Here’s a “big picture” look at the root cause of the virus spread, and the ensuing pandemic. While I don’t expect my blog readers to magically wave a wand and eliminate pandemics, I’ll follow with some specifics you can do to help prevent them … and improve our quality-of-life experience, as well.
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‘Promiscuous treatment of nature’ will lead to more pandemics – scientists
Habitat destruction forces wildlife into human
environments, where new diseases flourish
Global environment editor
7 May 2020
Humanity’s “promiscuous treatment of nature” needs to change or there will be more deadly pandemics such as Covid-19, warn scientists who have analysed the link between viruses, wildlife and habitat destruction.
Deforestation and other forms of land conversion are driving exotic species out of their evolutionary niches and into manmade environments, where they interact and breed new strains of disease, the experts say.
Three-quarters of new or emerging diseases that infect humans originate in animals, according to the US Centers for Disease Control and Prevention, but it is human activity that multiplies the risks of contagion.
A growing body of research confirms that bats – the origin of Covid 19 – naturally host many viruses which they are more likely to transfer to humans or animals if they live in or near human-disturbed ecosystems, such as recently cleared forests or swamps drained for farmland, mining projects or residential projects.
In the wild, bats are less likely to transfer the viruses they host to other animals or come into contact with new pathogens because species tend to specialise within distinct and well-established habitats. But once land is converted to human use, the probability increases of contact and viruses jumping zoonotically from one species to another.
As natural habitats shrink, wild animals concentrate in ever smaller territories or migrate to anthropogenic areas, such as homes, sheds and barns. This is particularly true of bats, which feed on the large number of insects drawn to lamplight or fruit in orchards.
Two years ago, scientists predicted a new coronavirus would emerge from bats in Asia, partly because this was the area most affected by deforestation and other environmental pressures.
One of the authors, Roger Frutos, a specialist in infectious diseases at the University of Montpellier, said multiple studies have confirmed the density and variety of bat-borne viruses is higher near human habitation. He said:
“Humans destroy the bats’ natural
environment and then we offer them
alternatives. Some adapt to an
in which different species cross
that would not cross in the wild.”
With deforestation and land-use
change, you open a door
Habitat destruction is an essential condition for the proliferation of a new virus, he added, but it is only one of several factors. Bats also need to pass the disease on to humans. There is no evidence of this being done directly for coronaviruses. Until now there has been an intermediary – either a domesticated animal or a wild animal which humans came into contact with for food, trade, pets or medicine. In the 2003 Sars outbreak in China, it was a civet cat. In the Mers outbreak in the Middle East in 2012, it was a camel.
Scientists are not yet certain of the animal for Covid-19, though Frutos said initial theories that a pangolin was the intermediary now seem less likely.
In a soon-to-be-published paper in Frontiers in Medicine, Frutos and his co-authors argue the key to containing future epidemics is not to fear the wild, but to recognise that human activities are responsible for the emergence and propagation of the zoonosis. “The focus must be on these human activities because they can be properly organised,” notes the paper titled, the Conjunction of Events Leading to the Pandemic and Lessons to Learn for Future Threats.
Scientists have detected about 3,200 different strains of coronavirus in bats. Most are harmless to humans, but two very closely related sarbecoviruses found in east Asia were responsible for Sars and Covid-19. The paper says future sarbecovirus emergence will certainly take place in east Asia, but epidemics of other new diseases could be triggered elsewhere.
South America is a key area of concern due to the rapid clearance of the Amazon and other forests. Scientists in Brazil have found viral prevalence was 9.3% among bats near deforested sites, compared to 3.7% in pristine woodland. “With deforestation and land-use change, you open a door,” said Alessandra Nava, of the Manaus-based Biobank research centre.
She said diseases were naturally diluted in the wild, but this broke down when humans rapidly disrupted the ecological balance. As a local example, she pointed to Lyme disease, which has spread to humans through capybaras. Some municipalities are culling the giant rodents to prevent contagion, but Nava said this was not necessary in pristine forests that still had jaguars. She said:
“You don’t find Lyme disease in areas with
jaguars because they keep the capybara
numbers in check. The problem is when you
put different species that aren’t naturally
close to one another in the same environment.
