Remotely sensed enviroclimatic patterns and ebola outbreaks linkages and early warning
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Remotely-sensed Enviroclimatic patterns and Ebola outbreaks: linkages and early warning. Dan Slayback Jorge Pinzon Compton Tucker 8 September 2004. Biospheric Science Branch, Code 923 NASA Goddard Space Flight Center Greenbelt MD 20771 USA. Outline. Ebola outbreaks: facts and hypotheses

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Remotely-sensed Enviroclimatic patterns and Ebola outbreaks: linkages and early warning

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Remotely sensed enviroclimatic patterns and ebola outbreaks linkages and early warning

Remotely-sensed Enviroclimatic patterns and Ebola outbreaks:linkages and early warning

Dan Slayback

Jorge Pinzon

Compton Tucker

8 September 2004

Biospheric Science Branch, Code 923

NASA Goddard Space Flight Center

Greenbelt MD 20771 USA


Outline

Outline

  • Ebola outbreaks: facts and hypotheses

  • Environmental links to remotely sensed data

  • Spatial & temporal specificity of environmental trigger events

  • Conclusions

From: Trigger events: enviroclimatic coupling of Ebola hemorrhagic fever outbreaks. 2004. JE Pinzon, JM Wilson, CJ Tucker, R Arthur, PB Jahrling, and P Formenty, American Journal of Tropical Medicine and Hygiene. (in press)


Remotely sensed enviroclimatic patterns and ebola outbreaks linkages and early warning

  • Many Ebola outbreaks have occurred in African closed tropical forest

  • Some Ebola outbreaks have occurred in African gallery tropical forest within a savanna matrix


Outbreak severity

Outbreak Severity

385

210

79

47


Outbreak locations

Outbreak Locations


Transmission scenarios

Transmission Scenarios

Community Epidemic Scenario

  • Secondary transmission within species.

  • Reciprocal transmission between species.

APES/HUMANS

INTERMEDIATE

HOST

RESERVOIR

Peter Walsh et al. Nature (2003)

Just because a species tests positive for virus or antibodies does not mean that it is a link in the chain of transmission to apes.

“Cul de Sac” Hosts

Cul de Sac HOST--HUMANS?

APES

RESERVOIR


Possible ebola transmission s no usual suspects

Possible Ebola Transmission(s)no usual suspects!

It is unknown where the virus dwells…


Environmental links with remotely sensed data available datasets

Environmental Links withRemotely Sensed Data:available datasets

1980

1985

1990

1995

2000

2005

2010

Moderate-resolution (1-10’s kms) environmental satellites

MODISes

NOAA-16

AVHRR

NPOESS

NOAA 14

AVHRR

NOAA 11

AVHRR

NOAA 9

AVHRR

SPOT

NOAA 7

AVHRR

SeaWiFS

NOAA9


Noaa avhrr 8 km ndvi data set

NOAA AVHRR 8-km NDVI Data Set

Radiation


Vis nir swir band comparison

VIS/NIR/SWIR Band Comparison

SPOT-VGT

SeaWiFS

AVHRR

MODIS


New improved 8 km avhrr ndvi data set 1981 present

New, improved 8-km AVHRR NDVI data set 1981-present

2003


Major dataset differences

Major Dataset Differences

Global NDVI anomalies


Are there unique environmental characteristics at outbreak sites during the outbreak year

Are there unique environmental characteristics at outbreak sites, during the outbreak year?


Hypothesis very extreme change from rainy to dry season

Hypothesis: very extreme change from rainy to dry season


1994 ebola outbreak locations ndvi time series

1994 Ebola Outbreak Locations NDVI Time Series


Mean time series and anomalies

Mean time series and anomalies


Spatial signatures and risk

Spatial signatures and risk


Canonical correlation analysis cca

Canonical Correlation Analysis (CCA)

  • CCA is a method that maximizes the variance between two datasets. Here, we use CCA to identify areas and times that exhibit enviroclimatic signals typical of those at known outbreak sites and dates.

    • CCA(A) = [U,S,V]

    • A: paired-mode correlation matrix between yearly NDVI signals and corresponding NDVI signals from the outbreak sites at outbreak years.

    • U: orthonormal vector of satellite NDVI signals

    • S: percentage of covariance explained by canonical factors

    • V: orthonormal vector of Ebola sites

  • The analysis conducted only over areas with high enviroclimatic correlation to previous outbreak sites (r2 > 0.95)


Trigger event summary

Trigger event summary


Remotely sensed enviroclimatic patterns and ebola outbreaks linkages and early warning

the hot zone


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