Ask a professor: Tick Project’s Felicia Keesing says that less biodiversity means more diseases

Bard College Biology Professor Felicia Keesing

Tick Project’s Felicia Keesing: Less biodiversity means more diseases

Bard College recently announced that Felicia Keesing, the college’s David and Rosalie Rose Distinguished Professor of Science, Mathematics and Computing, has been awarded a $241,000 grant from the National Science Foundation (NSF). Professor Keesing has spent nearly 30 years researching the complex relationships among ecology, conservation and health. The NSF grant will fund two papers that will synthesize a quarter-century of Keesing’s research and aim to provide better conceptual frameworks for the study of the impacts of biodiversity on plant, animal and human health.

“Ecology is increasingly seen as a key ally of the health sciences,” Keesing says, “but concrete examples of how ecology can productively inform health policy remain relatively scarce. The proposed syntheses could impact environmental policies that affect the health of humans, other animals and plants, in part by framing research questions that urgently require exploration and explication.”

Keesing is well-known to Hudson Valley locals as an influential researcher of Lyme disease who has studied tickborne illnesses for 25 years. She co-founded (with Richard Ostfeld) the Cary Institute of Ecosystem Studies’ Tick Project, a five-year study to determine whether neighborhood-based prevention can reduce human cases of Lyme and other tickborne diseases. Since 1995, Keesing has studied how African savannas function when large, charismatic animals like elephants, buffaloes, zebras and giraffes disappear.


Professor Keesing agreed to answer a few questions about the NSF grant and to illuminate the relationship between ecology and disease, here at a time when such issues are front-and-center in most people’s minds:

In the press release announcing the grant award, you are quoted as saying, “While the field of disease ecology has held great promise because of the expectation that its practitioners can facilitate predictions and guide ecological interventions to mitigate health concerns connected to the environment, too frequently, predictions come too late to be useful.” Can you provide an example or two of instances in which this latency really derailed or delayed science’s effective response to a public health crisis? How common is that? What are the bottlenecks?

Imagine a situation in which a new infectious disease is identified. (Just imagine!) It’s spreading and beginning to affect humans. In the case of coronavirus, which we’re all experiencing very intensely right now, scientists had been warning that certain species were more likely to harbor viruses that could jump to humans, and some of those species were being housed in optimal conditions for such jumps to occur. In that case, I’d say that the scientists did their job pretty well, even though we still don’t know what species carried the specific virus that’s causing Covid-19, and even though there are lots and lots of other challenges involved with managing this outbreak.

But in other cases – say, the case of a new tickborne infection – we need to be able to more quickly identify the likely sources of the pathogen, and also the wildlife species that protect us from infection. It would also be very useful if we knew the kinds of situations that make it more likely that an infection will emerge. If we knew that, for example, losing biodiversity would increase the risk of an infection, we could encourage policies that protect biodiversity. These are the kinds of interactions between infections and the environment that I’m most interested in exploring with this grant.

Can you provide some examples of the critical ways in which you foresee modifying, streamlining or tech-enabling this science-into-practical-response process for greater readiness and timeliness?

Much of what I’m proposing to do would be a synthesis of ideas that have already been proposed and, in many cases, demonstrated. For example, my colleague Rick Ostfeld of the Cary Institute of Ecosystem Studies and I have uncovered evidence of a “dilution effect,” in which habitats with a high diversity of animals include species that dilute the risk of a tickborne infection like Lyme. In habitats with low diversity of animals, like a tiny forest fragment, the species that thrive are the species most likely to pass infections on to us. One of the papers I’ll be writing with this grant support will explain the dilution effect to non-specialists. Another will attempt to unify a lot of disparate ideas about how biodiversity can affect our health. A lot of these ideas have not yet been well-described or integrated.

It sounds like a key element of this current work is really about information systems and management – a big, hyperspecialized IT job, in some respects. Is that accurate?

There are a lot of people working on how to use IT to predict and manage infections. That’s not my particular focus. I’m interested in understanding what’s happening in nature, and what kinds of patterns occur across different disease systems, so that we can use this information to make better decisions in the future.

The project I’m working on with this grant builds on my 25 years of working on tickborne illnesses in the Hudson Valley and even longer working in the savannas of East Africa. What my colleagues and I have learned by studying these systems can be used to predict what’s likely to happen in other places. For example, what kinds of infectious diseases are likely to be affected by changes in biodiversity? From my Kenya work, I’m interested in how changes to biodiversity affect human health in a variety of ways, including their economic and social well-being, and also the sustainability of savanna environments.

Looking over your diverse, award-filled bio, one thing I notice is that your career seems defined by its direct intersections with culture and daily life. Lyme defines life and psychology in the Northeast; African mammals profoundly symbolize both the magic and the fragility of the natural world; and right now you are tapping right into an area of acute neurosis, if not mania! If you agree with that assessment at all, was this conscious? Were you committed or drawn to the “relevant” or the especially human/humane dimensions of science and research from the start of your career, or am I missing the point that all areas of science will find these intersections if you follow the threads far enough?

This is an interesting insight. I have a deep respect for basic science and have done a fair bit of it myself. That said, I am particularly drawn to questions that have relevance in the world. My Kenya work has focused on whether it’s possible for humans and wildlife to coexist in African savannas in the 21st century. I have been working in Kenya since the 1990s, addressing this question in a variety of ways. Most recently, we have found that wildlife on the one hand, and people and their livestock on the other, can coexist and even benefit from each other. I think these kinds of win/win situations are very compelling. They’re not always possible, of course, and we need to be wary of oversimplifying outcomes and tradeoffs, but there is much to be learned from identifying and working with win/win scenarios.

In the Hudson Valley, my colleagues and I have identified processes that benefit the environment and human health: another win/win situation. Our particular focus has been on tickborne diseases like Lyme and anaplasmosis, but our results apply to other diseases all around the world, and diseases of plants and wildlife as well as of humans.

Early in my career, I chose questions that had relevance to the world, and I continue to work on those questions today. My focus has changed, though, both in the Hudson Valley and in Kenya, so that now I’m working much more closely with local communities. Our Tick Project, which is in its fifth year in Dutchess County, is a good example. In that project, we’re working with about 3,000 residents of the county to see if environmental interventions in neighborhoods can reduce the number of cases of Lyme and other tickborne diseases. This is an obvious outcome of my decades of research on what causes some areas to be riskier than others for tickborne diseases; my focus now is how to use the knowledge we have to actually make a difference in people’s lives.