Researchers say that the more we destroy animal habitat the more we become vulnerable to viruses. Viruses and bacteria usually come from animals, as is the case with Covid-19, which originated in the ‘wet markets’ of Wuhan in China in late 2019. From a ‘zoonotic’ origin, the virus has spread among humans. A 2020 study explored the link between the abundance of species that carry such zoonotic viruses and the likelihood of spillover to humans. Searching through scientific literature, they obtained data on 142 zoonotic viruses and found that rodents, primates, and bats carried more of these viruses than other species.
Researches done by the National Geographic, in collaboration with San Diego State University, reveal that the biodiversity of nature need to be left intact for the very survival of the human species. We have turned wild habitats into cities, farmlands and shopping malls. The more we encroach upon the wild habitat and compete with animals for water, food and territory, there is bound to be more physical contact, yielding more man-animal conflict, and consequently more pandemics. The more we degrade the animal habitats, the animals get stressed and shed more viruses.
Working in some virgin Pacific Islands, the scientists were assessing the diversity of everything – viruses, bacteria. algae, invertebrates and fish. Their primary intention was to measure how the coral reef ecosystem changed with human disturbance. When the humans start fishing, they trim the food web from the top. They found that the coral reef shifts from one with lots of sharks and corals to one without sharks but with lots of small fish and seaweed. The number of microbes in water increased with the presence of humans. They found that a third of the microbial bacteria were pathogens like several types of staphylococcus, vibrio and escherichia. The pathogen vibrio can cause fatal diseases in humans such as cholera, gastroenteritis and septicemia. The scientists described this shift in the ecosystem – from mature stable and full of large animals to immature and dominated by small creatures – as ‘microbialisation’ of coral reefs. They also discovered that the ‘giants clams’ which were in plenty in pristine surroundings –and reduced in human presence – removed most viruses and bacteria, including vibrio, from seawater. In other words, nature controls viruses, filtering them out of the systems. People have unknowingly been removing the natural filters – the N95 masks – of the place that protect against viral diseases. Biodiversity dilutes any viruses that emerge and provides a natural shield that absorbs the fallout from pathogens.
That China is highly prone to viral attacks is clear from the fact that it has removed almost all its forests and has given orders to remove all the tigers to make way for human habitation. It is true that China suffers from tremendous demographic pressures; but with the proven fact that most of these viral epidemics originate from China, the world has to wake up to the consequences of clearing forestlands. Clamping down on illegal trade of wildlife, ending deforestation, protecting intact ecosystems, educating people about risks of consuming wildlife, changing the way we produce food, phasing out fossil fuels : these are the things we must do for our survival.
Now more than ever we need the wild. Healthy natural world is our best option.