How Geography Impacts Flu Outbreaks

HEALTH

The physical geography of cities—in particular, the differences between a city’s urban core and its suburban periphery—may help guide public health planning. (Pacific Standard)

Use our activity to learn how researchers can map an epidemic—or stop one from happening.

Teachers, scroll down for a quick list of key resources in our Teachers’ Toolkit.

The megacity of Dhaka, Bangladesh, was the test case for geographers studying how physical geography contributes to the spread of disease. Photograph by Jonas Bendiksen, National Geographic

The megacity of Dhaka, Bangladesh, was the test case for scientists studying how physical geography contributes to the spread of disease.
Photograph by Jonas Bendiksen, National Geographic

Discussion Ideas

  • New research focuses on the connection between physical geography and the spread of disease. What is physical geography?
    • Physical geography describes the natural features and processes of the Earth.
    • Physical geography may include study of the atmosphere (climate and the processes that contribute to it), geology (landforms and the processes that made them) and biosphere (ecosystems and how they function).

 

  • Researchers focused their study on outbreaks of rotavirus in and around Dhaka, Bangladesh. What is rotavirus?
    • Rotavirus is one of the leading causes of the stomach flu and diarrheal disease, accounting for the deaths of about 215,000 children every year.

 

rotavirus_deaths_map_a

Children in developing countries are particularly at-risk during rotavirus outbreaks. Map and chart by the World Health Organization

Children in developing countries are particularly at-risk during rotavirus outbreaks.
Map and chart by the World Health Organization

  • Why do you think Dhaka was chosen for this study of physical geography and outbreaks of rotavirus?
    • Children in developing countries are particularly at-risk for rotavirus, and researchers were interested in studying the relationship between physical geography and disease in urban centers. Dhaka fit these interests:
      • Bangladesh a developing country, and Dhaka is a megacity—usually defined as an urban area with a population of more than 10 million. Dhaka is the most densely populated city on the planet, with its 14.5 million residents squeezed into 44,000 people per square kilometer (115,000 people per square mile).
      • Bangladesh shares a border with India, the country that suffers the most child deaths attributable to rotavirus—and a country with three megacities (Delhi, Mumbai, and Kolkata).

 

This population density map shows the core and periphery of Dhaka, Bangladesh. Each gray dot refers to the density at a resolution of one square kilometer. Diamonds in red label the peripheral thanas of Narayanganj Sadar and Bandar. “Matlab” is the rural area south of Dhaka. Illustration by Pamela P. Martinez, Aaron A. King, Mohammad Yunus, A. S. G. Faruque, and Mercedes Pascual, “Differential and enhanced response to climate forcing in diarrheal disease due to rotavirus across a megacity of the developing world” PNAS 2016 113 (15) 4092-4097; published ahead of print March 28, 2016, doi:10.1073/pnas.1518977113

This population density map shows the core and periphery of Dhaka, Bangladesh. Each gray dot refers to the density at a resolution of one square kilometer. Diamonds in red label the peripheral thanas of Narayanganj Sadar and Bandar. “Matlab” is the rural area south of Dhaka.
Illustration by Pamela P. Martinez, Aaron A. King, Mohammad Yunus, A. S. G. Faruque, and Mercedes Pascual, “Differential and enhanced response to climate forcing in diarrheal disease due to rotavirus across a megacity of the developing world” PNAS 2016 113 (15) 4092-4097; published ahead of print March 28, 2016, doi:10.1073/pnas.1518977113

  • The study found stark differences in rotavirus outbreaks in Dhaka’s “core” and “periphery.” How did researchers define Dhaka’s core and periphery?
    • Researchers considered the thanas of Dhaka and its surrounding areas. (A thana is an administrative unit in Bangladesh, similar to a city district or ward.) Thanas in Dhaka’s core were urban, while thanas in Dacca’s periphery were suburban and rural.

 

  • What specific element of Dhaka’s physical geography was correlated to outbreaks of rotavirus?
    • Climate, which includes temperature and precipitation. Specifically, researchers found a dramatic difference between Dhaka’s core and periphery when considering the impact of seasonal monsoon-related flooding.

 

 

  • How do you think this research correlating physical geography and rotavirus outbreaks might influence public health planning?
    • Municipal health authorities may be able to anticipate outbreaks of rotavirus ahead of predictable climate events (such as the monsoon), and be more prepared with increased pharmaceuticals, equipment, and staffing in a city’s core.

 

TEACHERS’ TOOLKIT

Pacific Standard via The Week: How geography impacts flu outbreaks

Nat Geo: Mapping A London Epidemic activity

(extra credit!) Proceedings of the National Academy of Sciences of the United States of America: Differential and enhanced response to climate forcing in diarrheal disease due to rotavirus across a megacity of the developing world

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