“It is highly likely that future SARS or MERS-like coronavirus
outbreaks will originate from bats, and there is an increased probability that this will occur in China” — this is what a study concluded in January 2019.
Table of contents
A different virus
Coronaviruses aren’t a novel thing. We’ve known them for decades, both in humans and in animals. You’ve probably had one before, too — if you’ve ever suffered from one of those nasty, feverish colds, there’s a good chance it was caused by a coronavirus.
But this one’s different.
We’ve been dancing around those four words for a while now. Many were quick to point out that influenza kills many more people than the coronavirus, completely missing the point that this is an active outbreak where the number of cases surges day by day.
This novel coronavirus seems to be positioned in a viral sweet spot: it’s contagious enough to be passed around like a flu, it’s lethal enough to be very dangerous, but not lethal enough to prevent its transmission by hosts (most importantly, humans). There’s nothing inherently different about this virus that we can tell so far, but it just seems to have hit a sweet spot that allows it to proliferate in humans.
Here’s the catch though. We knew something like this was coming.
With startling accuracy, a group of Chinese researchers predicted the emergence of a coronavirus epidemic. They predicted it would emerge from bats, and they also predicted it would start from China.
“Fifteen years after the first highly pathogenic human coronavirus caused the severe acute respiratory syndrome coronavirus (SARS-CoV) outbreak, another severe acute diarrhea syndrome coronavirus (SADS-CoV) devastated livestock production by causing fatal diseases in pigs,” the study read. “Both outbreaks began in China and were caused by coronaviruses of bat origin. This increased the urgency to study bat coronaviruses in China to understand their potential of causing another virus outbreak.”
Surprisingly many human viruses started out in bats. The dreadful Ebola and Marburg, as well as rabies, started out in bats. Bats are what scientists call a “viral reservoir”, and there are several reasons for this propensity.
For starters, bats are the only mammals capable of flight, which means they tend to have a long-range of migration, picking up and passing pathogens as they go. They’re also a very diverse group, accounting for about a fifth of all mammalian species, and are distributed almost everywhere in the world.
Bats also have weird immune systems. Bats’ immune systems are relentless, constantly mounting defenses against pathogens. They act quickly and efficiently, destroying viruses with unforgiving speed. But one the other hand, their antibodies seem to have a relatively shorter lifespan, which makes them more prone to reinfection. This essentially makes bats a breeding ground for super-viruses.
Look at it this way: on one hand, bats’ immune systems produce a swift response, encouraging viruses to reproduce as quickly as possible if they want to have a chance. At the same time, immunization is low, and reinfection is common, so the same viruses can fight a bat’s immune system time and time again, growing stronger as they do so. Add in the vigorous lifestyle and long lifespan of bats, and you start to see why so many viruses come from bats.
The problem is that while bats can generally handle these infections, other species aren’t as effective.
We’ve mentioned before that bats are spread everywhere on the globe. Sure, they can breed superviruses, but why would China be different?
In the same study, Yi Fan and colleagues predicted several reasons why the next coronavirus (this one) will start from China.
For starters, the majority of coronaviruses can be found in China, and many bat colonies live in or around densely populated areas. But there’s more than just this innate distribution of bats and viruses, researchers note. Namely, hygiene — or the lack of it.
“Chinese food culture maintains that live slaughtered animals are more nutritious, and this belief may enhance viral transmission. [..] In this regard, China is a likely hotspot. The challenge is to predict when and where, so that we can try our best to prevent such outbreaks,” the study reads.
China isn’t the only country whose meat-eating culture features some unhygienic practices, but it is definitely one of the leading ones. The famous wet markets, where live animals (both wild and domestic), meat, and other foods are sold together with little concern for hygiene make for an excellent viral gateway both for intraspecies and interspecies transmission.
The other reason, which was not mentioned in this study but was addressed numerous times in regards to this outbreak, is wildlife trade. China has the largest market for wildlife trade and bats are not an exception. This can also encourage viruses to jump from bats to other species.
Listen to scientists
“Two bat origin CoVs caused large-scale epidemics in China over fourteen years, highlighting the risk of a future bat CoV outbreak in this nation,” the study concludes.
“Therefore, the investigation of bat coronaviruses becomes an urgent issue for the detection of early warning signs, which in turn minimizes the impact of such future outbreaks in China.”
Of course, the study didn’t predict this exact outbreak — it merely highlighted that a coronavirus outbreak emerging from bats in China is likely. This prediction turned out to be incredibly accurate.
The study didn’t really cause an uproar. Major publishers didn’t cover it, and even in China, it didn’t really receive much attention. Policies weren’t changed, and life continued as usual.
There’s a certain degree of coincidence that the study’s prediction was shown true just one year later, but there’s also an important message within. Most times, crises don’t really happen out of the blue — we see them coming. We know some things are bad, and yet we can’t be bothered to act and reduce the risks. In this case, it was a virus from bats in China, but it could have been a number of other things just as well.
The science is usually there, and studies are good at warning us of risks. We just have to get better paying attention.