This document summarizes a study on the impacts of climate change on health in Bangladesh. It will (1) study the association between salinity in drinking water and hypertension, (2) monitor changes in crop production and migration patterns in coastal areas experiencing salinity issues, and (3) supplement disease surveillance work to detect potential expansions of malaria, dengue fever, and kala azar ranges. The study aims to better understand how climate change may be exacerbating health issues in Bangladesh.

1. “Climate change is the biggest global
health threat of the 21st century”
The Lancet Commissions
Climate Change and
Health in Bangladesh
Peter Kim Streatfield
Director, Centre for Population, Urbanization and Climate Change
ICDDR,B
1

2. Framework for
CC-Health
Research - WHO

3. Direct Health Impacts
• Infectious diseases
– Malaria
– Dengue fever
– Kala Azar
– Cholera
• Other mechanisms
– Heat stress
– Others

4. Malaria:
• 14.7 million people at risk.
• 37 deaths reported by MOHFW
in 2010, but “actual cases may
be 5,000-10,000”.
• Africa shows evidence of
climate affecting malaria after
heavy rain, but South America
does not.
• Parasite prefers 24-26C temp
(reproduction rate double vs
20C), mosquitoes like similar
range. So what impact will
climate change have?

5. Dengue Fever
• 500 cases (& 0 deaths) in
2007, down from 6,000
(58 deaths ) in 2002
• An increase of 3-4oC may
double the reproduction
rate of dengue virus
• Outbreaks every 2 year
since 2000, (see graph)
• No vaccine, no specific
treatment, need to
control Aedes aegypti
mosquito.

6. Kala Azar
• Now in 105 Upazilas (up from 8 in 1981-85).
• 15-30 deaths p.a. , tho’ only 1 reported in 2010.
• “Surveillance weak, est. cases about 45,000”
• Female sandfly carries the parasitic protozoa
(Leishmania donovani).
• Favours habitats near embankments.
• Prevalence expected to increase with warming.

7. Cholera Blue-green algae
Copepod
• Discovery of marine reservoir of the cholera pathogen
in blue-green algae and copepods helps to explain the
endemicity in the Ganges delta in Bangladesh.
• A Bangladesh study found that V. cholera 01 increases
with copepods (which feed on phytoplankton) in
coastal waters. The timing of cholera outbreaks
matches (with lag) the frequency of El Nino.
7

8. Heat Stress
• Globally, cities are experiencing “urban heat
island effect”, with higher temperatures than
surroundings.
• Consequences:
– Heat exhaustion (heat stroke)
– Reduced work capacity and outputs
– Dehydration
• New studies by Tord Kjellstrom and WHO

9. Infra-red image of Western Europe, August 2003,
when a heatwave resulted in an additional
35,000+ deaths in France alone, mostly elderly
people. Temperatures were 40oC+
(brown colour) for 7 continuous days
9

10. Trends in numbers of ‘Very Hot Days’ (35oC+) shows 400%
increase over 26 years in Matlab, Chandpur.
- Methodology difficult to study impact on human labour
- This is threshold temperature for germination of rice and wheat.
Very Hot Days 35.0+C
30
25
y = 0.5679x + 4.373
R2 = 0.3005
20
15
10
5
0
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
10

11. Salinity
• Salinity moves inland up to 200
kms. in dry season. In
monsoon, salinity is pushed
back south. Overall moving N
• Links with hypertension and
pre-eclampsia in pregnant
women, and maybe other
people
• Widespread land damage has
occurred. Mass outmigration.
• We need to monitor water and
crop soils in coastal districts

12. Water towers of Asia – the glacier-fed rivers from the Tibetan
Plateau influence the lives of 40% of the world’s population
(Indus, Ganges, Brahmaputra, Mekong, Irrawaddy, Yangtze).
China have started to dam the Brahmaputra to provide power,
and may divert water to northern dry areas of China
12

