Sunday, 21 March 2021

the spread of zoonotic diseases

For the last year, questions have been asked about the origin of Covid:

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In June, from Marco Lambertini, director-general of WWF International:

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Coronavirus is a warning to us to mend our broken relationship with nature

In 1997, a large area of rainforest in south-east Asia was burned to the ground to make way for palm oil plantations. A combination of deforestation, forest fires and drought are believed to have forced hundreds of fruit bats away from their natural habitats towards fruit orchards planted in close proximity to intensive pig farms. These conditions led to the emergence of the Nipah virus, which spilled over from infected bats to pigs, and from pigs to pig farmers. Over the next two years, the disease would kill more than 100 people. This should have served as a warning.

Now, 20 years later, we are facing a health crisis of an altogether different scale, with Covid-19 causing the most tragic health, social and economic crisis in living memory.

We have seen many diseases emerge over the years – such as Zika, Aids, Sars and Ebola – and although they are quite different at first glance, they all originated from animal populations under conditions of severe environmental pressures. And they all illustrate that our destructive behaviour towards nature is endangering our own health – a stark reality we’ve been collectively ignoring for decades. Research indicates that most emerging infectious diseases are driven by human activities…

Considerably strengthening and enforcing regulation, enhancing food safety, ending the illegal and unsustainable wildlife trade, and providing alternative livelihood options to reduce the consumption of wildlife everywhere are critical steps to help prevent future zoonotic diseases from emerging.

Coronavirus is a warning to us to mend our broken relationship with nature | Environment | The Guardian

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In October, from Tim Benton, Research Director of emerging risks at Chatham House:

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Failure to reset our relationship with nature may lead to more frequent pandemics

In the last decades, we have seen a range of new or emerging infectious diseases, which have jumped to humans from animals. HIV/AIDs came from great apes, birds gave us H5N1 (causing the 2004-7 Bird Flu pandemic), pigs gave us the Swine Flu (H1N1); and SARS came from bats, via civets. Bats also gave us Ebola, and probably COVID-19. COVID-19 has now caused over a million deaths worldwide, and its implications for human health and wellbeing are devastating. COVID-19 is, however, more than a ‘health issue’, and more than an economic one; its emergence was an evolutionary and ecological issue, and a predictable consequence of species brought into new and close contact…

COVID-19 and ecology

Emerging diseases are a symptom of disrupted ecologies and new animal-animal and animal-human exposure. This is happening for three main reasons…

Failure to reset our relationship with nature may lead to more frequent pandemics

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And this week on BBC Radio 4, from Chris van Tulleken, who explores the human behaviours causing pandemics, paying the price for getting too close to animals by degrading their territory and allowing viruses to jump:

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The Jump: Covid-19

What’s clear is that Covid-19 was inevitable; that a coronavirus would jump in Asia was predicted in at least 3 papers in early 2019. It’s a symptom of degraded ecosystems leading to intimate contact with animals we don’t normally encounter.

When examining the origins of Covid-19, perhaps the most amazing aspect is the number of different possibilities. Bats as medicine, bats as food, bat transmission to other intermediate animals – mink farmed for fur or raccoon dogs hunted as game. We don’t know if it jumped in a home or a wet market or in a cave.

Chris talks to NERVTAG virologist Prof Wendy Barclay who explains why she thinks it’s not the case that it escaped from a lab.

Plus ecologist and bat enthusiast Prof Kate Jones argues that invasive human behaviours are offering these viruses multiple chances to jump into people – mostly all totally hidden from sight – but is optimistic as the UK Government asks her to advise on spillover risks and how to achieve sustainable landscapes.

While Dr Peter Daszak and Dr William Karesh from EcoHealth Alliance highlight how climate change and pandemic risk are interconnected; all the solutions already identified to tackle global warming will also help prevent the next virus from jumping.

BBC Radio 4 – The Jump, The Jump: Covid-19

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