Covid-19 is a zoonosis – an infectious disease transmitted from animals to humans. Its impact has been catastrophic, with the current devastating health crisis set to be followed by a debilitating economic tsunami. And while all eyes may be on the pharmaceutical industry in the hope it will swiftly develop a vaccine or cure for Covid-19, the real question should be: how can we prevent future pandemics?
The risk of zoonoses emergence, which leads to pandemics, increases in line with the amount of contact between animals - predominantly wildlife - and humans. Indeed, it is a phenomenon we have experienced since Neolithic times, with changing patterns of human behaviour leading to spikes in the advent of diseases. During the agricultural revolution, for example, diseases such as mumps, smallpox and measles were transmitted to humans from livestock.
And since the 1960s the number of zoonotic diseases has soared again and, for the last decade, the scientific community has been warning of the likelihood of epidemics and pandemics, with the potential to kill millions of people. But why is this happening now and what can we do to stop it?
What is the root cause of zoonoses?
As the human population grows, we are encroaching more and more on territories once reserved for wildlife. This habitat loss is a threat to biodiversity and has triggered a wave of mass extinction. While many species have been wiped out, some generalist animals, such as bats, rats and mosquitos have been able to adapt and survive. These animals typically possess a strong immune system which means they are an ideal reservoir to an array of viruses and other pathogens, carrying the diseases and readily passing them on to humans and other mammals while remaining asymptomatic themselves. This is particularly true of bats, the only flying mammal, which represent a quarter of all mammal species and have an innate immune system making them the perfect carriers and super-spreaders.
While the logical solution is to ensure that wildlife is diffused across a wide area and kept far from human settlements, by destroying wildlife habitat we are creating a situation where animals are crammed into much smaller areas. This creates the perfect storm, with the wild animals made more vulnerable and, at the same time, brought closer to us and our farms. This increases the risk of contamination through contact with the animal hosting the virus, either through insect bites, as in the case for the Zika virus or via a bridge host, for example from a bat to a domestic or farm animal, like the camel for MERS in 2012.
Our modern civilisation, with its cult of over-consumption, urbanisation, intensive farming and reckless industries, is deforesting every year more than 20 million hectares of forest in several regions of the world such as Brazil, Indonesia or the Democratic Republic of the Congo.
The role of our unsustainable lifestyles was unequivocally demonstrated in the Nipah virus outbreak in Malaysia in 1998. This Muslim country does not consume pork and yet replaced precious forest with palm oil plantation and mega pig farms to meet demand from the West. Bats lost their habitat, settled near the farms causing a fatal spillover to pigs then to humans.
Lack of biodiversity and resilience
Besides the risk of this direct transmission of pathogens, reducing biodiversity makes ecosystems more fragile, providing more opportunities for zoonotic diseases and other pathogens to thrive.
This becomes apparent when studying Lyme disease, a bacterial infection causes damage to joints and the nervous system if not caught early. It was first recorded in the UK in 1977 and, since then, the number of cases is rising steadily - up to 8000 diagnoses in 2019 and doubling every five year.
Furthermore, intensive farming, fossil-fuel industries and other greenhouse-gas emitters are amplifying climate disruption, contributing to this massive habitat and biodiversity loss. A perfect illustration of this came at the beginning of this new decade in the form of the Australian megafires, which obliterated more than 12 million hectares.
Global travel and social flaws
While historically most zoonotic diseases remained local, global travel and worldwide interconnection has given them and other pathogens a springboard to go viral all over the planet. Luckily, most of these host jumps are unsuccessful, but the relentless and rapid mutation of viruses can soon reverse this fortune, with devastating effects.
Moreover, our modern societies unwittingly give infectious diseases an advantage, with factors as diverse as air pollution and obesity making us more vulnerable to Covid-19 and other infectious diseases. The fact an eighth of the global population lives in overcrowded slum conditions with poor hygiene is another aggravating factor in amplifying the likelihood of an epidemic taking hold, as well as making its impact more severe when it does occur.
How to avoid another pandemic
Now is the time for One Health approach encompassing public health, animal welfare and the state of our planet, according to Dr. Claire Lajaunie, an environmental lawyer, who urges international institutions and national governments to discuss this approach further.
“Globalisation, land use and how we treat wildlife need to be considered together, not in isolation of one another,” she says during a discussion with MAINTENANT on the current crisis.
Further, David Quammen, a science investigator and author of “Spillover: Animal Infections and the Next Pandemic”, believes that while it is inevitable there will be another pandemic, its scale will be determined by the actions we choose to take.
He explains: “There will be another pandemic. And whether it is a big one like this or even worse depends on what we do on the level of our preparedness.
“We can reduce the number of spillovers and, therefore, the danger of pandemics by adjusting our relationship with the natural world.”
In order to do this, it is vital to preserve and restore biodiversity. This would serve to increase animal and human resilience and make us less exposed to zoonotic diseases and other pathogens. Meanwhile, on an individual level, we are urged to change our lifestyles, living sustainably, reducing consumption, and moving towards a plant-rich diet.
“In addition, we should be looking to travel better and less often, enjoying local places more,” says Dr Serge Morand, evolutionary ecologist and author of “The Next Plague”. “We should develop new, sustainable tourism, which would actually bring many local job opportunities.”
He also targets fashion, finance, and other industries to do their part too, embedding genuine sustainability in their business models.
“Instead of having huge mega malls with millions of shoppers, we could go back to doing our errands locally in our own community,” he continues.
More broadly, civil society has a major role to play in putting pressure on governments and corporations. The underlying legal and fiscal structures in our societies need to be revised at a global and local level to include sustainability at their core, as opposed to the piecemeal environmental legislations that are scattered here and there with little cohesion. To be successful in the enormous endeavour, worldwide collaboration is crucial. To work at a local level, implementing pragmatic and efficient solutions is essential.
In short, zoonotic pandemics are just another manifestation of the negative impact we are having on our planet, with both biodiversity degradation and climate disruption.
More than two-thirds of emerging infectious diseases are zoonotic, so the good news is that by tackling these unprecedented environmental challenges, it automatically reduces the risk of pandemic outbreaks as it is the same battle.
So, with no more delay, no more procrastination, let’s do what must be done.