Apr 28 2020

Shah Selbe

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Photo credit: Shah Selbe

One of the things we know about infectious disease outbreaks, and which applies to the new COVID-19 pandemic, is that they are linked closely to issues around biodiversity. Viruses like Ebola, SARS, MERS, HIV, and other pathogens originally came from interactions between wildlife and humans. The United States Centers for Disease Control and Prevention estimates that these interactions account for as much as 75 percent of emerging diseases today. These diseases are zoonotic, meaning they crossed over from nonhuman animals to people. A 2008 paper in Nature estimated that 60% of the diseases that impacted humans between 1960 and 2004 followed that same pathway. In places that have high biodiversity, and even greater species diversity (including associated viruses, bacteria, and parasites), the potential for these types of interactions is increased. There are several urgent issues that the scientific, technology, and public policy communities must address to reduce animal to human disease transmission and prevent the next pandemic.


Deforestation around the world is devastating for global health as rainforests hold a significant amount of the remaining biodiversity on this planet. While they only cover about two percent of the Earth’s land surface area, they are home to over 50 percent of the terrestrial plants and animals. The Amazon rainforest alone is home to ten percent of the world’s known species. This biodiversity is an incredible asset to our planet, providing a deeper and more rich fabric of life across the globe. These rainforests possess a number of incredibly important insights about life on this planet and how to protect it. 


Deforestation in areas of vast biodiversity is leading to abnormal interactions among different species. There are a number of drivers that have enabled cross-species disease transmission, but many of those can be tied back to the issue of habitat loss. As people move into areas that traditionally had little to no human traffic, new contact with animal species increases the opportunity for transmission events. “We cut the trees; we kill the animals or cage them and send them to markets,” says David Quammen, author of Spillover: Animal Infections and the Next Pandemic. “We disrupt ecosystems, and we shake viruses loose from their natural hosts. When that happens, they need a new host. Often, we are it.” Rainforest ecosystems have evolved an intricate balance between the viruses, bacteria, plants, and animals that make up an area. Over long spans of ecological time, these relationships form a delicate balance that keeps things in check. As humans destroy this habitat or consume the animals that make up that ecological balance, we create the possibility of a spread of a bacteria or virus in those areas. When that is something that has never infected humans, the outcome can become catastrophic. 

Scientists spend considerable effort in studying the diseases in animals known to harbor potential zoonotic mechanisms. A more robust framework around the understanding of this connection has become so important that it has spurred a new academic discipline: planetary health. The hope is that by focusing on the interactions between human health and ecosystem well-being, we can better understand the potential for these sorts of outcomes in the future. As human populations expand into these areas, we see more stress on existing ecosystems and informal markets form that specialize in hunting for exotic meats. Often called the “bushmeat trade,” these hunters (and poachers) often sell wild-caught animals for consumption in open-air markets. These “wet markets” have become the epicenter of infectious disease potential. It was one of these markets in Wuhan that the current COVID-19 pandemic was traced back to, where scientists now believe that this transmission came from the consumption of the rainforest-dwelling Malayan pangolin. A paper recently came out in Nature documenting the existence of SAR-CoV-2 related viruses in those same animals found in that market. Additionally, we need to be careful about how these diseases can be then passed on to other nonhuman animals. Ebola was estimated to wipe out a third of the remaining western lowland gorilla populations during the same time that it was impacting humans.   


There are also valuable insights we are losing from deforestation. Indigenous communities have a rich connection to their lands and have taught us incredible lessons about how to survive and make sustainable use of the resources the ecosystems provide. The field of ethnobotany has looked at practical uses of plants, through the prism of this traditional knowledge. This work has resulted in incredible live-saving medicines that could only be found in rainforests, including seventy percent of the plants identified by the United States National Cancer Institute as useful in the treatment of cancer. Unfortunately, the history of this practice has been exploitative, where the profits that come from these pharmaceuticals never make their way back to help the communities that supported that work. Often considered biopiracy, this practice must not continue as we work to promote a more sustainable future for rainforests and their inhabitants. A movement is happening broadly in ecology to focus on community-based efforts in support of research objectives. The same should be applied to the sustainable screening of rainforest species for medicinal purposes. It is estimated that fewer than ten percent of rainforest plant species and 0.1 percent of animal species have been examined for their medicinal value, so there is considerable opportunity to do this the right way. 


We find ourselves at a very critical point in our global consciousness about the role that biodiversity and ecosystems play in our lives. We have never had a better understanding of our impact on this planet and the consequences of deforestation and environmental destruction. As we watch the way that this COVID-19 pandemic has changed so much around the globe, we must think about how we can avoid a similar catastrophe in the future. A tragedy like this, while avoidable, is here. But we find ourselves in the place to build a better world on the other side of this. China has banned the wildlife trade, with the pledge to completely revise the laws around wildlife exploitation. Air and water quality have improved with fewer people on the roads and our rivers. We all understand how things people use or eat in one part of the globe can change the lives of those in other places. The world has banded together to create innovative solutions to protect the vulnerable and health care workers. These positive shifts can and should inspire us to be more resilient, more collaborative, and more sustainable in a post-COVID-19 world.  

It is important that Rainforests remain protected and better understood. Fortunately, there is a growing understanding globally about the importance of protecting these places as intact ecosystems and to move beyond the exploitative extraction that has been commonplace in tropical areas for centuries. XPRIZE recently launched the Rainforest XPRIZE, which aims to find better ways to understand biodiversity in rainforests. The updated guidelines are available here and teams are able to join the competition until March 15, 2021. The innovation from this competition has the opportunity to drastically change the way we value and understand these critical ecosystems. This has never been more important than now. 

Shah Selbe