Green Generation – Zoonosis

Our May’s episode is Zoonosis, a scientific and environmental explanation of the COVID-19 pandemic. Only for Patreon members!

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Check out our episode guide at the end of the article!

The environment and our health

Since the dawn of Western medicine, we have known that climate and environment have a profound effect on our health. Nearly 2500 years ago, Hippocrates warned traveling physicians to “consider the seasons and their effects” and the implications of “winds, heat and cold” on the health of patients.

Hippocrates would not recognize the world we live in. Since the industrial era, we have invaded the natural environment. We have emitted so many tons of polluting gases that we have shrunk the stratosphere.   The Earth’s average temperature is rising rapidly and so many glaciers have melted that we have changed the planet’s axis of rotation.

Today, 75% of the Earth’s environment has been severely altered by human action. The most affected have been the million species of plants, animals and other life forms that are now threatened with extinction. Or so we thought.

In 2020, a new virus we call COVID-19 paralyzed the world. It caused an unprecedented pandemic, with an official death toll of more than three million that continues to grow every day. And this pandemic has been the result of our destructive relationship with nature.

Planet Earth is sick and wears a mask
Planet Earth is sick and wears a mask. A still from Green Generation’s Zoonosis episode.

Viruses: what are they and how do they reach us?

Even in the 21st century, viruses remain a mystery to science. Halfway between the living and the inert, viruses are small infectious agents that can only multiply in living cells of animals, plants or bacteria.

Viruses, like many other microorganisms, have been with us since our earliest days. And as we have changed and evolved, so have they. But where are the viruses?

A Green Generation illustration of a science diagram showing how a virus enters the cell membrane.
A virus enters a cell, an illustration of how infection works. A still from Green Generation’s Zoonosis episode.

We think of our bodies as a collection of cells that allow us to breathe, eat and live. But this is not true: more than half of our biological matter is not human.  Our bodies are super organisms where cells, bacteria, fungi and, above all, viruses cohabit.

Right now, in your body there are more than 380 trillion viruses. But don’t panic: it’s natural and normal. Our immune systems recognize them and know how to fight them, and some can even be beneficial to our health.

There are many, many more types of viruses than there are stars in the universe.  Some only affect people, others affect certain species of plants and animals, and there are even viruses that only infect bacteria.

What is a zoonosis?

In 2014, a little boy was playing near a hollow tree in his small village in Guinea. Suddenly he got sick, his fever spiked and he started vomiting. Two days later he died.

The tree where he was playing was infested with fruit bats, a species native to West Africa. These nocturnal animals usually live deep in forests and savannahs, as they seek dark, damp places to roost during the day.

However, these bats were far from their natural habitat. Several foreign companies were mining and logging in the Guinean rainforest. The region was subject to extreme deforestation: these foreign companies had destroyed 80% of the bats’ natural habitat.

That is why this colony of bats had settled far away from their native habitat, in a village near what was once forest. Upon contact with a child, the Ebola, a virus naturally carried by bats, infected a human for the first time since 1976.   The result was the Ebola outbreak, a health crisis that stretched into 2016, claiming the lives of more than 11,000 people.

Ebola, like the 60% of known infectious diseases including HIV and COVID-19, is the result of a zoonosis. In other words, it is a virus of animal origin that by infecting a person has become a new disease.

An illustration depicting how wildlife virus can be transmitted to humans. A bat sneezes into a person's face.
Zoonoses occur when wild animals have contact with humans. A still from Green Generation’s Zoonosis episode.

Reservoirs and wild animals

Some animals, such as bats, are reservoirs of viruses. That is, they are animals where viruses can live and survive for long periods of time.  These viruses are usually harmless to bats and do not cause them any illness, but they can be very dangerous if transmitted to a person.

A zoonosis is a matter of probability. For a virus to jump to a person, the animal carrying it must have direct contact with humans. This could be a hunter selling a wild animal at a market, a child playing near a tree or a mosquito bite.

The closer humans are to these wild animals, the more likely it is that they will interact and that a virus could jump out and infect humans. The only thing that separates such potentially infectious wildlife from us is nature’s biodiversity. The forests and jungles that are home to bats and other species should be as extensive and varied as possible, because the more life they harbor in a larger space, the farther those viruses will be from us humans.

Zoonosis are a matter of probability. A still from Green Generation's Zoonoses episode
Zoonosis are a matter of probability. A still from Green Generation’s Zoonosis episode

Protecting nature as a defense against zoonoses

Zoonoses such as Ebola or COVID-19 are an unexpected result of deforestation.  One of the areas of the planet most affected by deforestation is the tropics. The tropical forests of Africa, Asia and South America, despite occupying only 7% of the earth, are home to more than half of the planet’s species, and with them, many unknown viruses.   The COVID-19 pandemic, which emerged in Asia, was possibly a consequence of the accelerated deforestation of the continent.

