Examining the Link Between Destruction of Biodiversity and Emerging Infectious Diseases

Following are excerpts from six articles that explore how human destruction of biodiversity contributes to increasing disease threats. This exploration is especially timely and important given the current global coronavirus (or COVID-19) pandemic.

The COVID-19 pandemic is an incredible human tragedy. Today an estimated one million people have been infected by the virus, and over 50,000 have died. And, for the foreseeable future, those numbers will be rising sharply.

But this is not the first time a new disease erupted into the human population, causing significant harm. Consider the H1N1 influenza virus, SARS, MERS, Zika virus, Nipah virus, Hantavirus, and Ebola. Or consider the terrible toll of HIV. In fact, during the last few decades, the world has seen many “emerging” and “re-emerging” infectious diseases.

It seems odd that these emerging infectious diseases erupted into the world after the massive improvements in public health of the 20th century, when we saw the biggest gains in life expectancy in human history. The discovery and deployment of antibiotics, the widespread use of vaccinations, increased sanitation, better food and water security, and other medical miracles extended our lives and reduced human suffering. But it also gave us the illusion that infectious diseases were a thing of the past.

But recent decades have shown us that infectious diseases never really left, and they’re back with a vengeance.

Despite what some politicians and pundits are saying, this is not a surprise. Scientists have been ringing the alarm for decades, urging us to be better prepared. Countless reports have warned us during the last thirty years, including numerous pieces by Dr. Anthony Fauci. In the popular literature, Laurie Garrett warned us about this in her New York Times best-selling book, The Coming Plague in 1994. And Dr. Larry Brilliant spoke about this in his TED talk (which has over one billion views) in 2006.

They all warned us that changing environmental conditions were contributing to increasing disease threats. Numerous studies highlighted how infectious diseases could arise from deforestation, habitat and biodiversity loss, wildlife exploitation, the bushmeat and traditional medicine trade, confined animal agriculture, and antibiotic misuse.

Smart leaders knew this was coming. Scientists told them, again and again. And some wise leaders started to prepare. Sadly, others ignored the science, and some recently dismantled key programs needed to combat these threats.

So, here we are.

. . . While other factors can give rise to emerging infectious disease, human activities are a driver of many. In fact, back in 2005, my colleagues and I wrote an article in Science that pointed out that “Habitat modification, road and dam construction, irrigation, increased proximity of people and livestock, and the concentration or expansion of urban environments all modify the transmission of infectious disease and can lead to outbreaks and emergence episodes.”

We knew that the loss of habitats and biodiversity, breaking down natural ecological systems, and increasing contact between dense human populations, wild animal products, and poorly-regulated animal agriculture, was a recipe for disaster.

Many more studies have reinforced these conclusions. In a recent article by John Vidall, he concludes that the continued decline of biodiversity and habitat worldwide could lead to many more incidents like COVID-19.

– Jonathan Foley
Excerpted from “After the Storm”
Medium
April 2, 2020

The role of biodiversity in disease prevention has received increased attention of late. In a 2015 “state of knowledge review” of biodiversity and human health by the United Nations, scientists wrote that “an ecological approach to disease, rather than a simplistic 'one germ, one disease' approach, will provide a richer understanding of disease-related outcomes.” Recent research has given more support to the idea that biodiversity protection in one part of the world can prevent novel diseases from emerging and leaping into another.

It’s a numbers game, in part. Not all species in a community are equally susceptible to a given disease, nor are they all equally efficient transmitters. In diverse ecosystems well separated from human habitations, viruses ebb and flow without ever having a chance to make it to the big time.

But as people move in, those protections begin to break down. Disrupted ecosystems tend to lose their biggest predators first, and what they leave behind are smaller critters that live fast, reproduce in large numbers, and have immune systems more capable of carrying disease without succumbing to it. When there are only a few species left, they’re good at carrying disease, and they thrive near people, there may be nothing between a deadly pathogen and all of humanity.

– Eric Roston
Excerpted from “Want to Stop the Next Pandemic?
Start Protecting Wildlife Habitats”
Bloomberg via TIME
April 8, 2020

COVID-19 is not a separate issue from climate change. It is precisely because humans have so badly damaged the environment and thrown nature out of balance that novel epidemics are happening. COVID-19 is not a one off emergency that we will sort out and be done with. It may be the new normal. Climate change will bring with it cascading catastrophes. We will not be able to manage one before another hits. The only chance we have is to act immediately and on a scale humanity has not done before.

