In Gun Island, Amitav Ghosh’s climate change novel, a yellow-bellied sea snake bites and kills a dog in Venice Beach, Los Angeles, far from the natural habitat of this venomous reptile. The novel coronavirus, which has hobbled the world’s health infrastructure and has snuffed out thousands of lives often in deadly cytokine storms, has most likely spilled over from a bat population in China via an intermediate pangolin host. However unrelated these two events may seem they have but one definite connection—the invisible hand of Homo sapiens.
Right from the days of the Industrial Revolution and even earlier, our species has been increasingly exploiting the resources of the planet, poisoning its air and sullying its seas. The age of the Anthropocene is marked by the hydra-headed problem of climate change with its tipping points and feedback mechanisms. It has also cemented our role in certain disease outbreaks and transmission, topped by the current pandemic. The situation has now turned so dire that completely unacceptable views like ‘Corona is the cure, humans are the disease’ are widely circulated in the social media space.
About 60 years ago in the Kyasanur forest of Karnataka’s Western Ghats, unexplained discoveries of dead black-faced langurs and an outbreak of haemorrhagic fever among villagers led zoologist PK Rajagopalan on to the tracks of a deadly tick-borne flavivirus, which causes the mysterious Kyasanur Forest Disease (KFD) in humans. Clearing of forests, associated biodiversity loss and a coming together of favourable conditions described as ‘Boshell’s cup of coffee’ after a Colombian epidemiologist, have been implicated in so-called ‘spillover’ events where viruses leap across species barriers.
When we were college students, dengue was largely a forgotten illness. Today, the dengue virus, which is transmitted by the Aedes aegypti mosquito, is back with vengeance. Researchers agree that climate change will increase the risk and disease burden of viruses transmitted by this particular dark-coloured bloodsucking pest. The diseases in question—dengue, chikungunya and Zika—have no specific cure. Obviously our impact on biodiversity and ecosystems, destruction of habitats and actions aggravating climate change are having serious impacts on the living planet and human health.
Speaking of the Covid-19 pandemic, Jem Bendell of the University of Cumbria recently pointed out the possibility that bats, the natural reservoirs for the virus, may have changed their movements because of warmer habitats, coming closer to humans in the process. Which reminds us of Barbara Kingsolver’s cli-fi novel, Flight Behaviour, where monarch butterflies alter their migration routes because of climate change.
The wet markets for exotic species in China and East Asia, and the bush meat stalls in some regions of Africa present us with stomach-churning visuals. These are also possible locations of spillover events in which diseases of the wild infect humans which then, because of increasing international travel, can spread. A combination of policies, including strong implementation of international conventions and domestic laws against trade in wild species, provision of alternative sustainable nutrition coupled with stakeholder awareness, could be useful in closing down these sources of outbreaks.
It is estimated that about 60 percent of emerging pathogens in humans are zoonotic—of animal origin, and 70 percent of these come from the wild. Of these are feared diseases like Ebola, MERS, SARS and many others. Dangerous viruses, which were quietly circulating in the wild, have been increasingly coming in contact with people because of rapid urbanisation, plundering of forest resources, monoculture, road construction, displacement of virus hosts by climate change and because of overconsumption and unsustainable development. India with its biodiversity hotspots, which are under stress from a rapidly growing free market economy and high population density, seems poised for a perfect storm of a zoonotic outbreak.
As the links between human activity and animal-borne illness become clear, there are increasing calls for addressing health and environment issues together and not separately. Mridula Mary Paul, a Senior Policy Analyst at the Ashoka Trust for Research in Ecology and the Environment (ATREE), Bengaluru, says, “There should definitely be more concerted efforts to recognise the strong links between environment and health, and to adopt the multi-sectoral OneHealth approach to understanding and managing zoonotic infectious disease risk in India. This begins with strengthening our existing environment protection laws, as well as the overall public health infrastructure.’ The sooner we recognise this, the better will it be for people and the planet.
Twitter @rajatchaudhuri