiting and diarrhea, and nearly 25,000 of the animals died. Local veterinarians could not detect any known pathogen and called Shi for help. The cause of the illness –swine acute diarrhea syndrome (SADS) – turned out to be a virus whose genomic sequence was 98 per cent identical to that of a coronavirus found in horseshoe bats in a nearby cave.’
The article is here for you to read.
Meanwhile, hurt me though it does, I point you to the BBC and to their science correspondent David Shukman and his thought-provoking report, The mystery of asymptomatic ‘silent spreaders’ on the fact that the majority of people infected with Covid-19 to date don’t know they have had it or got it. As a contagion this makes it as opposite as can be to the experience of regular flu, when you either have the symptoms or don’t have the illness at all.
Policy-makers, however, should not be persuaded into using the evidence of the virus being passed by people who have no idea that they have it as an excuse for locking down society.
Examples of the high proportion of asymptomatic cases include the viral hotspot of the cruise ship Diamond Princess: it turned out that three-quarters of those on board who had tested positive had no symptoms. At a care home in Washington State more than half the residents were positive but had no sign of the illness.
Typically, Shukman’s report rests on the assumption that governments and scientists are capable of managing and controlling all things, not least the climate. It is the hubris of the scientific and technological and management revolutions. It is the thinking behind ‘waiting for a vaccine’. In truth, human society will not survive on this level of risk aversion and assumption that we can and must control every aspect of our environment and lives.
Rather we should see it as massively reassuring that by far the majority of people infected are asymptomatic and entirely untroubled by the illness, the bottom line being that the only people who may want to be or need to be risk averse are the minority that are the most vulnerable to the symptoms.