Areas in China could "very likely" spark another deadly pandemic as humans encroach on bat territory, a study has found.
A cluster of "hot spots" that inhabit bats carrying coronaviruses have been identified, where conditions are ripe for diseases to transmit from the animal to humans.
The study published in Nature by researchers at University of California, Berkeley, Polytechnic University of Milan and Massey University of New Zealand said that Covid likely emerged when a virus infecting horseshoe bats jumped to humans.
Scientists believe it could have occurred either through wildlife-to-human contact, or by first transmitting to an intermediate animal host.
The study said the new hotspots were identified after researchers pinpointed areas of forest fragmentation, human settlement and agricultural livestock production.
"Comparing these to known horseshoe bat habitats, they identified potential hotspots where habitat is favourable for these bat species, and where these so-called zoonotic viruses could potentially jump from bats to humans," a statement from UC Berkeley said.
Professor of environmental science, policy and management at the university, Paolo D'Odorico, said changes in land use could impact on human health.
"Every formal land use change should be evaluated not only for the environmental and social impacts on resources such as carbon stocks, microclimate and water availability, but also for the potential chain reactions that could impact human health," he said.
Hotspots clustered in China
According to the study, the hotspots are mainly clustered in China as there is more industrial livestock farming taking place due to a growing demand for meat products.
There are concerns over concentrated livestock production because with it comes large populations of genetically similar, often immune-suppressed animals that are more vulnerable to outbreaks of diseases.
The study also found there were many parts of China south of Shanghai at risk of becoming danger zones because of forest fragmentation, along with areas in Japan and the north Philippines.
Some parts of Indochina, east of India and southwest of China, and Thailand could be added to the list of hotspots if they increase livestock production.
“The analyses aimed to identify the possible emergence of new hotspots in response to an increase in one of three land use attributes, highlighting both the areas that could become suitable for spillover, and the type of land use change that could induce hotspot activation,” study co-author Maria Cristina Rulli, a professor in hydrology and water and food security at the Politecnico di Milano in Italy, said.
“We hope these results could be useful for identifying region-specific targeted interventions needed to increase resilience to coronavirus spillovers.”
A study in 2017 also found forest fragmentation and habitat destruction in Africa led to Ebola virus outbreaks.
Changes in land use lead to bat and human contact
When humans take over an animal's natural habitat "specialist species" that need certain conditions could become extinct.
However "generalist species", like the horseshoe bat, is less picky.
“By creating conditions that are disadvantageous to specialist species, generalist species are able to thrive,” Professor D’Odorico said.
“While we are unable to directly trace the transmission of SARS-CoV-2 from wildlife to humans, we do know that the type of land use change that brings humans into the picture is typically associated with the presence of these bats who are known to carry the virus.
“Our study is one of the first to connect the dots and really drill down into the geographic data on land use to see how humans are coming into contact with species that might be carriers.”
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