Land-use change related to forest fragmentation, agricultural expansion and concentrated livestock production are creating favourable ‘hot spots’ globally for bats carrying coronavirus and conditions for animal to human transmissions, according to a new study.
The study published by researchers at the University of California, Berkeley, the Politecnico di Milano (Polytechnic University of Milan) and the Massey University of New Zealand used remote sensors to analyze land-use patterns of horseshoe bats, identified early on as the probable origin of Covid-19.
While bats have been zeroed on as the prime origin of the SARS-CoV-2 virus, scientists believe the virus would have passed from the winged mammals to another species before reaching humans. Experts had identified pangolin as a suspect as it is one of the animals sold in the market in China’s Wuhan, as the city is known to have reported one of the first known coronavirus cases. The theory was studied in a joint investigation by World Health Organization (WHO) experts and Chinese scientists who visited Wuhan in January 2021. However, no new findings of this missing link were found.
The new study examined forest fragmentation, human settlement and agricultural and livestock production and comparison with the horseshoe bat’s habitats to identify potential hotspots where man-animal transmission or zoonotic pathogen could be contracted.
“Land use changes can have an important impact on human health, both because we are modifying the environment, but also because they can increase our exposure to zoonotic disease,” said study co-author Paolo D’Odorico, a professor of environmental science, policy and management at UC Berkeley.
The study found China has most of the current hotspots where a growing demand for meat products has driven large-scale, industrial livestock farming. Researchers noted that concentrated livestock production is concerning as the practice brings together large populations of genetically similar, often immune-suppressed animals, increasing the risk for disease outbreaks.
Parts of Japan, the north Philippines and China south of Shanghai are at risk of becoming emerging hotspots due to forest fragmentation and some Indo-china and Thailand regions due to increased livestock production.
While horseshoe bats are generalist species, meaning they can survive in many different habitats, they are often been observed in areas characterized by human disturbance, researchers said. Earlier work by Rulli, D’Odorico and study co-author David Hayman have linked forest fragmentation and habitat destruction in Africa to outbreaks of the Ebola virus.
“By creating conditions that are disadvantageous to specialist species, generalist species can thrive,” 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.”