Landtalk and COVID-19

July 10, 2020

At the time I write this post, the world is in the midst of a global pandemic. In just seven months, a novel coronavirus, COVID-19, has infected nearly 13 million people and killed nearly 570,000. This new disease has closed schools, businesses, and borders as well. At least a third of the world’s population have been or still are staying at home to stop the spread of the disease, which we have no vaccine and no reliable treatment for. While a necessity, millions of people have lost their jobs as a result of these lockdowns. University students like me wait anxiously, wondering what the future of our education will look like and what kind of society and economy we will be graduating into. It is safe to say that the world will not be the same when we reemerge from COVID-19. 

How did this global catastrophe, which has killed hundreds of thousands and profoundly impacted the daily lives of billions, begin in the first place? Although the global pandemic must be understood through many different lenses, the origin and rapid spread of COVID-19 is intimately connected with the purview of Landtalk: land use change. This is because the majority of infectious diseases like COVID-19 emerge when a pathogen makes the leap from an animal host—usually wildlife—to humans, and then adapts to spread from person to person. While it may not be immediately obvious, landscape change puts people and animals into greater contact, increasing the odds that an infectious disease will emerge. Urbanization, a common form of landscape change on this site, is also connected with COVID-19’s rapid spread across the globe. More people than any other time in history live in densely populated cities, which creates the conditions for diseases to proliferate.

In this post, I want to explore these important connections between land use change and COVID-19, which speaks to the necessity of Landtalk and its goal of monitoring and documenting this change.

Habitat destruction and emerging diseases

COVID-19, like other coronaviruses, originated in bats. The first detected cases of the respiratory illness were initially linked to a seafood and live animal market in Wuhan, China. Scientists hypothesized that the disease first spread from a bat to a pangolin, which may have infected humans through the market. Further evidence, however, casted doubt on this claim. No animal samples from the market tested positive for the virus, and the first identified patients had not visited the market, suggesting the virus may have made the leap into humans through a different source. 

Although the specific pathway for this coronavirus outbreak has not yet been identified, researchers identified how the closely related SARS outbreak from 2002 to 2003 took hold. That outbreak emerged when horseshoe bats, the natural reservoir for the virus responsible for SARS and COVID-19, infected palm civets, a small mammal like the pangolin. These civets then transmitted the virus to humans in live markets and restaurants. 

How does this connect to landscape change and habitat destruction? Bats belong to a group of animals that can adapt to live in urban environments, like rodents and raccoons. When bat habitats are destroyed to make way for urban settlements, bats, people, and other species of wildlife begin to inhabit the same spaces, allowing viruses to cross over into other animals and then into us. Habitat destruction and the commercialization of animal wildlife for food and medicine have paved the way for two major outbreaks in the last decade, and if these conditions persist, there may be more to come.

Other diseases, not just coronaviruses, are also linked to habitat destruction. A recent Stanford study led by Laura Bloomfield found that in Uganda, clearing of natural habitats for agricultural purposes put people into closer contact with wild primates. The researchers found that although primates are well known carriers of disease and are usually avoided by people, “continued loss of forested habitat means wild primates and humans are increasingly sharing the same spaces and vying for the same food. When people venture into forested areas for resources and when animals venture out of their habitats to raid crops, the chances increase for transmission of zoonotic – or animal-to-human – disease.”

This was the case for HIV, Human Immunodeficiency Virus, which likely originated from Simian Immunodeficiency Virus, which infects chimpanzees and dozens of other non-human primates. Since its emergence around the beginning of the 20th century, HIV and Acquired Immunodeficiency Syndrome (AIDS), a disease which develops from an untreated HIV infection, has infected nearly 74.9 million and killed 32 million. In 2018, an estimated 770,000 people died of the virus. As HIV makes clear, the potential consequences of habitat loss are hard to wrap one’s head around.

Unfortunately, if current trends continue, this problem will only become worse. In 2011, researchers at the Royal Society wrote that “Infectious diseases from wildlife have emerged at an increased pace within the last century and are likely to continue to emerge, given expected increases in population growth and landscape change.”

Here on Landtalk, you can explore people’s first hand accounts of this type of landscape change. Here are some posts to get started:

Urbanization and the spread of disease

Destruction of natural habitats to create farmland or human settlements creates more avenues for dangerous diseases to make the leap into humans. Landscape change also interacts with infectious diseases after they have taken hold in human populations through urbanization. Urbanization, a phenomenon captured extensively on Landtalk, greatly changes the way diseases spread. Early on in the pandemic, the majority of COVID-19 cases have been in urban, densely populated areas. People live in close proximity not only to wildlife but also to other humans in urban environments, allowing respiratory diseases like COVID-19 to spread quickly.

This phenomenon is not new. From 1347 to 1351, the bubonic plague swept through Europe and killed between 30 and 50 percent of its population. The bacteria that caused this destructive disease was initially transmitted to humans from flea ridden rodents, which thrived in the dense cities of medieval Europe. Once the disease had taken hold, it easily spread through these crowded settlements, resulting in an incalculable loss of life.

Although urbanization and its impacts on the spread of disease are nothing new, the past 150 years have seen a dramatic increase in the number of urban dwellers. In 2020, more than half the world’s population—over 4 billion people—live in cities. That proportion is expected to increase to two thirds by 2050. Most of this increase will come from developing countries, where deforestation and habitat destruction are also highest. It is easy to envision a future where global pandemics become increasingly common under these conditions.

Even in countries like the United States, COVID-19 has caused many to question the future of urbanization. The virus, which is fought through social isolation, preys on the core tenet of urban life—community and interconnectivity. Michael Kimmelmann wrote in the New York Times that pandemics are ultimately “anti-urban.” He compares wealthy New Yorkers fleeing for second homes in the countryside to the characters in Italian writer Boccaccio’s novel The Decameron, who fled Florence in 1348 to escape the black death. To many who have the means, leaving the city is the easiest way to avoid disease. But what happens to cities if disease becomes the new normal?

Our desire to congregate in cities filled with community and culture did not end in Bocaccio’s time, however, and it is too soon to say what kind of impact COVID-19 will have on urbanization. Still, emerging infectious diseases may be among the most deadly challenges we will face in our ever urbanizing world.

Urbanization is an extensively examined topic here on Landtalk. You can explore the impacts of urbanization, particularly in developing countries, through these posts: 

‘Development’ and ‘urbanization’ are two of the most popular topics on Landtalk. If we retain one important lesson from COVID-19 and its devastation, it is that land use change cannot be ignored. The phenomena that thousands of citizen scientists have observed on this platform have far reaching consequences that may not be obvious at first glance. While each post on Landtalk represents an individual experience, the broad shifts that our planet is undergoing implicate all of us as world citizens.