“That allows virus mutations to jump to other
species. We have to think about how we treat
wild animals and nature. Right now we deal
with them far too promiscuously.”
Her conclusions were echoed by Tierra Smiley Evans, an epidemiologist at the University of California who studies virus distributions in the rapidly degrading forests of Myanmar. She has found that endangered or threatened species are more likely to have viruses than animals at lower risk of habitat loss and hunting. She said the connection between environmental stress and human health had been made more apparent by Covid-19 pandemic. She said:
“I’m hopeful that one of the most pos-
tive things to come out of horrible
tragedy will be the realisation that
there is a link between how we treat
the forest and our wellbeing. It really
impacts our health. It is not just a wild-
life issue or an environmental issue.”
To prevent future pandemics, the academics said international cooperation was needed to encourage monitoring and education at a local level so that virus outbreaks could be detected and contained at an early stage. Although this would be expensive, they said it would more economically efficient than waiting for an outbreak to become a pandemic, which forces the world into lockdown.
They also emphasised that bat culls and bans on wet markets were likely to be ineffective and could prove counterproductive because bats play an important role in insect control and plant pollination. Evans said:
“Living safely with bats is what we should
be focusing on, not eliminating them.”
Conservation groups have also urged greater protection of existing habitats. A recent Greenpeace report warned the Amazon could see the next spillover of zoonotic viruses because the Brazilian president, Jair Bolsonaro, is putting a higher priority on opening up the forest than protecting people’s health. Daniela Montalto, Greenpeace forests campaigner, said:
“It’s unforgivable. His appetite for destruct-
tion is fuelling the current health crisis and
will make future crises we face even worse.
He must be stopped and forest protection pri-
oritised. Without it, we will all pay the price.”
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Our goal should be to protect as much wild land as possible. But specifically how can we do that?
- Support land trusts or organizations such as the Nature Conservancy. You can donate money, of course, but you can also donate time. They need volunteers for trail maintenance or to take out invasive species that don’t belong. They also need people to simply walk the land to ensure that trees are not being illegally harvested, or to report illegal hunting.
- There are places – by different names in different areas – that support injured animals and birds and help them get back into the wild. Perhaps Google “wildlife support organizations,” or ask local zoos for names. Again, you can volunteer time or contribute funds.
- You can also support organizations that are working to prevent destruction of natural habitats, such as Greenpeace, Tree Sisters, World Wildlife Fund. They all need funds, especially in these difficult economic times. Most also need volunteers, with a huge the range of activities from which to select.
- While this last suggestion will vary with your specific home situation, try to keep some land on your property “in the wild.” Let the grass grow long even in a small area, if permissible. Plant native plants where possible. (Google “native plants,” specifying your area. Or ask the native plant society in your area – and most states have one.)
- There are also organizations that protect bodies of water, such as the Chesapeake Bay Foundation, or River Keepers. If you’re more oriented to our waterways, contact them, instead of land trusts.
- Grasses are native in most areas. Grass lawns, however, are useful when you want essentially an outdoor carpet, for recreational use. If that’s not the intended use, then using chemicals and mowing is a waste of time and money. If you live in the jurisdiction of a homeowner’s association, ask to have their rules changed, so people can let non-recreational areas become more natural habitats.
Most of the organizations that protect land, such as land trusts, have walking trails. So volunteering to help them can also provide you with some enriching leisure activity.
Decades ago, President Kennedy initiated the Peace Corps. People volunteered to go to another country and contribute their time and expertise to help people there. Yes, it was helpful to those communities. And it helped our national relationship with those countries. But … if you’ve spoken with any … it was also a gratifying and life-enriching experience for those volunteers.
Similarly, helping to restore habitats will certainly help eliminate future pandemics. But … it can also become an enriching life experience for us … a true “win-win” outcome.