Transcript The Threat of Dengue Fever Assessment of Impacts and Adaptation to Climate Change in Human Health in the Caribbean An AIACC Project at The.

The Threat of Dengue Fever Assessment of Impacts and
Adaptation to Climate Change in
Human Health in the Caribbean
An AIACC Project at
The University of the West Indies,
Mona and Caribbean
Epidemiology Centre
Dengue in the Caribbean and El Nino years and
year after an El Nino - El Nino +1
El Nino
El Nino + 1
The Culprit (Vector)
Also the dengue mosquito
The Problem
The water problem:
•In times of rain, pools of
water collect in providing
breeding habitats.
The water storage
problem
•In dry periods, water is
stored in open containers
which provide breeding
habitats
The Temperature Problem:
•The extrinsic incubation period (EIP)
(period of incubation of parasite inside the vector)
shortens at higher temperature
•Focks et al (1995) - dengue type 2 has an EIP of
12 days at 30○ C but only 7 days at 32-35○ C.
•Koopman et al. (1991) - decreasing the
incubation period by 5 days can lead to a
threefold higher transmission rate of dengue.
The Temperature Problem (Cont.):
•Higher temperatures increase the amount of
feeding and the probability of dengue
transmission to new hosts.
•Moderately high temperatures hasten the larval
stage, leading to smaller mosquitoes, which then
require more frequent blood meal.
•Increased temperature also enhance metabolism.
The El Nino Problem:
•Taylor (1999) - El Niño years in the Caribbean
produce drier than normal conditions in the latter half
of the year
• Drying tendancy was also reported by others,
including Ropelewski and Halpart (1996)
The above leads to the storing of water problem
•The air temperature increases during El Niño
conditions in the Caribbean (Malmgren et al, 1998).
This leads to the temperature problem.
•Chen et al (1997), Taylor (1999), Chen and Taylor
(2001) showed how rainfall and temperature increases
during May to July in the El Niño + 1 year
This leads to the temperature and water problem.
The Climate Change Problem:
•Santer (2001): mean temperature increase of up to 2ºC is
projected for Caribbean after 70 years of CO2 doubling.
•Expected modulation of temperature by future El Niño
events will further enhance above increase periodically.
• Timmermann et al (1999) found an increase in El Niño
frequency in a climate model forced by future greenhouse
warming.
All the above lead to the temperature problem
•IPCC (1998): likely alteration of the global distribution of
dengue due to climate change, with 2.5 billion at risk in the
tropics and sub tropics.
The Project
The Threat of Dengue Fever
AIACC in Human Health in the Caribbean
Objectives:
•to determine the extent of the association between
climate and the incidence of dengue across the
Caribbean region;
•to identify and evaluate adaptive options to
ameliorate the impact of climate on this disease;
•to use the knowledge gained above to determine
future impacts (long term - next 50 -100 yrs) and
adaptation based on global change scenarios;
•to make the knowledge gained accessible and
useful to decision makers.
Co-Principal Investigators:
A. Anthony Chen, Atmospheric Physicist
Dept of Physics, University of the West Indies (UWI), Mona,Jamaica
Samuel C. Rawlins, Entomologist/Parasitologist
Caribbean Epidemiology Centre (CAREC),Trinidad & Tobago
Responsible Institution: UWI, Mona
UWI Team:
A. Dharmeratne Amarakoon, Physicist
Wilma Bailey, Health Geographer
Albert Owino, Meteorologist
Michael A. Taylor, Meteorologist
CAREC Team:
Karen Polson, Epidemiologist
Others
• Dave Chadee, Ministry of Health, T&T
and UWI Department of Life Science,
St. Augustine
• Rohit Doon, Ministry of Health, T&T
• Karen Webster, Sherine Huntley,
Ministry of Health, Ja.
