Coronavirus: How environmental destruction influences the emergence of pandemics

There have now been more than one million cases of COVID-19 worldwide and tens of thousands of deaths.

Many cities and countries across the globe are under lockdown or have implemented strict measures to ensure people stay in their homes. Health officials are encouraging physical distancing from others, as well as frequent handwashing and respiratory hygiene.

The world as humanity knows it has changed, and that’s prompted many to wonder: How did we get here? And is it possible that environmental destruction and climate change have contributed to where we are today?

While experts say it’s too early to tell whether the novel coronavirus could be connected to climate change, many researchers had sounded the alarm for years that some sort of pandemic was coming — largely due to how the world has developed.

“It’s been well known for the past 30, 40 years…that the greatest threat to humanity from a virology perspective is a pathogenic respiratory RNA virus,” said Marc-André Langlois, the Canadian Research Chair in molecular virology and intrinsic immunity, and a professor in the faculty of medicine at the University of Ottawa.

“If there’s one virus that will wipe out a large swatch of humanity, it would be this type of virus.”

1:41 Coronavirus outbreak: Canada surpasses 11,700 cases, over 290,000 tests completed

Zoonotic disease transmission

Zoonoses are diseases and infections that can be naturally transmitted from animals to people.

Humans can get these sporadically or routinely, but sometimes, the diseases evolve and can only pass between people, according to Craig Stephen, who’s a professor at both the University of Saskatchewan’s Western College of Veterinary Medicine and the University of British Columbia’s School of Population and Public Health.

“This pathogen is usually endemic in animal species,” Langlois said. “Somehow, that pathogen that normally should not infect humans developed some genetic adaptations to infect humans.”

Zoonoses can be passed from an animal to a human indirectly or directly through a vector, Langlois said, adding that bats can be prime reservoirs for dangerous viral pathogens.

“The first step that has to happen is something changes, usually caused by us, that brings us into close contact with this wildlife species,”said Chelsea Himsworth, the B.C. regional director at the Canadian Wildlife Health Cooperative and a professor at the University of British Columbia’s School of Population and Public Health.

“Then the virus has to actually transmit.”

Environmental destruction and human encroachment

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There are a number of drivers that can contribute to the emergence and transmission of diseases, including climate change, globalization and land use changes, such as urbanization and deforestation, according to Katie Clow, a One Health professor at the Ontario Veterinary College at the University of Guelph.

“The density of human populations is increasing,” Langlois said. “Because of deforestation and global warming, this is enhancing the ability of arthropods — mosquitoes, in particular — to transmit zoonotic disease.”

Climate change disrupts the global ecosystem and causes species to move around, said Colin Carlson, an assistant research professor at the Center for Global Health Science and Security at Georgetown University.

“Health is probably the most personal way that we feel climate change,” Carlson said. “We do know that climate change means more Lyme disease throughout the northeast in Canada and the U.S.”

But Stephen said it’s not just climate change and habitat destruction that’s happening. After the 1950s, he said, there was something called the “great acceleration,” where human populations started to grow, international travel increased and carbon pollution rose.

“That great acceleration, yes, climate change is part of it, but climate change is just one of the major challenges we have with these great global changes, none of which act independently,” Stephen said.

When talking about global pandemics, he noted it’s important to examine human connectivity and how certain “edges” between interfaces are changing and developing.

2:51 COVID-19 survivors answer viewers’ questions

“We are connecting ourselves more intimately and more rapidly with our global neighbours,” Stephen said. “That’s one of the big, big things that says a pandemic is more likely to happen now than it was previously.”

Humans are also changing their edges with nature by fragmenting their habitat, he said, adding that climate change is also transforming ecology, which is allowing for different avenues in which pathogens can move around.

“We have a very anthropocentric view of the world — it’s sort of all about us, and no one cares until it’s causing a pandemic,” Himsworth said.

“By the time it’s causing a pandemic, it’s too late.”

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One Health, one world

One Health is an approach to creating and incorporating policies, research and programs that allow multiple sectors to work together to create better public health outcomes, according to the World Health Organization.

“One Health is a concept that’s been around for a while, but it’s really gaining traction, particularly within the last decade,” Clow said.

“It’s an approach that looks at how animal health, human health and environmental health are really interconnected.”

If people go beyond the traditional perspective of disease, Clow added, they need to think about the ecological factors and social conditions that support it and its transmission.

“It really helps you get a bigger picture about what sort of factors are playing into the entire disease process.”

According to Carlson, One Health approaches have helped scientists trace diseases back to wildlife and build surveillance systems that keep track of diseases.

“That does help us contain outbreaks much earlier,” he said, although that doesn’t mean One Health solutions can stop the current COVID-19 pandemic.

“They might have prevented it, and they may have already prevented other ones that otherwise would have happened,” Carlson said.

“Right now, we’re in a situation for the next few months — potentially over a year — where the entire problem on our hands is a human-to-human transmission problem.”

For Himsworth, however, it’s important to look at incorporating One Health approaches in the future.

“What happens in a forest in Asia has the potential to impact the health and livelihood of someone in Abbotsford,” she said.

“That is, in a nutshell, this sort of One Health approach that everything is interconnected. I think we’ve felt for a long time like we need to have this sort of approach to health problems and haven’t really been able to operationlize it or see what that would look like in reality.”

Looking ahead

In the long run, climate change means people will be dealing with more disease outbreaks that are similar to COVID-19, according to Carlson.

“If we don’t do something lasting, either in terms of the wildlife end, in terms of developing vaccines, in terms of changing the way we respond to outbreaks early on, in terms of changing the way that we internationally coordinate the legal and governance end of the problem, this exact thing could happen again,” he said.

For Himsworth, people may not be able to stop certain diseases from emerging but they can do their best to prevent them.

“As a human society, we’re increasing our population, increasing our footprint on the earth. It may be that no matter what we do, we will be vulnerable to these,” she said.

“I think the one thing that we can do is being at least more thoughtful stewards of the natural world.”

Societies are addicted to consumption, Stephen said, which is driving carbon pollution, and that’s allowing climate change to happen.

“We’ve talked a lot about recycling, we’ve talked a lot about reusing, but none of that is going to work if we don’t reduce,” he added.

“Instead of just looking for signals of illness, death and disease, we need to look for signals of vulnerability…Flattening the curve should be proactive, rather than reactive.”

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According to Francois, developing a vaccine can also help combat future epidemic and pandemic threats.

“A lot of these respiratory viruses — the influenzas and all the coronas — share certain attributes,” he said.

“If there was a sincere and dedicated investment by government, we could develop vaccination platforms to quickly react to emerging epidemic and pandemic threats.”

5:05 Is a coronavirus vaccine on the way?