[News] Study suggests that climate change could drive the emergence of COVID-19

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A new study, published in the journal Science of the Total Environment, provides the first evidence of a mechanism by which climate change may have played a direct role in the emergence of SARS-CoV-2, the virus that causes the COVID pandemic. -19.

Global greenhouse gas emissions over the past century have made southern China a hotspot for bat-borne coronaviruses, fueling the growth of bat-favored forest habitat.

The study has revealed large-scale changes in vegetation type in Yunnan province in southern China and adjacent regions in Myanmar and Laos over the past century.

Climate changes, including increases in temperature, sunlight, and atmospheric carbon dioxide, which affect the growth of plants and trees, have changed natural habitats from tropical scrub to tropical savannas and deciduous forests. This created a suitable environment for many species of bats that predominantly live in forests.

The amount of coronavirus in an area is closely related to the number of different species of bats present. The study found that another 40 species of bats have moved to Yunnan Province in southern China in the past century, harboring around 100 more types of bat-borne coronavirus. This 'global hotspot' is the region where genetic data suggest that SARS-CoV-2 may have emerged.

"Climate change over the last century has made the habitat in southern China's Yunnan Province suitable for more species of bats," says Dr Robert Beyer, a researcher in the Department of Zoology at the University of Cambridge , in the United Kingdom, and first author of the study, who recently won a European research grant at the Potsdam Institute for Climate Impact Research in Germany.

"Understanding how the global distribution of bat species has changed as a result of climate change can be an important step in reconstructing the origin of the COVID-19 outbreak," he highlights.

To obtain their results, the researchers created a map of the world's vegetation as it was a century ago, using records of temperature, precipitation and cloud cover. They then used information about the vegetation requirements of the world's bat species to calculate the global distribution of each species in the early 20th century.

Comparing this to current distributions allowed them to see how the 'species richness' of bats, the number of different species, has changed around the world over the last century due to climate change.

"When climate change altered habitats, species left some areas and moved to others, taking their viruses," Beyer explains. "This not only altered the regions where viruses are present, but most likely allowed new ones. interactions between animals and viruses, causing more harmful viruses to be transmitted or evolved. "

The world's bat po[CENSORED]tion carries around 3,000 different types of coronavirus, and each bat species harbors an average of 2.7 coronaviruses, most showing no symptoms. An increase in the number of bat species in a particular region, driven by climate change, can increase the likelihood that a coronavirus harmful to humans is present, transmitted or evolved there.

Most bat-borne coronaviruses cannot affect humans. But it is highly likely that several coronaviruses known to infect humans have originated in bats, including three that can cause human deaths: Middle East respiratory syndrome (MERS) CoV and severe acute respiratory syndrome (SARS) CoV- 1 and CoV-2.

The region identified by the study as a hotspot for a climate-driven increase in bat species richness is also home to pangolins, which are suggested to have acted as intermediate hosts for SARS-CoV-2. The virus likely passed from bats to these animals, which were later sold at a wildlife market in Wuhan, where the initial human outbreak occurred.

The researchers echo calls from previous studies urging policy makers to recognize the role of climate change in viral disease outbreaks and to address climate change as part of COVID-19 economic recovery programs.

"The COVID-19 pandemic has caused tremendous social and economic damage. Governments must seize the opportunity to reduce the health risks of infectious diseases by taking decisive action to mitigate climate change," explains Professor Andrea Manica, from the Department of Zoology, University of Cambridge, who participated in the study.

"The fact that climate change can accelerate the transmission of pathogens from wildlife to humans should be an urgent wake-up call to reduce global emissions," adds Professor Camilo Mora of the University of Hawaii, who initiated the draft.

The researchers highlight the need to limit the expansion of urban areas, farmland and hunting grounds into natural habitats to reduce contact between humans and disease-carrying animals.

The study also shows that over the last century, climate change has also led to increases in the number of bat species in regions of Central Africa and scattered patches in Central and South America.