Since 1990, human action has destroyed more than 80 million hectares of forest. Most of that land has been converted to agriculture operations, such as macro-farms and monoculture soybean and palm oil plantations.   It has also been used to build roads and cities, bringing large groups of people closer to the homes of wild animals and increasing the risk of a new zoonosis.

A machine cutting down the rainforest. Deforestation illustration by Green Generation, the animation series about the environment for kids. Science educational videos, only on Patreon.
Deforestation endangers us all. A machine clears the rainforest, wiping out countless animals and plants. A still from the Green Generation’s Zoonosis episode.

At the onset of the COVID-19 pandemic, UN Environment chief Inger Anderson said that “nature is sending us a message with the coronavirus pandemic”.  Despite knowing the link between the destruction of forests and the emergence of new diseases, deforestation has increased in 2020. In one year, we have lost 42,000 km2 of rainforest, the same area as the Netherlands.

If we want to avoid new diseases and pandemics, such as COVID-19, prevention is better (and cheaper) than curing. If we know that protecting our forests and their biodiversity reduces the risk of new pandemics, why don’t we start protecting nature and the biodiversity that lives in it? Which will be better in the long run, preserving the environment and forgoing overgrowth or hoping that the next pandemic will be easier to stop?

Guide to Green Generation’s Zoonosis episode

We have prepared this small complementary guide to facilitate and encourage mothers, fathers and educators to talk about zoonoses and the importance of preserving nature and its biodiversity with children. This small section complements the second episode of Green Generation, Zoonosis. You can check out our first episode, the Climate Crisis, for free in our blog.

How can we explain what zoonosis is to children?

A good way to introduce this conversation is to start from what they already know, such as the COVID-19 pandemic that we explained in the chapter.

Facts and thoughts on zoonoses

  • “Some diseases are infectious, that means they pass from one person to another.” When someone yawns in front of you, don’t you just want to yawn too? Some diseases are infectious and can pass from one person to another like a yawn. Wild animals can carry diseases that can infect us, so it’s best to stay as far away from them as possible. And in case of pandemics, such as the one we have experienced with COVID-19, it is necessary to clean our hands and always wear a mask.
  • “When we destroy nature, we also destroy the barrier that separates us from infected animals.” This year we have all put on masks to protect ourselves from COVID-19. Nature works as our mask: having a healthy forest far from our cities protects us as a barrier from diseases that other animals may have. Here is a report from Scientific American that explains how stopping deforestation helps us to prevent pandemics.
Green Generation Generacion Verde Generació Verda animación animation science for kids educación educational pandemic illustration medi ambient medio ambiente environmental
A healthcare professional wearing a Personal Protective Equipment (PPE). A still from the Green Generation’s Zoonosis episode.

Three activities to do with the family and protect nature

  1. Why don’t you all become biologists for a day? One of the best ways to appreciate biodiversity is to observe it. Next time you go to the mountains or on a nature hike, take a notebook and write down how many trees, plants, animals and insects you see. You can count individuals as well as species. If you want, you can take a picture of them and then look for the species. Here is a template for your scientific studies.
  2. Plant native plants to help local biodiversity. Did you know that thanks to bees and other pollinators we can eat strawberries, oranges and many other foods? However, there are fewer and fewer bees because their habitat, wildflowers, are disappearing due to our land use.  Plants that naturally grow in your area can help support local ecosystems by attracting bees and other pollinators, so why not take advantage of your balcony or garden? If you are in the USA, you can find the best native plants to attract bees and butterflies on this website. If you don’t have space to plant any flowers, an alternative is to participate in some reforestation in your area.
  3. Visit your local market as a family. Another way to protect local biodiversity is to support small, sustainable producers in your area. A trip to your local or sustainable market can help children understand which crops are traditionally grown close to home and which are in season. You can also talk about the carbon footprint and how eating food grown close to home helps reduce our emissions and protect the planet, as The Independent reports.

Resources we recommend

Plantnet: an app available on IOS and Android that allows you to identify the species of plants you come across. Simply take a photo, select whether it is a flower, tree, leaf or fruit and you will soon be able to identify its species.

Fernando Valladares. A CSIC biologist and university professor, Valladares is an expert in ecology and the climate crisis. He regularly publishes very interesting articles and publications detailing the latest scientific research on the climate crisis. Recently, he has been awarded the Rei Jaume I Award, one of the most prestigious spanish scientific prizes, for his work in environmental protection.


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