New Call to Examine Old Narratives

Original post: https://www.sesync.org/news/fri-2020-05-01-1507/new-call-to-examine-old-narratives-infectious-disease-modeling-study-casts

Infectious disease modeling study casts doubt on the Justinianic Plague’s impact

Annapolis, MD — Many have claimed the Justinianic Plague (c. 541–750 CE) killed half of the population of Roman Empire. Now, historical research and mathematical modeling challenge the death rate and severity of this first plague pandemic.

Researchers Lauren White, PhD and Lee Mordechai, PhD, of the University of Maryland’s National Socio-Environmental Synthesis Center, examined the impacts of the Justinianic Plague with mathematical modeling. Using modern plague research as their basis, the two developed novel mathematical models to re-examine primary sources from the time of the Justinianic Plague outbreak. From the modeling, they found that it was unlikely that any transmission route of the plague would have had both the mortality rate and duration described in the primary sources. Their findings appear in a paper titled “Modeling the Justinianic Plague: Comparing hypothesized transmission routes” in PLOS ONE.

“This is the first time, to our knowledge, that a robust mathematical modeling approach has been used to investigate the Justinianic Plague,” said lead author Lauren White, PhD, a quantitative disease ecologist and postdoctoral fellow at SESYNC. “Given that there is very little quantitative information in the primary sources for the Justinianic Plague, this was an exciting opportunity to think creatively about how we could combine present-day knowledge of plague’s etiology with descriptions from the historical texts.”

White and Mordechai focused their efforts on the city of Constantinople, capital of the Roman Empire, which had a comparatively well-described outbreak in 542 CE. Some primary sources claim plague killed up to 300,000 people in the city, which had a population of some 500,000 people at the time. Other sources suggest the plague killed half the empire’s population. Until recently, many scholars accepted this image of mass death. By comparing bubonic, pneumonic, and combined transmission routes, the authors showed that no single transmission route precisely mimicked the outbreak dynamics described in these primary sources. 

Existing literature often assumes that the Justinianic Plague affected all areas of the Mediterranean in the same way. The new findings from this paper suggest that given the variation in ecological and social patterns across the region (e.g., climate, population density), it is unlikely that a plague outbreak would have impacted all corners of the diverse empire equally. 

xenopsylla cheopis
Photo: Xenopsylla cheopis

 “Our results strongly suggest that the effects of the Justinianic Plague varied considerably between different urban areas in late antiquity,” said co-author Lee Mordechai, an environmental historian and a postdoctoral fellow at SESYNC when he wrote the paper. He is now a senior lecturer at the Hebrew University of Jerusalem, and co-lead of Princeton’s Climate Change and History Research Initiative (CCHRI). He said, “This paper is part of a series of publications in recent years that cast doubt on the traditional interpretation of plague using new methodologies. It’s an exciting time to do this kind of interdisciplinary research!”

Using an approach called global sensitivity analysis, White and Mordechai were able to explore the importance of any given model parameter in dictating simulated disease outcomes. They found that several understudied parameters are also very important in determining model results. White explained, “One example was the transmission rate from fleas to humans. Although the analysis described this as an important parameter, there hasn’t been enough research to validate a plausible range for that parameter.” 

These high importance variables with minimal information also point to future directions for empirical data collection. “Working with mathematical models of disease was an insightful process for me as a historian,” reflected Mordechai. “It allowed us to examine traditional historical arguments with a powerful new lens.” 

Together, with other recent work from Mordechai, this study is another call to examine the primary sources and narratives surrounding the Justinianic Plague more critically. 

White, L.A. & Mordechai, L. (2020). Modeling the Justinianic Plague: Comparing hypothesized transmission routes. PLOS ONE. doi: 10.1371/journal.pone.0231256

Contact information:

Lauren White, lwhite@sesync.org, National Socio-Environmental Synthesis Center, University of Maryland

Lee Mordechai, lmordechai@sesync.org, Hebrew University of Jerusalem.

About SESYNC

The University of Maryland’s National Socio-Environmental Synthesis Center (SESYNC) in Annapolis brings together the science of the natural world with the science of human behavior and decision making to find solutions to complex environmental problems. SESYNC is funded by an award to the University of Maryland from the National Science Foundation. For more information on SESYNC and its activities, please visit www.sesync.org.

SESYNC’s Public Health Immersion Workshop: Interdisciplinary Themes of Resilience and Social Determinants of Health

By: Lauren White

Original post: https://www.sesync.org/news/tue-2020-02-25-1935/sesync%E2%80%99s-public-health-immersion-workshop-interdisciplinary-themes-of

In a recent Immersion workshop on public health, SESYNC postdocs had the opportunity to interact with three public health scholars whose research programs span environmental exposure, feedbacks between human health and sustainability, and mental health and cognition. During the two-day workshop, these scholars covered a range of topics—beginning with the foundations of public health and public health methods and then building to the applied contexts of how to foster community engagement, develop community partnerships, and manage these relationships in an international setting.

Jennifer Vanos, Assistant Professor in the School of Sustainability at Arizona State University, researches the effect of extreme heat and air quality overexposure on human health, especially in vulnerable populations. Her work focuses on a solution-based approach to understanding how we can modify the environment to mitigate these risks. Katie Fiorella, Assistant Professor in the Master of Public Health Program and the Department of Population Medicine and Diagnostic Sciences at Cornell University, explores the links between environmental change and human health and food security in her research. A common research question is how the environment affects human health, but Dr. Fiorella also investigates an under-explored corollary: how human health affects how humans manage the environment. Within the field of environmental psychology, Gregory Bratman, Assistant Professor in the College of Environment at the University of Washington, investigates how our experience of nature affects human cognition and functioning.

One of the interdisciplinary goals of SESYNC involves creating a culture where researchers have appropriate knowledge of other disciplines and have opportunities to engage in dialogue and develop a common language. During group discussions and reflections, SESYNC postdocs were challenged to identify how their research connects with public health research themes. For Xavier Benito-Granell, PhD, a SESYNC postdoctoral fellow focusing on paleoecological questions, resiliency was a connecting theme for the workshop. “[Resiliency] embraces a wide spectrum of disciplines, including public health and ecology, in the sense that communities (individuals, societies, ecological [systems]) have the capacity to adapt and respond to long-term stresses and disturbances,” Dr. Benito-Granell reflected. Likewise, postdoctoral fellow Florian Gollnow, PhD, found that the ecosystem benefits of nature for health and human well-being tied into the conceptual understanding of his research on tropical deforestation. 

Social determinants of health were another emergent theme of the Immersion workshop. Many participants learned for the first time that public health researchers quantify human health and well-being  as a function of genetics, medical care, and social determinants (e.g., education opportunities, income level, racial segregation). SESYNC postdoctoral fellow, Fushcia Hoover, PhD, a social-ecological urban hydrologist who infuses her research with approaches from environmental justice theory found the workshop to be a valuable experience. “I was motivated and encouraged by the scholars’ and workshop’s emphasis on building healthy and happy communities. It was great to see a field [public health] that does not put all the responsibility on the individual but recognizes the institutional drivers that affect health and well-being,” said Dr. Hoover. 

This workshop was part of SESYNC’s Immersion Program, which offers a series of collaborative workshops led by distinguished scholars. This program is designed to immerse participants in theories and methods foundational to understanding current environmental challenges and their underlying socio-environmental systems.