How the world can prevent emerging infectious diseases and protect food security
According to a new report co-written by Illinois Natural History Survey postdoctoral researcher Valeria Trivellone, climate change, poverty, urbanization, land-use change and the exploitation of wildlife all contribute to the emergence of new infectious diseases, which, in turn, threaten global food security. Trivellone spoke with News Bureau life sciences editor Diana Yates about how global authorities can tackle these intertwined challenges.
How do emerging infectious diseases affect food security?
Emerging infectious diseases threaten food security by disrupting food systems and increasing food prices, both locally and globally. New infectious diseases may start out as infections in wild animals in natural areas, but as we modify these landscapes, they emerge more often than expected. The pace of this crisis seems faster than our ability to understand and adapt.
Our research revealed that most emerging and reemerging infectious diseases have minimal economic impacts by themselves, but their combined impact in treatment costs and production losses comes to at least $1 trillion per year. And because we live in a fast, hyperconnected world, everyone is affected to some degree and these effects are cumulative. Global climate change is speeding the emergence of new infectious diseases and is expected to have lasting socioeconomic effects, even in food-secure regions.
How do urbanization, globalization and climate change contribute to the emergence of new infectious diseases?
Global warming allows pathogens to expand their geographic distribution and come into contact with previously unexposed hosts. Cities are incubators for emerging infectious diseases, many of which are brought in by globalized trade and travel. The convergence of these factors sets the stage for the emerging infectious disease crisis to become an existential threat to humanity.
More than 50 years ago, seminal contributions by the epidemiologist J. Ralph Audy and the zoologist Charles Elton anticipated this crisis. In the past decade, my co-authors on this work have helped disentangle the evolutionary and ecological factors that explain why new infectious diseases are emerging so rapidly at this time.
What is wrong with the way we currently think about emerging infectious diseases?
People in public health and the livestock and agricultural sectors tend to cope with emerging infectious diseases in "crisis response" mode, waiting for an outbreak to occur before surging into action. If, as is increasingly the case, that activity is not successful, the increased costs are passed along to consumers in the form of higher food prices—often in countries that can least afford it. Each emerging disease becomes normalized as "the cost of doing business."
The false belief that a pathogen must evolve specific new genetic capacities to successfully infect a new host leads people to think that we cannot do more to stop this process before it becomes problematic. But we now know that pathogens do not require novel mutations to infect new hosts. All that is required is the opportunity to be exposed to susceptible hosts that have never been exposed before. After a pathogen has become established in a new host, then new genetic variants may evolve.
Global climate change allows species to move away from their places of origin, giving pathogens opportunities to emerge rapidly in new hosts. Travel and globalized trade—including trade in wildlife species—add to the movements of hosts and pathogens around the planet. Along with the expansion of anthropogenic habitats, land-use modification and fragmentation of natural landscapes further increase the opportunities for pathogens to emerge in crop fields.
How can we lessen the likelihood of future outbreaks?
Because emerging infectious diseases make use of preexisting genetic capabilities to take advantage of new opportunities, we can predict where they are likely to occur and how they are likely to behave. This means we have a chance to "anticipate to mitigate" their impact. And we all know that prevention is more effective and less costly than crisis response.
For example, a bacterial plant disease called aster yellows causes losses annually to a wide range of farm and horticultural crops in the U.S. When an outbreak occurs, people tend to think of it as an event that could not be foreseen. But we have information that could allow us to anticipate and mitigate this plant pathogen. For example, very recently in Illinois, a horticulture educator reported cases of aster yellows on black-eyed Susans and coneflowers, flowering plants often found in gardens. These non-crop plants can serve as reservoirs of the pathogen.
When we move such plants from natural areas to our anthropogenic spaces, we create new opportunities for the pathogens to invade new hosts, and then innovate and potentially jump to yet more plants—including crop species—causing economic costs. I am not saying we should not populate our backyards with native plants. The biology of such associations follows certain rules, and that it is possible to find and eradicate newly introduced pathogens before they spread.
How can we strengthen food security around the world while addressing these challenges?
Coping with emerging infectious diseases is fairly simple in principle, but it means that we must switch from crisis response to effective prevention. We need highly sophisticated molecular laboratories and technologies. We also need to teach stakeholders how to avoid the spread of pathogens on their own farms, gardens and water supplies.
The information we assemble must be integrated into well-maintained natural history collections and archives. These are the sources of historical data that help us avoid repeating past mistakes. And government officials and public policy specialists must understand that crisis response is always more expensive than prevention.
What kinds of initiatives will make this possible?
While we wait for national and international support for programs—such as the DAMA protocol, the one proposed in our work—to aid the prevention and mitigation of emerging infectious diseases, we can take action at the grassroots level. Illinois naturalists are the custodians of an immense legacy of knowledge about the natural history of pathogens and how they are transmitted in the environment. We need to connect their knowledge with the technological capabilities of the generations that will feel the greatest weight of this crisis. Efforts at the U. of I. like the citizen-scientist tick collection program are examples of this approach.
Won't this be expensive?
There are no benefits without costs. But coping with emerging infectious diseases in crisis response mode is more expensive than anticipating and mitigating their impacts. An ounce of prevention is always worth a pound of cure.
We were given a preview of the potential costs of inaction with the global economic meltdown accompanying the SARS-CoV-2 pandemic. If we care about our children and grandchildren, we must change our policies now.