To avoid the next pandemic, we may need to cut fewer trees

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Reducing tropical deforestation and limiting wildlife trade could be cost-effective ways to stop pandemics before they start, new analysis says.

About once every two years, a virus passes from animals to humans, raising the specter of a pandemic like COVID-19. These “contagion events” are becoming more and more common as humans encroach more on the natural world and are responsible for some of the worst epidemics in recent memory, including SARS, Ebola, HIV and possibly the new coronavirus too.

The explosion of a pandemic spread depends on many factors, including the qualities of the virus itself and how humans respond to it. But some biologists argue that pandemic preparedness should start by reducing the likelihood of contagion events, tackling deforestation, monitoring farm animals and limiting the wildlife trade.

Such interventions would cost around $ 20 billion to $ 30 billion annually, according to analysis released on July 24. Science. This price is paltry compared to the estimated global cost of COVID-19, which exceeds US $ 5 trillion in lost gross domestic product this year alone.

“COVID has killed hundreds of thousands of people and caused massive disruption to the economy,” says co-author Stuart Pimm, conservation biologist at Duke University. “We have shown that there are a lot of smart and relatively inexpensive things we can do now to reduce the risk of another disaster like this.”

Forest edges represent a major front line for overflow events. As humans clear swaths of forest for agriculture or roads, forest edges multiply, increasing the risk of once-isolated wildlife overflowing onto humans and livestock. As this loss of forest accelerates in many places, some countries have taken action. From 2005 to 2012, Brazil implemented land use zoning and paid people not to cut down forests, reducing deforestation by 70 percent.

Based on the costs of these and other similar programs, researchers estimate that deforestation rates could be halved globally with investments of $ 1.5 billion to $ 9.5 billion per year, reducing the risks contagion while preserving biodiversity and reducing carbon emissions.

Wildlife markets and the illegal wildlife trade also bring humans into contact with wildlife and their viruses. The United States is a major market for exotic and sometimes endangered pets shipped from around the world, increasing human exposure to wildlife (SN: 14/09/18). In China, animal husbandry is a nearly $ 20 billion industry that supports cultural food preferences, but may also increase the risk of contagion events. For example, SARS probably appeared in a Chinese wildlife market.

But ending China’s wild meat trade alone would cost far more than halving deforestation. Researchers suggest it would cost around $ 19 billion a year to counter potential profits from the lucrative wild meat market. Surveillance programs that could find viruses in wildlife in potential hot spots would cost an additional $ 120 million to $ 340 million per year. In China, the government banned the trade and consumption of wildlife in February, although the details and long-term outlook for the ban remain uncertain.

Pimm and his colleagues estimate that other interventions, such as virus surveillance in cattle, would cost hundreds of millions of dollars each year.


Weighing costs

This table shows a breakdown of the estimated annual costs of various measures to reduce the likelihood of contagion events, where animal viruses spread to humans, compared to the estimated global gross domestic product lost this year due to the COVID-pandemic. 19.

Cost of COVID-19 vs. Maximum Annual Costs of Pandemic Prevention Measures
Global GDP drop in 2020 due to COVID-19 5,6 billions de dollars
Total maximum prevention costs $ 31.2 billion
Ending China’s wild meat trade $ 19.4 billion
Halve deforestation $ 9.59 billion
Limit the fallout from livestock $ 852 million
Limit the fallout from wildlife $ 340 million
Early detection of disease $ 279 million
Monitor wildlife trade $ 750 million

Source: AP Dobson et al / Science 2020


To justify these costs, interventions would have to reduce the risk of a pandemic by 27% in any given year, according to the analysis.

It is difficult to determine exactly how well these interventions reduce the risk of fallout, Pimm says. “We are not going to stop [spillover events], but we’ve shown that while these interventions make pandemics less likely in no time, it’s a cost-effective solution. ”

“It’s great to have more evidence on the stack as to why pandemic prevention is important and why it pays off,” says Colin Carlson, global change biologist at Georgetown University in Washington, DC, who did not participate in the study. But he fears that focusing on reducing contagion effects could harm much-needed investments in public health infrastructure.

“Deforestation and the wildlife trade cause a fallout, but it does not cause a pandemic,” he said, noting that reducing these activities can reduce the risk of a pandemic. “Pandemics arise because of a lack of governance, sensible public health interventions and surveillance.”

Carlson is particularly skeptical of the profitability of ending the wildlife trade. “The idea that we would spend two to ten times as much to end the wildlife trade in a country than we would spend to halve global deforestation should tell us where the easy solutions lie,” he says. Efforts to reduce the consumption of wild meat in response to disease outbreaks can also harm local populations who depend on wild meat for protein and diminish confidence in public health, which happened during the 2015 Ebola outbreak.

While the wildlife trade is a source of spinoff, Carlson says the focus on it often exceeds the evidence. Despite many suggestions that the coronavirus originated from a wildlife market in Wuhan, this link is not yet widely accepted.

Pimm and his colleagues agree that controlling the wild meat trade should take into account local needs and that some of the interventions they propose are probably more cost-effective than others. “But these actions would be a prudent investment for national and international security,” Pimm says. “And nothing we offer is expensive compared to countries’ military spending for security.”

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