Particles to Populations: Bioengineering Professor Caroline Wagner researches disease spread

Recently hired by McGill’s Department of Bioengineering, Professor Caroline Wagner studies the role of physical and biological processes in the spread and progression of diseases, in particular, how biological fluids like mucus interact with pathogens in the body, and affect their transmission between people at the level of populations.
Image by Marlon Kuhnreich.

Professor Caroline Wagner is part of a new cadre of researchers who take an interdisciplinary approach, and her work combines immunology, epidemiology, climate science, mathematical modeling, and engineering sciences, to tackle the global health challenges of the future.

You began your academic career as a mechanical engineering undergraduate student at McGill. How did you end up focusing on global health?

Caroline Wagner: By doing research with Professors John Lee and Andrew Higgins in Mechanical Engineering on combustion-related projects, I discovered I liked fluid mechanics. It turns out this field plays a big role in disease transmission. You need to understand fluid mechanics to model disease spread via emi¬tted droplets in the air, and also to model the effect of all these biofluids we have in our bodies, like mucus and blood, in various disease contexts. My Ph.D. at MIT was spent thinking about the mechanical properties of biofluids and developing models to understand how changes in these properties might be related to various states of disease. I took classes in public health and development economics, and got interested in the bigger global health picture. I ended up doing a postdoctoral fellowship at Princeton developing mathematical models for how diseases spread within-hosts and at the level of populations. It became clear to me that biofluids play a big role in these processes. Many infectious diseases spread via droplets we emit, which contain mucus and its main protein components. Mucus also acts as a barrier within hosts, and can trap viruses, denying them access to the cells they would otherwise infect. I realized I would build my research program to incorporate these aspects of biofluids and bioengineering into thinking about modeling disease progression and transmission. Then the pandemic broke out a year and a half later. It was bizarre timing.

Have you learned anything from COVID-19 that we could use the next time there’s a pandemic?

C.W.: I think having systems in place to rapidly mobilize data will be hugely important for the future, to help with public planning. Though ultimately there needs to be infrastructure connecting hospitals or public health agencies collecting these data with research teams. The pandemic has shown us that our responses need to be adaptable as we learn more about the disease in question—another strong reason to efficiently handle data. We can think about how to improve our baseline level of preparedness or ability to identify future threats. I didn’t come up with this idea, but among my colleagues there is interest in se¬tting up a system or observatory to monitor immunity levels to different diseases, say from random blood samples. Combining this with the monitoring of active infections could be very useful.

How is climate change going to affect public health?

C.W.: In lots of ways. During my postdoctoral fellowship I got to work with a team from Princeton that combines researchers from Ecology and Evolutionary Biology and the High Meadows Environmental Institute. We ended up combining both epidemiological and climatological data sets to think about the role of climate in a large Dengue virus outbreak in Sri Lanka in 2017. But it’s not just mosquito-borne diseases that are impacted by climate. Aerosol-transmissible diseases, too: people get the flu more in the winter, for example. We don’t necessarily know if that’s because people are staying inside and staying close to each other, or if the weather is affecting either our immune system or the virus particles directly. That’s an example of a big open question that engineers could play an important role in helping answer. If these seasonal disease pa¬ erns become different with climate change, that can have huge impacts on public health planning.

What is the role of universities and their researchers in helping to manage infectious disease?

C.W.: It’s true that not all university researchers are directly involved in policy decisions. But many people at McGill work very closely with provincial and federal health agencies, in the generation of projections for case numbers and infections. When researchers publish their work, this is picked up and used by policy makers, and many of our public health researchers have devoted a lot of time, particularly during the COVID-19 pandemic, to communicating their knowledge to broader, non-academic audiences through various media and social media platforms.

Will your lab at McGill be an interdisciplinary one, then?

C.W.: Yes! The students who are keen on the biofluids side of the work will be from bioengineering, mechanical engineering, chemical engineering and so on. I’ll also be recruiting people with a quantitative background who are interested in epidemiology. I think there’s a lot to learn from connecting those two areas.

This article was originally published in the Faculty of Engineering Dean's Report Fall 2021

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