Post Graduate Students
• Rainaldo Crosbourne, Data base
management
• Charmaine Heslop-Thomas, Medical
Geography
• Cassandra Rhoden, Scenario
generation
• Roxann Stennett, Impact Studies
Consultants:
Dr. Joan L. Aron1, Science Communication Studies
Prof. Ulisses E.C. Confalonieri2, Fundacao Oswaldo
Cruz
Dr. Henry F. Diaz3, NOAA/CDC
Dr. Roger Pulwarty3, NOAA
Dr. Benjamin D. Santer4, Lawrence Livermore National
Laboratory
Dr. Neil Ward5, International Research Institute
Dr. Tom Wigley5, National Center for Atmospheric
Research
Dr. Rob L. Wilby5, King’s College, London
1. Mathematical Modeller, 2.Epidemiologist, 3.
Climatologist
4. Atmospheric Physicist, 5. Climate Modeller
Methodology in Epidemiology
•Development of historical epidemiology database
managed by CAREC and collection of current
Dengue/ dengue haemorrhagic fever (DHF) data.
•Retrospective studies of the disease in the last 15
years
•past climate association with dengue fever
•Prospective studies carried out in the first two and
half years of the project on Vector abundance,
climate and dengue occurrence.
Methodology in Climate:
•Development of climate database managed by
CSGM and collection of current data
•Generating future climate change scenarios.
>Using statistical downscaling techniques to
regionalize climate change projections from
global climate models (GCM’s) that use
Special Report Emission Scenarios (SRES) as
inputs
> PC-based Statistical Downscaling Model
(SDSM) [Wilby et al, 2001],
Assessment of Impact and Adaptation Strategies
• Socio-economic study
 identify the socio-economic groups most atrisk for infection;
estimate the ability to respond
•Knowledge, Attitude and Practices (KAP) survey
 population's perception of climate change
impacting on dengue;
readiness of the community to modify vector
production behaviour, based on the forecast of
conditions favourable to vector and disease increase.
Recommendations for Adaptation
• Analysis of adaptation strategies
based on impact and scenario
studies
• Early warning system
Results: Retrospective Study
1
Moving Average Temperature (MAT) =
M
M
T
N
N 1
TN is the average temperature during the Nth 4 week period
or month
M = 1, 2, 3,…13 or 12.
Examples:
For
1st
For
2nd
For
4th
4 week period or
1st
MAT 
month, M=1 and
period or month, M=2 and
1
MAT 
period or month M= 4 and MAT 
T1
1
2
1
4
T1  T 2 
T1  T 2  T3  T 4 
Results: Prospective Study
Qualitative model of the first prospective year (2002):
distribution of dengue cases, vector density and climate
(Trinidad)
1600
1400
1200
1000
800
600
400
200
0
25
20
15
10
5
0
J
F M A M J
J
Months
A S O N D
Aedes aegypti index
No. dengue cases
rainfall
Dengue Cases
Rainfall
Breteau index
Results: Socio-economic Study
Results: KAP Survey
Results: Scenario generation: Ja. Temperature
Scenario generation: Barbados Precip
Consequences
• Increase in temperature of about 2ºC
expected by 2080
• Not much change in precipitation
expected
• 2ºC is expected to give rise to a 3fold increase in the rate of
transmission of dengue
Early crossing of Avg. MAT in
1998 associated with early
onset; slow approach in 1997
assocated with late onset;
crossing in 1996 and 2000
coincides with onset
Early Warning
using MAT
index:
RC, Moving Average T vs 4-Week periods (1996, 1997, 1998, & 2000) T&T
900
Reported Cases (RC)-4 WEEKLY
29
RC-1996
RC-1997
RC-1998
RC-2000
MAT-1996
MAT-1997
MAT-1998
MAT-2000
27.2 C Lline
800
700
600
28.75
28.5
28.25
28
27.75
27.5
500
27.25
27
400
26.75
300
26.5
200
26.25
26
100
25.75
0
25.5
1
2
3
4
5
6
7
8
4-WEEK PERIODS
9
10
11
12
13
MAT in C
1000
Avg MAT
Early Warning System for Dengue
Epidemic
Check List:
Climate Surveillance
MAT index
Epidemiology Control (Surveillance)
Breteau index
Pupae/person Index
Presence of dengue below epidemic
level
Response within means
MAT
• The time the average MAT is
approached or reached can be used
to gauge the potential for the onset
of an epidemic
– An analog approach can be used
• Especially useful for timing early or
late epidemic
• Easiest of items on check list to
monitor
• Next step – remaining items on
check list
Adaptation: Short and long term measures
MEASURES
C
o
s
t
Effectiveness
Social
acceptability
Friendly
for
environment
Neighbour
effects
Technical
challenges
and
socioeconomic
change
Sco
re
H
L
L
L
L
H
6
2.
