The United Nations recently released the report Preventing the next pandemic - Zoonotic diseases and how to break the chain of transmission that identifies seven human-influenced factors driving the emergence of zoonotic disease. Land use changes and unsustainable agricultural practices are among the leading factors identified. Other findings also substantiate that the health of both human and ecosystems is harmed by practices that lead to mass deforestation – which is driven primarily for the expansion of large-scale commercial agriculture. In response to this challenge, Stanford researchers have been examining ways to encourage sustainable land usage through diversified agricultural practices that allow for more retention of natural buffer zones that improve biodiversity. They’ve also been able to demonstrate linkage between forest loss and human activity with disease transmission.
Despite efforts to limit deforestation, which included global intergovernmental initiatives to restore degraded landscapes such as the Bonn Challenge, some regions and countries have instead accelerated the pace of forest loss. This ongoing destruction and mismanagement of forests along with increased encroachment into natural habitats leads to more potential human-wild animal interactions that may give rise to diseases with pandemic potential. In fact, many of the world’s most daunting infectious diseases including Ebola, SARS, AIDS and Lyme did make their way from animals to humans. These zoonotic transmissions likely occurred because humans came into close contact with animals, most typically as people ventured into their natural habitats to engage in activities such as agriculture, hunting or gathering of food and firewood, timber harvesting and, in the case of Lyme disease, outdoor recreation.
The evidence for the initial transmission pathway of COVID-19 is also pointing towards animals, specifically bats, who harbor many viruses to which they themselves have immunity. Scientists at Stanford and around the world continue to study how these types of infectious diseases jump from animals to humans because of the ways humans now interact with the natural world. People and their activities now dominate the planet, with more than a third of the world’s arable land surface now being used for agricultural activities. And these usage trends are particularly prevalent in the most vulnerable regions of the globe where zoonotic diseases primarily arise. Ultimately, preventing further deforestation while balancing the human need for food and economic security will be better for our own health.