13. Likely consequences of less water from
the Himalayan rivers into Bangladesh
• In monsoon, Bangladesh receives 1,100 cu. kms. water,
enough to cover entire country to 7+ metres depth. But we
lose 98% of it as difficult to construct dams and capture
water in a delta.
• Because of impending water shortages: “We’re talking
about the return to large-scale famines in developing
countries” Louis Verchot, World Agroforestry Centre, Kenya
Boys playing soccer in dry Ganges River,
Rajshahi, Bangladesh ,June 2011
13

14. Sea Level Rise (SLR)
• In predicting SLR, the IPCC
AR4 only took account of
thermal expansion of the
oceans (18-59 cms).
• Did not allow for melting
ice caps, and glaciers (now
expect 80-200 cms+).
• Melting of large ice
shelves in Antarctica
(e.g., WAIS) could produce
several metres of SLR. • SLR in Indian ocean expected
to be close to global average
of 3 mm/yr (1993-2003).
New crack in
Pine Island
Glacier,
14
Antarctica

15. Migration within
Bangladesh is partly
driven by ecological
change reducing
agricultural
production
Between 2001 & 2011,
zero population growth in
Barisal Division (green
area), and little in Khulna,
due to outmigration
(225,000 from Barisal and
125,000 from Khulna p.a.)
Many of these people
living in slums in Dhaka

16. 'Mega' Countries with Population >100 million
3000
Population Density (/sq. mile)
Bangladesh (=1,001 / sq.km.)
2500
2000
1500
Japan Pakistan
1000
Nigeria Indonesia India
500
USA China
0
0 200 400 600 800 1000 1200 1400
Mexico Brazil Population (Millions)
Russia
16

17. •Bangladesh is relatively less urbanized at 25%.
•This 34 m. urban population will triple this century
•1.5 to 2.0 m. per year migrating to cities
•Urban populations are 1/3rd slum. Overall urban pops growing at
3.5% pa (20 years doubling time), but slums at 7% (10 yrs)
•Pop densities:
–rural = 800/sq.km.;
–urban = 24,000/sq.km. (x30);
–slums = 205,000/sq.km. (x300)
–Is there a ‘heat island effect’? WHO Hothaps study suggests ‘Yes’
17

18. In a 3 country study of adaptation, we are following
ecological migrants who have lost their villages beside
the Meghna River in Matlab.
Some move to the CHT – there is a new village called Matlab.
May contribute to bringing malaria down to lowlands again.
Some move to the cities. Some to the Meghna-Dhonagoda
embankment (a), at least temporarily.
These farmers migrated to char in middle of Meghna River (b).
(a) (b)

19. Thank You

20. This study will (1/3):
• Identify association between
salinity in drinking water and
hypertension in coastal districts
– Select sample of 2,000 HHs in a south
to north strip with salinity levels from
high to low (16+ to 2 dS/m, 2009).
All selected HHs must use tubewell for
drinking water, must have been
resident in area for at least 5 years.
Test water samples.
– Select 1 child and 2 adults from each
HH to measure BP.
– Take medical and treatment history if
hypertension is known.

21. This study will (2/3):
• Establish system for monitoring changes in crop
production in coastal areas with high salinity
– Use secondary sources for trends in crop production
– Obtain data on soil salinity over time (CEGIS, others)
• Strengthen migration surveillance systems of NGOs
in ARCAB Network who work in coastal districts to
monitor rural to urban migration (urbanization).
– Obtain mobile numbers to track outgoing families.
– Conduct telephone interviews to determine if
outmigration was linked to local conditions (unproductive
farmlands, etc.).
• Link decision to outmigrate to local conditions
(income, farm production, employment, etc.)

22. This study will (3/3):
• Supplement ICDDR,B malaria surveillance in
Bandarban to detect possible expansion of range of
vectors and disease (with Dr. Wasif Ali Khan).
– Explore role of ‘Jhum’ cultivation and deforestation in
increasing habitat of malaria vector (anopheles mosquito)
and thereby expanding range of vector
• Supplement ongoing studies of Dengue Fever and
Kala Azar to detect possible expansion of range and
diseases (with Dr. Kazi Mizanur Rahman, Dr. Dinesh Mondal).