Education
(disease
symptoms,
sanitizing
the
environment).
M
M
H
H
H
M
24
3. Surveillance for vector or
larval/pupal control.
H
M
M
M
M
L
18
1. Surveillance for vector or
larval/pupal
control
and
environmental sanitation
H
M
M
M
L
L
16
2. Community education and
involvement.
M
H
H
H
H
M
26
3. Chemical control
H
M
M
L
M
L
16
4. Biological control
H
H
M
H
M
M
20
- Physical-mesh windows
M
H
H
H
H
H
24
- Personal protection
M
M
M
M
M
H
16
H
H
M
H
H
H
20
7. Granting security of tenure
to squatters
H
H
H
M
H
H
20
8. Early warning system
M
H
H
H
H
H
24
Short term
1.
Adulticide
(ULV
or
thermal fog sprays) in truck
or air
Long Term
5. Adult Control
6. Use of physical controllow cost secure drums
Weighting Low - 1, Medium -2 High – 3
Reversed for Cost and Technical Challenge
Assignment based on expert opinion (MOH’s)
MEASURES
C Effectiveo ness
s
t
Social
acceptability
Friendly
for
environment
Neighbour
effects
Technical
challenges
and socioeconomic
change
Sco
re
H L
L
L
L
H
6
2.
Education
(disease
symptoms, sanitizing the
environment).
M M
H
H
H
M
24
3. Surveillance for vector or
larval/pupal control.
H M
M
M
M
L
18
Short term
1. Adulticide (ULV or
thermal fog sprays) in truck
or air
Long Term
3. Surveillance for vector or
larval/pupal control.
H M
M
M
M
L
18
1. Surveillance for vector or
larval/pupal control and
environmental sanitation
H M
M
M
L
L
16
2. Community education and
involvement.
M H
H
H
H
M
26
3. Chemical control
H M
M
L
M
L
16
4. Biological control
H H
M
H
M
M
20
- Physical-mesh windows
M H
H
H
H
H
24
- Personal protection
M M
M
M
M
H
16
6. Use of physical control- H H
low cost secure drums
M
H
H
H
20
Long Term
5. Adult Control
7. Granting security of tenure
to squatters
H H
H
M
H
H
20
8. Early warning system
M H
H
H
H
H
24
Climate Change and biodiversity
• How will climate change?
IPCC: The World Meteorological Organization (WMO)
and the United Nations Environment Programme
(UNEP) established the Intergovernmental Panel on
Climate Change (IPCC) in 1988.
.
The IPCC has three Working Groups and a Task Force
Working Group I assesses the scientific aspects of
the climate system and climate change.
Working Group II assesses the vulnerability of socioeconomic and natural systems to climate change,
negative and positive consequences of climate
change, and options for adapting to it.
Working Group III assesses options for limiting
greenhouse gas emissions and otherwise mitigating
climate change.
Summary for Policy
Makers
(Global Projections
Working Group 1)
FINAL FIGURES & TABLES
FROM PLENARY
Updated:
20 Feb 2007
Conclusions about projected climate change for
Caribbean region:
• Sea levels will likely continue to rise on average
during the century around the islands of the
Caribbean Sea. (Models indicate that the rise
will not be geographically uniform globally but
large deviations among models make estimates
of distribution across the Caribbean, Indian and
Pacific Oceans uncertain.)
• All Caribbean islands are very likely to warm
during this century. The warming is likely to be
somewhat smaller than the global, annual mean
warming in all seasons.
• Rainfall in the vicinity of the Greater Antilles is
likely to decrease in JJA but changes elsewhere
and in DJF are uncertain.
For More details
• Climate Change Conference at UWI
• June
Climate
Change and
Biodiversity
Some topics in biodiversity
•
•
•
•
•
•
•
•
•
•
•
•
Loss of habitat
Shift in Ecological Zones
Erosion of beaches
Inundation of coastal lands
Cost to protect coastal community
Fisheries
Declining area for turtle nesting
Change in forestation
Forest Health and productivity
Carbon sequestration
Modelling
Adaptation