Waking up to One Health in the wake of the coronavirus pandemic: A virologist’s view
Dr Camilla Benfield, from Cambridge, a lecturer in virology, offers her perspective on the Covid-19 crisis.
“That £330 billion bailout must be the costliest pangolin dinner in history,” a friend said to me.
Immediate caveat: we don’t know that SARS-CoV-2, the causative agent of Covid-19, arose in pangolins. The scientific jury is still out on this - the whole genome of SARS-CoV-2 causing the pandemic is more similar to a bat-derived coronavirus, but the crucial host cell receptor-binding region actually shares greater similarity with a pangolin-derived virus.
Pangolins are scaly anteaters, comprising eight ancient species of mammal that originated on Earth just after the dinosaurs went extinct, and in the 21st century find themselves “the most traded wild mammals globally” according to the International Union for Conservation of Nature (IUCN).
Its meat and unusual keratin scales are both highly prized, particularly in Chinese traditional medicine. Massive population declines through poaching led to an alert in 2013 from IUCN that Chinese pangolins were critically endangered and at risk of extinction.
As many lecturers before me, I remind students that 75 per cent of newly-emerged pathogens in people have a wildlife origin.
It makes complete sense that the diverse biosphere of wild animals harbours a diverse biosphere of microbes. Other coronavirus epidemics - SARS and MERS coronaviruses - had their origins in wildlife, as does the global pandemic burden of HIV/AIDS, which resulted from cross-species transmission of a virus called SIV from other primates, likely via bushmeat-hunting linked to increased timber trade and deforestation in Central Africa.
Reconstructing virus ‘family trees’ shows that many now-endemic human viruses, including measles, respiratory syncytial virus (RSV) and other coronavirus species that cause the ‘common cold’, are intermixed with animal viruses and must have evolved from these many centuries ago.
We are an animal species that has undergone more extreme ecological transitions than any other: from our hunter-gather forebears via farming to extreme urbanisation and global connectivity. We have ‘shared’ these transitions with the microbes that share our habitat and that exist at the interfaces we have created with other animal species via domestication, utilisation and habitat encroachment.
Viruses resemble the rest of the biosphere, including Homo sapiens, in that Darwinian evolution and natural selection rules them, just as it does every other reproductive entity on the planet.
However, viruses differ from H. sapiens in having much higher evolutionary rates, which enable them readily to adapt to opportunities to infect new hosts, opportunities which we are creating in anthropogenically-altered environments.
From humble beginnings, in a pangolin/bat/other in Wuhan, SARS-CoV-2 has emerged to cause meltdown of economies and societies worldwide. We are in now in combat phase, deploying human resourcefulness to save lives and livelihoods, but we must not lose sight of prophylaxis.
Our post-Covid-19 world must adopt a more holistic approach to health in order to protect it. This approach must be less introspective and human-focused.
It must recognise, and respect, the critical interdependencies between human, animal and environmental health, and the porosity of national and species barriers to pathogens. This enables us to mitigate disease emergence and ecosystem dysfunction at the proximal stage of resource extraction and utilisation, while being sensitive to human needs and cultures. We must not vilify or persecute wildlife, knowing that they may harbour potential pathogens, but instead preserve the integrity and health of their habitats and limit encroachment.
No scientist can predict the next pandemic, even with the best surveillance data. But we know pandemics will continue to plague us, as they have over history, and that globalisation greatly magnifies their impact.
The current pandemic has exposed the fragility of our market-driven socio-economic systems.
I hope it can also jolt us - health professionals, policy-makers and wider society - into greater awareness of our place within biological ecosystems and of the fundamental bases for human health.
Dr Benfield is course director of MSc One Health: ecosystems, humans and animals at the Royal Veterinary College, University of London.
Views expressed are her own and do not reflect those of her employer.