Jared Diamond is a biologist, geographer and anthropologist, the author of several bestsellers. He is also a Pulitzer Prize winner. Nathan Wolfe is an American virologist, founder of the Global Viral laboratory. The two scientists warn here of the risk of other pandemic episodes favored by globalization.
It is time to plan for the management of the next epidemic. No. It is not too early to address this issue now, although the Covid-19 pandemic is still at an early stage. The SARS (Severe Acute Respiratory Syndrome) epidemic, which struck the world in 2003, has given rise to no reflection on the management and prevention of the next health crisis. While it would have been possible to avoid the current Covid-19 epidemic, we are now paying the price for this failure to anticipate, which allowed the virus to spread by very probably following the same path as the Sras.
Emerging human diseases, whether Covid-19 and SARS but also AIDS, Ebola and Marburg, do not occur in humans spontaneously. Originally, these are animal diseases (also called zoonoses) which are transmitted from animals to humans. These diseases come from mammals, the closest animal class to humans.
While it would have been possible to avoid the current Covid-19 epidemic, today we are paying the price for this anticipation failure.
The reason for this mode of transmission is simple: a microbe evolves by adapting to the internal chemical environment of its host. If the internal chemical environment of its new host is comparable to that of its old host, the microbe will be more easily transmitted. Humans are also mammals, so most of these zoonoses are more widely transmissible.
Transmission of SARS to humans has occurred in Chinese wild animal markets. Indeed, everywhere in China, there are many businesses of this type, where wild animals which have been killed or captured are sold, dead or alive, for food or medicinal purposes. The SARS epidemic originated in this small carnivorous mammal, the civet, which had itself been contaminated through the bat. However, if most people should never have been in contact with this wild animal, the commercial activity of hunters consists in reselling civets and other animal species on the stalls of these markets.
If an evil alien wanted to develop the most effective method of infecting humans with zoonoses, he would try to maximize his chances by bringing as many mammalian species as possible into contact with as many humans as possible. And what would this miraculous bias be? A Chinese market for wild animals!
Annoyingly, the stalls of these shops abound in animal species on which customers get supplies, all likely to be candidates for infection. Of course, these wildlife markets are not limited to China. However, Chinese businesses have the difference that they are formidable places conducive to the outbreak of an epidemic. Indeed, China has the highest population in the world, increasingly connected to the rest of the planet by high-speed trains, planes, cars.
The SARS epidemic in 2003 should have raised awareness
These facts concerning both the animal origin of these emerging human diseases and the ideal mode of transmission, favored by these wildlife trade, have been known to public health workers for many years. The SARS epidemic that entered these markets in November 2002 should have led to an awareness of China and the closure of these sites. She kept them open.
When Covid-19 first appeared in Wuhan in December 2019, the metropolitan market was quickly suspected of being at the heart of the virus. At the moment, although we don’t have the evidence to confirm this hypothesis, everything suggests that. Indeed, Covid-19 is caused by a coronavirus which is very similar to the two previous epidemics of zoonotic coronaviruses, Sras and Mers, the common source of which originates in bats.
After the emergence of the Covid-19, the Chinese government initially reacted by seeking to minimize its importance, before taking a 180-degree turn and implementing a drastic package of measures of a scale never seen in the past. It appears that these measures have proven to be effective in stemming the epidemic. In addition, China has also decided to prevent the emergence of other zoonoses by finally ending the food trade in wild animals.
This is the good news. But there is also bad news. The Chinese government has not banned all possible routes of transmission of an infectious disease from wild animals to humans. I am referring to the animal market at the center of traditional Chinese medicinal practices. This is another heavy trade, very busy and in which many animal species also accumulate. For example, the pangolin, a scaly anteater, is used extensively in traditional medicine. Popular belief is that its consumption helps fight fever, skin infections and venereal diseases. However, whether for food or medicinal purposes, the microbe makes no distinction between these two markets and can infect anyone who visits one of them.
Until the wildlife trade stops, the next epidemic is only a matter of time
For Westerners, the closure of these infectious foci is obvious. In fact, the question that arises is: why the Chinese government, whose authoritarian governance allowed it to quickly impose drastic measures on its millions of nationals, does it not have the will to put an end definitely to animal trafficking? The explanation is that animal products are more than just a delicacy for some Chinese populations. By comparison, if scientists discovered that wine and cheese regularly caused epidemics, how would the French react if it were necessary to ban trade in these products? In China, the consumption of wild animals is an integral part of the culture, and even much more than that of cheese and wine in France.
On the other hand, as long as this trade in wild animals does not end definitively, in China as elsewhere, we are confident that another global epidemic will follow those of Sras and Covid-19. We have been relatively spared by SARS since the toll has remained below 1,000 deaths, much less than that of the seasonal flu responsible for hundreds of thousands of deaths each year. However, we won’t get away with the Covid-19 so well. Whether it causes more or less deaths than the seasonal flu, it will inevitably have a dramatic impact on the lives and work of millions and even billions of people around the world.
And the consequences of the next virus could be even worse. Growing globalization is increasing the flow of people and trade. Biologically, there is therefore no reason why future epidemics should not cause hundreds of millions of deaths and a depression unprecedented in history, which has lasted for several years.
Such a risk would be considerably reduced by ending the markets for the sale of wild animals for food and traditional medicine. This is not a favor from the Chinese government to the rest of the world, but a measure beneficial to the Chinese people themselves. As in the case of Covid-19, they will probably be the first victims of the next virus that will emerge from these businesses.