「… では、どうして工場的規模で飼育されている家畜が動物由来感染症と関係するのでしょう? 密飼いの家畜がウィルスの媒介源になるのです。
作家・サイエンスジャーナリスト2013年に出版した“Spillover: Animal infections and the next human pandemic.”で、新型コロナを予見したとして注目を浴びる。
“The connections between ecological destruction, pandemics and the food we eat”David QuammenThe health of the planet and the people@ Slow Food Event “Terra Madre Salone Del Gusto” 2021年2月開催
“The connections between ecological destruction, pandemics and the food we eat”
Hello, this is David Quammen.
I’m an author and science journalist. My books include “Spillover: Animal infections and the next human pandemic.” I’m very grateful to Terra Madre Salone Del Gusto for the opportunity to talk with you today.
What I want to talk with you about is the connections between viruses, ecological disruption, the threat of human pandemic and the food we all eat. Those connections are very important. All of the choices that we make as individuals and as communities have consequences. Those consequences include the health of animals, the health of ecosystems and human health. Now that’s the concept that some scientists refer to as One Health. It’s all One Health. The health of ecosystems, the health of other animals and the health of humans on this planet.
So, I’ll start with viruses. Viruses are normal. Viruses are natural. Viruses are everywhere. We live on a planet of viruses.
Viruses are genetic parasites. They can only replicate, they can only complete their life cycles within the cells of cellular creatures. Viruses are not cellular. They can only complete their life cycles within the cells of animals, plants, fungi or other cellular creatures. And amid all of the biological diversity on this planet, all of those creatures, those animals, plants, fungi, other things that live in our great diverse ecosystems, our forests, jungles, our wetlands, our oceans. All of those creatures contain viruses. They naturally contain viruses. And they contain unique viruses. It’s not known exactly how many kinds of viruses live in each species of animal, plant and fungus. But some scientists suspect it might be as many as 10 unique viruses in any species of wild animals. So viruses are out there.
When a virus passes from a non-human animal host into a human, catches hold, causes an infection, replicates, that’s called a spillover from the non-human host into the human. If the spillover spreads and causes a dozen or two dozen cases of a new disease and a remote place that’s an outbreak. If the outbreak spreads across a country we call that an epidemic. And if the epidemic, if this viral contagion, gets to an international airport, spreads around the world, that is a pandemic.
Now why do these things happen? Why has Covid-19 happened? Why have the pandemics of the past happen? Why have these spillovers of dangerous viruses such as Ebola and Hendra and Nipah and avian influenza happened? It’s because of ecological disruption. That is at the basis of it. Humans come in contact with wild animals disturbing remote wild diverse ecosystems to capture animals for food, to take them markets alive or kill them to take out timber, to take out fossil fuels, to take out other mineral resources, we go into the tropical forest we build timber camps and mining camps and we expose ourselves to the viruses from these wild animals. And that creates an opportunity for pandemic disease. A new viruses gets into humans and spreads the way the SARS-CoV-2 virus cause of COVID-19 has spread.
Right? So the choices that we make, what we eat, what we consume in all ways, how many children we have, if we have children, the food that comes to us from factory farms. All of these choices have implications.
Now, why are domestic animals raised in factory scale for food part of this problem? Well they can be intermediate reservoirs. For instance, there is a very famous case. Nipah virus spilled over from fruit bats in northern Malaysia in 1998 got into piggeries, great factory scale pig farms in Northern Malaysia. The virus spread from pig to pig because they were being raised at such concentrations and then passed from them into humans into pig farmers, into pork dealers, into others. This is only one instance of the fact that factory-scale farming can be a circumstance that contributes to the spread, the amplification, the dispersal of dangerous viruses from wild animals ultimately into humans that can cause pandemic.
Again, one health. It’s a remainder that we are all connected. The choices that we make including the food that we eat and how that food is obtained how it is raised have implications that can lead either to a healthier planet or to pandemic disease.
So I ask you all to think about this. And I hope that you will all be well, be healthy, be safe. And I wish you a very very good 2021.