Mother Nature’s Fever: How Deforestation Causes Disease
An Issue of Now:
Forest destruction is a more urgent issue than most people think. We now know it’s a major cause of disease as well as air pollution. How does deforestation cause disease?
It’s taken Covid-19 to finally shine a global light on this question.
In 2020, one month into the global effort to manage the pandemic with sanitary measures, deforestation was 63 percent higher in Asia and the Americas than during the same period in 2019.
The sudden removal of millions of trees inevitably led to a global rise in disease. (Brancalion et al.)
Logically, we can assume that infiltrating the home of nearly 80 percent of the Earth’s wildlife would create some imbalance. Animals flee their habitats in search of new homes, causing more animal-human interaction.
How Does Deforestation Cause Disease – CIRAD Explains:
In the words of French Agricultural Research Centre for International Development (CIRAD) ecologist and infectious disease specialist Serge Morand:
“We know that the risks of infectious disease emergence are greater in tropical regions with high deforestation rates. Increased deforestation means increased interactions between wildlife, which is a reservoir of as yet unknown viruses, and human activity, notably agriculture.”
Morand observes that since the 1940s, nearly half the viruses jumping from animals to humans have had agricultural links. Clearing forests to turn them into farmland opened the door for potentially deadly illnesses such as:
– yellow fever
– West Nile virus
and Lyme disease.
Even more alarmingly, the editors of Scientific American opened this June 2020 article with:
” SARS, Ebola, and now SARS-CoV-2: all three of these highly infectious viruses have caused global panic since 2002.”
They continue with this dire warning “and all three of them jumped to humans from wild animals that live in dense tropical forests.”
Our Understanding on How Does Deforestation Cause Disease:
Only last week, a CIRAD research article linked changes in forest cover with outbreaks of several vector-borne and zoonotic diseases, including:
– scrub typhus
– dengue or chikungunya
– Chagas disease
– Lassa virus
The article noted that commercial palm tree afforestation (planting palms in areas where they hadn’t previously grown) also plays a significant role in transferring disease. (Morand et al.)
The CIRAD researchers cited another study (Vijay et al.) showing how these diseases also impact countries like Thailand, which has no deforestation, and China and Vietnam, which practice reforestation!
This 2019 Daily Observer article, for example, highlights how palm tree plantations replacing cleared forests spread disease in Liberia. The plantations’ abundance of palm fruit attracted hordes of forest-dwelling mice.
The mice carried the Lassa virus into their new environment and spread it to humans with a 36-percent fatality rate.
The CIRAD research article also cites studies linking deforestation to the spread of:
– Ebola (Rulli et al.)
– Nipah or Plasmodium knowlesi (Pulliam et al.)
– malaria (MacDonald et al.)
– Zika virus (Zahouli et al.)
Peter Daszak, president of the nonprofit global infectious disease tracking Ecohealth Alliance, tweeted in 2019 that “…nearly one in three outbreaks of new and emerging disease[s] are linked to land-use change like deforestation.”
Human interference with nature has changed the flow of things and created many opportunities for diseases to spread. Deforestation, in particular, reduces animal habitat and makes an environment ideal for pathogenic reproduction.
University of Florida scientist Amy Vittor proposed a mechanism that may have increased malaria’s spread. She states that clearing patches of forest leads to an ideal breeding habitat for the Plasmodium knowlesi strain of malaria.
Even in the absence of humans, surprisingly high amounts of the malarial strain Plasmodium falciparum are now present in Brazil’s Atlantic tropical forest.
This raises the possibility that it’s infecting new world monkeys. If so, deforestation probably facilitated the cross-infection (Araujo et al.).
Deforestation hasn’t only raised the risk of human infection; it’s now affecting the animals themselves. This spread will only cause a greater one, which is never a good thing.
What This Could All Mean:
– We have a very well-documented experience with zoonotic diseases. We have only to look at history to grasp what increasing their spread could mean.
-The ebola virus outbreak at the beginning of 2014 infected 28,652 people, of whom 11,325 (40 percent) lost their lives. (CDC).
– Yellow Fever:
– In the early 1990s, yellow fever broke out for the first time in Kenya’s heavily deforested Kerio Valley; Yellow fever causes severe kidney, heart, and liver disease. (Reiter et al.)
– Non-natural interaction with bats led to the spread of an unseen variation of the coronavirus. This virus infected more than 127 million people, and global deaths are nearing three million.
Continuing deforestation will only increase such outbreaks. Our battle with pathogens is eternal and inescapable. Unfortunately, we can’t rely on current science and medicine alone to win the war.
Researcher Recommendations for Public Authorities:
- Protect rural and indigenous communities. They have the highest exposure and vulnerability to infectious diseases, mainly due to their limited health care access.
- Make halting deforestation a priority in tropical zones. Doing so will require us to look beyond economical self-gain.
- Anticipate more forest fires ahead of the tropical-zone dry season.
- Support legal timber markets and supply chains.
The question “How does deforestation cause disease?” is something billions of more people should be asking but aren’t.
It’s up to those who understand the connection to combine our efforts and spread accurate information. Only then can we hope to shape a more positive future.
Mother Nature is calling for change, and it’s time for us to answer!