As the coronavirus outbreak shows, zoonoses originating from wildlife pose huge public health, biosafety and even global security risks. Photo: © Eugene Troskie/Shutterstock.com

Everything is connected.

Using the theory of chaos, when a butterfly flaps its wings in New Mexico it has the power to cause a hurricane in China. But there’s hardly anything of the butterfly effect’s randomness in the dominos that keep falling after the emergence of COVID-19 (coronavirus). The explanation that is emerging is in fact more familiar: how human beings’ connected actions can result in dramatic consequences.

Wildlife and emerging infectious diseases

Although the science is not yet conclusive, one thing seems beyond doubt: the SARS-CoV-2 originated in wildlife, from where the virus managed to break the species barrier into humans. A species of Horseshoe Bat is currently the principal suspect. The bat likely transmitted the virus to an intermediary host, with an early theory pointing at pangolins, the scaly anteater illegally traded for their meat and scales which are then used for their apparent medicinal value. Human contact with the intermediary host, facilitated the final leap of the pathogen, causing a pandemic which, at the time of writing has spread to over 140 countries, infecting more than 150,000 people and causing innumerable losses.

Facilitating the emergence of new, deadly pathogens

The origin and pathway of the coronavirus pandemic shouldn’t surprise us. The SARS epidemic in 2003 jumped to humans from civet cats, sold in markets as pets and as a delicacy. MERS was transmitted to humans from camels in 2012. Avian influenza, Nipah virus, Ebola, HIV… all of these and many other Emerging Infectious Diseases (EIDs) originated in animals and were transmitted to humans – a phenomenon called zoonosis. In fact, it’s estimated that over 60% of all EID events worldwide are zoonoses, and within the zoonosis, the great majority (over 70%) originate in wildlife.

As the coronavirus outbreak shows, zoonoses originating from wildlife pose huge public health, biosafety and even global security risks.

As the coronavirus outbreak shows, zoonoses originating from wildlife pose huge public health, biosafety and even global security risks. The potential Pangolin Effect denotes the unavoidable, disproportionate ending of an avoidable, relatively modest beginning: a virus, present on a natural host in the wild, causes a pandemic by taking advantage of a large chain of interconnected events able to spread it globally.

The first, large amplification phenomenon is increased exposure. Due to anthropogenic activities, we are substantially increasing our exposure to pathogens we have never been exposed to, and thus we’re not prepared to respond to. We’re doing this in two main ways: bringing wildlife too close to us, or us getting too close to wildlife. The second, large amplification phenomenon could be attributed to globalization: once a pathogen has spilled over to humans, and enough individuals are infected, international flights and cruises and global value chains, transport those infected individuals to all corners of the globe.

Bringing wildlife too close to us: the wildlife trade

Illegal wildlife trade is estimated to be the fourth largest illegal crime in the world after drugs, counterfeits and human trafficking. The legal wildlife trade is regulated by the CITES convention, but its objective is to ensure that the trade does not threaten wildlife survival. Both types of trade act as large conveyor belts, transporting wildlife -and their pathogens- far and wide, intensifying contact with humans and significantly increasing the chances of transmission.

Illegal trade was likely the conduit through which COVID-infected animals were forced into contact with humans

Illegal trade was likely the conduit through which COVID-infected animals were forced into contact with humans (if pangolins are finally confirmed as the intermediary host, it would be an ironic twist, as they’re the most traded mammal worldwide, with all eight known species in the IUCN Red List of Threatened Species, three of which are classified as critically endangered). Traded wildlife is sold for food, for parts, as pets, for traditional medicinal uses, and others. In many parts of the world, wildlife consumption and use are deeply-rooted cultural practices. As demonstrated by China’s swift ban of all wildlife trade for consumption, forcefully limiting human exposure to wildlife is a fundamental step to prevent the emergence of new EIDs. Improving hygienic conditions along the entire legal wildlife trade chain, and imposing strict and safe conditions for its sale and consumption, are also key. These elements are usually weak in many countries, where the veterinary services for livestock are well advanced, but practices for inspection of wildlife are not fully developed and integrated

Getting too close to wildlife – habitat degradation

Biodiversity provides a key service many of us are less familiar with: disease regulation. Natural biodiversity limits the exposure and impact of many pathogens through a dilution or buffering effect, thus minimizing opportunities for pathogen spillover to humans. Deforestation and land use change, habitat fragmentation, encroachment, rapid population growth and urbanization are some of the ecological, behavioral and socioeconomic factors that amplify human exposure and multiply chances of contagion. Climate change is an additional, known driver of EIDs, creating new opportunities for pathogens, accelerating the appearance of invasive species and displacing the range where natural species occur.

Anthropogenic activities are eliminating the buffering effect that biodiversity and ecosystems provide, increasing the risk of the next pandemic.

All of these drivers allow researchers to determine hotspots of zoonotic EID risk, and findings show that risk is elevated in forested tropical regions experiencing land use changes and where wildlife biodiversity (mammal species richness) is high. China and Southeast Asia are known hotspots as well. Anthropogenic activities are eliminating the buffering effect that biodiversity and ecosystems provide, increasing the risk of the next pandemic. Reversing these trends is, more than ever, an issue of global relevance for public human health.

One Health

While plenty of EID-related attention and expenditures are devoted to the human part of the equation (preparedness and emergency response, public health), greater attention should be given to halting the main drivers that cause EIDs in the first place. One Health approaches recognize that human and animal health are interdependent and bound to the health of the ecosystems in which they exist. The World Bank’s recent announcement of US$12 billion for COVID-19 country responses gives us the chance to build a comprehensive package of action that includes human, animal and environmental health. The latter is usually the weakest link. As development practitioners, we should engage the ministries of environment and natural resources, wildlife departments, research institutions, NGOs and civil society, and address gaps on wildlife health surveillance and disease emergence, wildlife trade veterinary practices, hygienic regulations, wildlife trade policies and practices, and effective communication of risks.

Human and animal health are interdependent and bound to the health of the ecosystems in which they exist.

As the coronavirus continues to spread, the promotion of environmental health as a key element of our own health, and of activities that severely limit human exposure to wildlife are more urgent than ever. Preventing the next Pangolin Effect starts by curbing illegal wildlife trade and better regulating legal trade, improving biodiversity and habitat conservation and maintaining robust ecosystem services. The window of opportunity is both wide open, and short-lived.

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