– McAuley Hentges
via Facebook
April 20, 2020

There’s misapprehension among scientists and the public that natural ecosystems are the source of threats to ourselves. It’s a mistake. Nature poses threats, it is true, but it’s human activities that do the real damage. The health risks in a natural environment can be made much worse when we interfere with it. Rodents and some bats thrive when we disrupt natural habitats. They are the most likely to promote transmissions [of pathogens]. The more we disturb the forests and habitats the more danger we are in.

– Richard Ostfeld
Quoted in John Vidal's article, “'Tip of the Iceberg':
Is Our Destruction of Nature Responsible for Covid-19?”
The Guardian
March 18, 2020

We must stop talking about everything as it benefits us and start realizing that the reason for this pandemic now is because we have shown so little respect for the natural world, with destroying more and more forest and animal species being pushed together. Viruses spilling over from one species to another, which normally wouldn't [happen]; animals pushed into closer contact with people [farming], for example, another opportunity for spillover of viruses. And then of course, the animal trafficking and export and the number of animals that are being sold in these so-called wet markets in Asia, but also the bushmeat in Africa.

These viruses have been predicted for many years and [were written about] in the book Spillover: Animal Infections and the Next Human Pandemic by David Quammen. People haven't listened; they haven't learned from the last SARS epidemic.

The silver lining [of this current pandemic] is that many people for the first time ever have breathed clean air, because with the shutdown of some of the big businesses the air has become cleaner in places like Mumbai and Beijing.

The hope is that enough people will realize what they've been missing, [that there will be] a groundswell of people determined somehow to persuade business and government to do things differently, to have a different mindset. And unfortunately, materialism and big business being what it is, I fear that business will work even more quickly to catch up on all the revenue they've lost, and it's a real conundrum because of business shutdown, commercial things being closed down. People have lost their jobs, and they're suffering.

On the other hand, it's giving a respite to nature. So we have to find a balance, we have to get back to a different way of doing things.

– Jane Goodall
Quoted in Kathleen Rellihan's article, “Jane Goodall Says
Pandemic Is Due to 'Little Respect for the Natural World.'
But There's Hope for This Planet Yet”
Newsweek
April 22, 2020

If we fail to understand and take care of the natural world, it can cause a breakdown of [biodiverse] systems and come back to haunt us in ways we know little about. A critical example is a developing model of infectious disease that shows that most epidemics – AIDS, Ebola, West Nile, SARS, Lyme disease and hundreds more that have occurred over the last several decades – don’t just happen. They are a result of things people do to nature.

Disease, it turns out, is largely an environmental issue. Sixty percent of emerging infectious diseases that affect humans are zoonotic – they originate in animals. And more than two-thirds of those originate in wildlife.

We destroy them and they gift us self-destruction keys.

– Jim Robbins
Excerpted from “The Ecology of Disease”
The New York Times
July 15, 2012

Related Off-site Links and Updates:
Without “Transformative Change” to Global Economic Systems, Humans Risk Causing More Deadly Pandemics – Julia Conley (Common Dreams, April 27, 2020).
Amid Dual Crises of Climate and Covid-19, World Leaders Told “Empty Words Will Not Help Us” – Jessica Corbett (Common Dreams, April 28, 2020).
She Predicted the Coronavirus. What Does She Foresee Next? – Frank Bruni (The New York Times via Yahoo! News, May 4, 2020).
The Indigenous Communities That Predicted Covid-19 – Rachel Nuwer (BBC Travel, May 4, 2020).

See also the previous Wild Reed posts:
• An Infectious Disease Specialist Weighs-in on Covid-19
• A Prayer in Times of a Pandemic
• Hope and Beauty in the Midst of the Global Coronavirus Pandemic
• The Calm Before the Storm
• Marianne Williamson: In the Midst of This “Heartbreaking” Pandemic, It's Okay to Be Heartbroken
• In the Midst of Crisis, Learning Resistance and Vision-Seeking from the Indigenous and African-American Experience
• Something to Think About – February 10, 2020
• Quote of the Day – April 18, 2020
• Something to Think About – April 22, 2020

Image: Photographer unknown.