The unsustainable exploitation of the soil and forests brings man closer to the animal reservoirs of coronavirus: here is the map of the areas most at risk.
To explain the origin of CoViD-19, by now we know , it is not necessary to bother with improbable theories on a possible escape of pathogens from biosecurity laboratories: it is sufficient to objectively analyze the increasingly unbalanced relationship between man and natural habitats. A new study published in Nature Food takes a small step further and traces, in a series of maps, the “hot spots” where future coronavirus pandemics could emerge.
DANGEROUS ENCOUNTERS. A group of scientists composed of Maria Cristina Rulli and Nikolas Galli of the Politecnico di Milano, Paolo D’Odorico of the University of California at Berkeley (United States) and David Hayman of Massey University (New Zealand) crossed the data on the less sustainable forms of exploitation of the soil by humans with those on the distribution of animal reservoirs of coronavirus, to find the present and future hotspots (“hot spots”) of other potential highly contagious zoonoses.
THE COVID, AT THE BEGINNING. The most accredited theory on the origin of SARS-CoV-2 has it that the covid coronavirus was transmitted, to humans or an intermediate species, by horseshoe bats ( Rhinolophus affinis ): in those found in the province of Yunnan , in China, was in fact isolated the genome of the next of kin to us known virus CoViD-19, the coronavirus RaTG13, which has a genetic profile for the 96.2% identical to the pathogen of the current pandemic.
As Rhinolophus often hosts coronaviruses, many of them yet to be discovered, the researchers thought of identifying the areas in which the probability of interaction between these animals and humans is highest, analyzing land use in 10,000 areas of Europe and Asia. To do this, they used high-resolution satellite data.
ScienceInvestigations into the progenitor of SARS-CoV-2
OUR FAULT. In fact, human activities, and certainly not the simple presence of bats in the habitat, determine the risk of the passage of viruses from animals to humans ( spillover ). For example, the advance of human settlements in areas once occupied by forests increases the opportunities for contact with the animals that host the pathogens; the growth of factory farms provides coronaviruses with a wide range of potential intermediate, immunosuppressed and compacted animal hosts; forest fragmentation reduces specialist animal species (i.e. which have limited ecological niches) and increases the spread and movement capacity of generalist ones, with ample adaptability, such as horseshoe bats.
The areas that risk hosting future spillovers (in red), and the causes: habitat fragmentation (green), human settlements (purple), intensive farming (pink). © Rulli et al, 2021, Nature Food
WHERE TO LOOK? Analyzing the prevalence of habitat-deleterious behaviors, such as deforestation and forest fragmentation due to the expansion of cultivated land, the density of livestock farms or the presence of human settlements in regions populated by horseshoe bats – a greater total area 28.5 million square km from Western Europe to East Asia – the team mapped the spots where new coronavirus pandemics could arise today or in the future. Most of the current hotspots are in China, where a growing demand for food of animal origin has led to the expansion of large-scale industrial farming, and where there is a high density of population and forest fragmentation. with human settlements.
But if you look at how land use is changing and look to the future, you see that many areas outside of China, such as Japan and the northern Philippines, are vulnerable to forest fragmentation, or parts of the country. Southeast Asia, largely dedicated to animal breeding, could be the site of possible future spillovers. «Human health», the scientists recall, «is connected with environmental health and also with animal health».