Relationship Between Cholera and Ocean Net Heat Flux in the Bay of Bengal

1
Relationship Between Cholera and Ocean Net Heat
Flux in the Bay of Bengal

• By Erin James
• Department of Geography
• University of California, Santa Barbara

2
Introduction

• Research questions
• Cholera a brief history
• Remote sensing and cholera prior research
• Study area
• Data
• Methodology
• Conclusion

3
Research Questions

• Does climate change affect disease?
• Can the environmental factors associated with
  disease be quantified from space?
• What is the association between plankton blooms
  and cholera outbreaks?
• Can we create an accurate model to predict when
  cholera outbreaks will occur?

4
Cholera A Brief History

• 10 A.D. Historical records in Greek and
  Sanskrit describe cholera-like disease
• 1563 First epidemic of cholera described by
  Garcia del Huerto in India
• 1817 First recorded pandemic. Lasted six years
  related to wars occurring at the time
• 1829-1851 Second pandemic spread from Russia to
  Americas. Hit New York in 1832 and London, near
  the home of Dr. John Snow in summer of 1849

5
Broad Street Pump 1854

• Source Map 1. Published by C.F. Cheffins, Lith,
  Southhampton Buildings, London, England, 1854 in
  Snow, John. On the Mode of Communication of
  Cholera, 2nd Ed, John Churchill, New Burlington
  Street, London, England, 1855. www.
  ph.ucla.edu/epi/snow.html

6
Cholera and the Sea

• John Snow first discovered choleras mode of
  transmission waterborne
• 1883 Robert Koch isolated cholera vibrio from
  patients proved this was the agent of the
  disease
• 1961-present day Seventh pandemic. All of the
  pandemics followed coastlines of the world oceans
• The association of Vibrio cholerae with
  zooplankton has proven to be a key factor in
  understanding cholera epidemics (Colwell, 1996
  Huq et. al, 1996 Lobitz et al., 2000).

7
Copepods
source www.hsph.harvard.edu

• Microscopic view of a female copepod with
• V. cholerae attached to her egg casing

8
Cholera and Remote Sensing

• Several research groups have investigated cholera
  outbreaks indirectly by measuring phytoplankton
  blooms with satellite imagery
• Sea surface temperature (SST), sea surface height
  (SSH), and El Niño have all been considered as
  factors affecting cholera (Lobitz et al, 2000
  Pascual, 2000)
• The Bay of Bengal is a useful research region
• Five major rivers in the Indian subcontinent flow
  into the Bay of Bengal.
• Extensive data set of cholera incidence in Dhaka

9
Study Area
10
Data

• SST vs. Net heat flux UCSBs Institute for
  Computational Earth Systems Science has been
  developing a method to better estimate surface
  heat fluxes.
• International Center for Diarrheal Disease
  Research, Bangladesh, has monthly time series
  data for cholera cases.

11
Methodology

• Create a model driven by satellite remote sensing
  that more accurately accounts for interannual
  frequency of cholera cases using seasonality and
  net heat flux as predictors.
• Previous approaches
• Neural Net models
• Transient coupling

12
Conclusion

• Expect to create a more accurate fit between
  cholera incidence, ocean temperature and possibly
  ENSO
• Data sets exist
• Broad Implications
• Provide an early warning system for cholera
  outbreaks
• Cholera is a disease that can be reduced via
  simple technologies and education