Climate Impacts on Malaria
Transmission and the Development of
an Early Warning System
Seasonal Distribution
Oct-Mar
(1961-2000)
Apr-Sep
(supported by the Climate Variability and Human Health
Program)
Lareef Zubair
International Research Institute for Climate and Society
+ many others
Partners in Collaborative Project:
–International Water Management Institute
–Anti-Malaria Campaign, Sri Lanka
–University of Kelaniya, Sri Lanka
–Columbia University Climate Group
–Land Surface Modeling Group, NASA/GSFC
–Foundation for Environment, Climate and Technology, Sri Lanka.
Malaria Burden and Poverty
Epidemiology of malaria
• Annual Average case load ~ 500,000 for
20 million persons.
• Parasites
– Plasmodium vivax (75%, 2003 – 88%)
– Plasmodium falciparum (25%, 2003 –12%)
• Vector mosquitoes
Source: Sachs, 1999
– Anopheles culicifacies
– Anopheles subpictus
– Anopheles annularis
Annual Morbidity and Mortality
(1931-2002)
10000000
1000000
10000
1000
100
10
1
Ye
a
19 r
31
19
36
19
41
19
46
19
51
19
56
19
61
19
66
19
71
19
76
19
81
19
86
19
91
19
96
20
01
Numbers
100000
Total Positives
Malaria Deaths
1
Elements of an Effective Disease Early Warning System
National Academy of Science, Institute of Medicine - Public Health Systems and
Emerging Infections, 2000
Risk analysis,
Vulnerability
Assessment
Climate forecasts
Epidemiological
surveillance
Predictive
models
Disease watch
Early warning
Environmental
observation
Response
strategy
Public
communication
Evaluation and
feedback
Malaria and Food Insecurity
0 - 1.25
1.25 - 2.5
2.5 - 5
5 - 10
10 - 20
20 - 40
40 - 80
80 - 160
>160
No Data
Workshop on “The development of
an early warning system”
Annual Temperature and Rainfall
09th December 2003
Uva Management Development Training Institute, Passara
Regional Malaria Officers,
Department of Health,
Provincial government,
University researchers,
Department of Meteorology
Aurelia Micko/OGP
Micko/OGP
2
Population and Annual Parasite Incidence
Gill, 1936
HURULUWEWA, SRI LANKA
Amerasinghe et al
• Watershed forest and
ancient tank-cascade
rice and slash-and-burn
agricultural system
• 3000 people live in the
watershed area within 3
km. of the stream
Research in 1994-1999 established
that the Yan oya stream was the
major malaria vector breeding
habitat
<Mosquito generation times [>Pop. growth rate]
<Mosquito survivorship [<Life expectancy]
<Extrinsic incubation period of virus [>Transmission rate]
Water
>Mosquito oviposition and larval habitats
>Mosquito population size [immediate]
>Vertebrate host population size [time delay]
CURRENT WATER FLOW PATTERN: SIMULATION-1
250
StreamWater Depth (cm)
Temperature
STREAM
STREAMFLOW
FLOWand
andLARVAE
LARVAE
90
CURRENT
FLOW
Stream water depth
200
Larval abundance
80
70
60
150
50
40
100
30
20
50
Larval Abundance
CLIMATE FACTORS
IN MOSQUITO-BORNE VIRUS
TRANSMISSION
10
0
0
O
1996
N
D
J
F
M
A
M
J
J
A
S
1997
Amerasinghe
et al.
Relative Humidity
>Survivorship
3
400
Streams and Model Basins
All Years
El Nino
La Nina
Rainfall
300
Rainfall
Climatology
and ENSO phases
200
100
0
J
F
M
A
M
J
J
A
S
O
N
D
Month
Rainfall
Climatology
during Epidemics
and
Other Times
Annual NINO3.4 with Epidemic
Years in Red
Modeled
Discharge at
Peradeniya
Modeled
Seasonal Soil
Moisture
Year-Latitude Correlations for Summer
Rainfall and Equatorial SST
Downscaling
With Ward, Ndiaye, Chandimala
and Perera
1600
1400
1200
1000
800
600
400
200
0
1980
Observation grd147
Forecast grd147
1985
1990
1995
2000
Zubair and Chandimala, JHM, 2006.
4
What have we learned?
• Climate related information is useful.
– Ecosystems can be responsive to climate.
– Need to work at relevant time scale
• Weather/Climate information is needed.
• In-depth place-specific, fine-scale hydro-meteorological
information and research needed.
• Climate information has to be transformed to the salient
attributes incorporating environmental, epidemiological
and vulnerability information
• Partnership, technology development.
• This work is labor intensive.
IRI’s Mahaweli River Basin Projects
January 2000 onwards
http://iri.columbia.edu/~mahaweli
5