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Hydrometeorological, Entomological and Epidemiological Time Markers for

Urban Malaria in Niamey, Niger

Earle Williams

Session H36:  The Hydroclimatic Basis for Tropical Ecosystem Services

American Geophysical Union,  Fall Meeting

December 13-17, 2010

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CERMES (Niamey, Niger)Thierry Fandeur and Rabiou Labbo

Institut Pasteur (Paris, France) Jean-Bernard Duchemin

Université des Antilles et de la Guyane (Guadeloupe, France)Nathalie Nathou

AGRYMET (Niamey, Niger)Abdou Ali and Adamou Mahamadou

DMN (Niamey, Niger)Ousmane Allahi Daoura and Gaptia Lawan Katiellou

PNLP (Niamey, Niger)Salissou Adamou and Abami Maazou

SPIS (Niamey, Niger)Moussa Barké

Great Basin Unified Air Pollution Control District (Bishop, CA)Brian Russell

Collaborators

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Working Hypothesis:• Hydrometeorological aspect:  The onset of sustained standing

water is abrupt and synchronous

• Entomological aspect:  The onset of the mosquito population is abrupt and synchronous

• Epidemiological aspect:  The onset of malaria cases is abrupt and synchronous

The Nature of Malaria Development in Niamey, Niger

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Time Line for Malaria Development

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Map of Niamey, Niger Showing Locations of Public Clinics

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0 50 100 150 200 250 300 3500

50

100

Gaweye

H.D.

Karadjé

Kirkissoye

Lamordé 1

Saguia

Lamordé 2

Zarmagandey

Julian Day

0

50

100

02040

02040

0100200

0

50

100

050

100150

050

100150200

Year 2005

Abrupt and Synchronous Increase in Malaria Cases

tMalaria

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Evolution of Standing Water in One Niamey Street

15%

10%

5%

Rue Dallols – PlateauNiamey, Niger 2007

July August September

Stan

ding

Wat

er A

rea

(m2 )

Frac

tiona

l are

a (%

)

2000

1500

1000

500

0

tWater

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Standing Water in Niamey, Niger(Rue Dallols)

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Climatology of Surface Relative Humidity Over Oceans

from Peixoto and Oort (1996)

80% is a common value

At night, a land surface with standing water behaves like the ocean

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Daily Maximum Relative Humidity For 2004-2009 (Agrhymet Station, Niamey)

0 50 100 150 200 250 300 3500

20406080

100

Year 2009

Year 2008

Year 2007

Year 2006

Year 2005

Year 2004

JulianDay

Rel

ativ

e H

umid

ity (%

)

020406080

100

Rel

ativ

e H

umid

ity (%

)

020406080

100

Rel

ativ

e H

umid

ity (%

)

020406080

100

Rel

ativ

e H

umid

ity (%

)

020406080

100

R

elat

ive

Hum

idity

(%)

020406080

100

Rel

ativ

e H

umid

ity (%

)

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0 50 100 150 200 250 300 3500

20

40

60

80

100Year 2005

R

elat

ive

Hum

idity

(%)

Julian Day

HRmax HRmin

Daily Max and Min Relative Humidity For 2005 (Agrhymet Station, Niamey)

tWater

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Time Markers (tWater, tMalaria) for Seven Seasons

Year 80% RH 80% RH District I District II District III Difference (days)

(DMN) (AGRHYMET) tMalaria - tWater

2004 July 7 June 30 Aug 8 Aug 8 Aug 8 32, 39

2005 June 30 June25 Jul 24 Jul 24 Jul 24 25, 29

2006 July 15 July 9 Aug 6 Aug 6 Aug 6 21, 28

2007 July 22 July 22 Aug 21 Aug 21 Aug 21 28, 28

2008 June 25 June 25 Jul 27 Jul 27 Jul 20 25, 32

2009 July 27 July 27 Aug 15 Aug 15 Aug 15 20, 34

2010 July 28 July 30 Boukoki clinic max cases on Sept 2 36, 34

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Abrupt and Synchronous Increases in Mosquito Counts

Light Trap Measurements

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Evolution of Hydrometeorology and Mosquitoes   2010 Wet Season

tWatertMosquito tMalaria

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Value of Time Markers

Time Marker Value

tWaterFocused deployment of larvacides

tMosquitoFocused deployment of insecticides

tMalariaFocused deployment of clinic personnel and supply of medication

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• Consistent time markers have been identified in the development of urban malaria in Niamey, Niger

• Greater integration of expertise in hydrometeorology, entomology and epidemiology are needed to combat this disease

Conclusion

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Annual Deaths Due to Malaria Versus Annual Rainfall Total in Niamey, Niger

300 400 500 600 700 800 900200

300

400

500

600

1998

20022003

2004

2005

2006

Dea

ths

in N

iam

ey d

ue to

mal

aria

Annual rainfall for Aéroport gauge

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Standing Water in Niamey, Niger

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Standing Water in Niamey, Niger

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Abrupt and Synchronous Increase in Malaria Cases

20 30 40 500

50100

Week

Goudel0

100200 G.R.

080

160 Boukoki0

100200 Lazaret

080

160 Maourey0

200400600 Tondibiah

050

100 F. Kouara0

50100 Yantala Haut

050

100 Recasement

20 30 40 500

200400

Week

Goudel0

100200 G.R.

080

160 Boukoki0

100200 Lazaret

080

160 Maourey0

100200300 Tondibiah

0100200300 F. Kouara

050

100150 Yantala Haut

0100200 Recasement

20 30 40 500

4080

120

Week

Goudel0

204060 G.R.0

200400 Boukoki

0100200300 Lazaret

0100200 Maourey

0100200 Tondibiah

080

160 F. Kouara0

80160 Yantala Haut

04080

120 Recasement

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Evidence for Abrupt Increases in Mosquito Populations

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Flooding in Taladje Quartier Due to a Blocked Drain

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Aircraft Surveillance of Boukoki Gouro