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.

TEDMED Research Scholar

This year I’ll be serving as a Research Scholar for TEDMED 2020!

Source: – TEDMED Blog

The TEDMED Research Scholars are a carefully selected group of passionate and objective individuals whose expertise spans the biomedical, public health, and emerging technology spectrums. Every year, Research Scholars help us to vet the science and timeliness of our TEDMED Speaker nominations, allowing us to better examine the diverse nominations we receive.

2019 Ecology & Evolution of Infectious Disease (EEID) Conference

This year the EEID conference was held at Princeton University from June 10-13, 2019. The four guiding themes were:

  • Behavioral drivers of disease dynamics
  • Genetics of disease dynamics across scales
  • Environmental drivers of disease
  • Consequences of within-host competition for disease control across scales

This year I tried something different for note taking: I brought my digital pad and creating conference doodles. Conference doodles are a science communication tool that link the  material of the talk with illustrations. I found this was a fun way to keep my attention focused and to practice condensing the material into salient takeaway points. It was also really fun to draw mosquitoes, spirochetes, aphids, and other sundry pathogens and vectors.

Tuesday, June 11, 2019 

Lindy McBride: “Geographic, genetic, and neural origins of human biting in the mosquito vector Aedes aegypti”

L. McBride.jpg

Continue reading “2019 Ecology & Evolution of Infectious Disease (EEID) Conference”

Research spotlight: Modeling how diseases spread

In order to predict and fight animal disease outbreaks, epidemiologists and other researchers need to understand how a given disease spreads through landscapes and populations. Factors contributing to the ability of a pathogen to spread include the features of the environment as well as the movement of the animals through that landscape. Human activity is changing landscapes, with the result that they are becoming increasingly heterogeneous (with differences occurring across the landscape). The effect of this increasing heterogeneity on the spread of disease is unclear…

Excerpt from: Minnesota Supercomputing Institute (March 15, 2019). “Research spotlight: Modeling how diseases spread”

Read more: https://www.msi.umn.edu/research/modeling-how-diseases-spread