BENGALURU: A recent study has revealed that the global ‘hotspots’ where the new deadly coronaviruses may emerge, driven by global changes in land use by humans. While China tops the list, the study mentions India’s Kerala and North-East states as vulnerable hotspots. The study ‘Land-use change and the livestock revolution increase the risk of zoonotic coronavirus transmission from Rhinolophid bats’, conducted by researchers at the University of California, Berkeley, the Politecnico di Milano (Polytechnic University of Milan) and the Massey University of New Zealand, was published in Nature Food.
According to the study, forest fragmentation, agricultural expansion and livestock production are all bringing humans into closer contact with horseshoe bats, which are known to carry zoonotic diseases, including Covid-19. “Conditions are ‘ripe’ for the diseases to jump from bats to humans, particularly in China, where a growing demand for meat products has driven expansion of large-scale, industrial livestock farming,” the study stated.Concentrated livestock production is a cause of concern because it brings together large populations of genetically similar, often immune-suppressed animals that are highly vulnerable to disease outbreaks, the researchers said.
“The other major global hotspots outside China are in Java, Bhutan, east Nepal, northern Bangladesh, the state of Kerala (India) and northeast India,” according to the researchers. While there are also low risk ‘coldspots’ in southern China, the analysis also found that parts of the country south of Shanghai, as well as Japan and the north Philippines, are at risk of becoming hotspots with further forest fragmentation. Meanwhile, parts of Mainland Southeast Asia (Indochina) and Thailand may transition into hot spots with increases in livestock production, the study said.
They used remote sensing to analyse land use patterns throughout the horseshoe bat’s range, which extends from Western Europe through Southeast Asia. The team identified areas of forest fragmentation, human settlement and agricultural and livestock production, which they compared to known horseshoe bat habitats. This allowed them to find the potential hotspots where habitat is favourable for these bat species in the horseshoe family (Rhinolophidae), and where zoonotic viruses could jump from bats to humans. “We hope these results could be useful for identifying region-specific targeted interventions needed to increase resilience to coronavirus spillovers,” said study co-author Maria Cristina Rulli at Polytechnic University of Milan.
Agreeing that increase in livestock production and forest fragmentation has indeed brought humans closer to zoonotic diseases, Dr Jacob John, virologist and former professor, Christian Medical College, Vellore, said, “Among all the vertebrates in the world, rodents and bats carry a lot of viruses that humans must be very careful about. These bats are carriers of coronaviruses like SARS-COV2, MERS and CoV Ebola. The Nipah virus is a classic example. India has had Nipah virus in West Bengal and Kerala which means all of India is vulnerable. If somewhere in India it happens then it will affect everywhere.”
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He also said that it is almost impossible to predict where bat viruses can transfer to humans. But one can say that wherever bats are not present then the risk of such virus is less. “Maharshtra, Kerala, Tamil Nadu, North Eastern states are all tropical and sub-tropical places for bats,” he said.Calling this a seminal paper, Dr Vishal Rao, Dean of the Centre for Academics Research, HCG Cancer Centre, said that this comes as a forewarning to policy makers showing the extent to which humans facilitate zoonotic transmission of infectious diseases. “Human encroachment into wildlife habitats with expanding urbanization, cropland area and intensive animal farming will need to be replanned in a more careful and ecologically balanced manner to prevent the emergence of zoonotic diseases,” Dr Rao said.