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Impact of water resources development on health: Ghana
Francis Anto
(PhD)
Navrongo Health Research Centre - GHS
Kassena-Nankana district showing the Tono dam
Ñ
Ñ
Ñ
Ñ
Ñ
WMH
Chiana H/C
Biu H/C
KNE H/C
Paga H/C
Map of KND showing clusters in irrigated area
SGJ
SGM
SGK
SGN
SHG
SAF
WFD
SGL
WEC
SGQ
WED
WEA
TBB
SAG
SGRSGS
WEB
TBA
WFC
SHH
SGT
Health Impact of water resources development
Programmes of water resources development and the resultant population movements are known to have worsened the transmission of schistosomiasis in countries like Ghana, Nigeria, Sudan, Brazil and the Philippines (Iarotski and Davis, 1981).
This has led to an increase in both prevalence and intensity of infection.
Health Impact of water resources development cont.
Water resources development has become increasingly important in African countries including Ghana
Although improved hydraulic infrastructure holds potential for:
1. alleviating poverty2. promoting economic growth3. improving food security and mitigating floods,
adverse health effects may undermine these objectives (Hunter et al. 1993; Jobin 1999; Keiser et al. 2005), if the appropriate measures are not put in place
Impact of the Tono irrigation system on health
The largest irrigation system in Ghana (Tono irrigation system-ICOUR) is located in the Kassena-Nankana district of the upper east region
The region has about 144 small dams and 70 dug-outs These water development schemes have worsened the
schistosomiasis burden of the region (Scott, 1977; Amankwa, et al., 1994; Hunter, 2003)
Leading to a prevalence level of about 70% among school-age children living along the Tono irrigation canals (Amankwa, et al., 1994)
Fig. 1. Prevalence of Schistosomiasis in School-age children in the Kassena-Nankana district of northern Ghana, 2006
0
10
20
30
40
50
60
Overall Males Females In-school Not-in school
Categories
% i
nfe
cti
on
le
ve
ls
Infection
S. mansoni
S. haematobium
Overall infection was 48%, more males (52%) than females (41%) infected p=0.002Overall infection in in-school children similar to those not in-school
Fig. 2. Prevalence of schistosomiasis in school-age children in the Kassena-Nankana district of northern Ghana in relation to water
contact activities, 2006
0
10
20
30
40
50
60
Yes No Yes No Yes No
Swimming Tomato farm Rice farm
Water contact activities
% i
nfe
cti
on
levels
71% swim in canals, 60% wash items in canals, More swimmers (p=0.004) than non-swimmers were infected. More workers on tomato farms
(p=0.003) than non workers were infected
Table 1. Malaria transmission intensity in the Kassena-Nankana district
Geographical zone Transmission Intensity
Biting rate
(bite per man per night )
Irrigated 36.7
Non-irrigated lowland 5.9
Rocky highland 5.2
EIR
(Infective bite per year)
Irrigated 630
Non-irrigated lowland 228
Rocky highland 360(Appawu et al, 2004)
Table 2. Malariometric characteristics of children (<5 yrs) surveyed in KND (2001-2002)
Parameters Geographical zone
Rural irrigated
Rural non-irrigated
Central more urbanized
P-value
Overall parasite prevalence
48% 56% 30% <0.001
Overall bednet use 80% 23% 34% <0.001
Severe anaemia (Hb<6.0g/dL)
1.3% 3.5% 3.5% >0.5
Fever (axillary temperature ≥37.5oC
8.3% 9.1% 13.3% >0.5
All cause mortality 100.5/1000 live births
153.7/1000 live births
95.9/1000 live births
<0.05
Malaria specific mortality
26.4/1000 live births
48.4/1000 live births
27.7/1000 live births
>0.05
Fig. 3. Seasonal prevalence of malaria infection in children under 5 years in rural northern Ghana by place of residence, 2001-2002
0
10
20
30
40
50
60
70
80
Dry season Wet season Dry season Wet season Dry season Wet season
Rural non-irrigated area Rural irrigated area Central more urbanized
Season and location
Pe
rce
nta
ge
infe
cti
on
lev
els
Prevalence of infection was seasonal in rural non-irrigated area (dry=37.7%; wet 72.2%, p<0.001).The prevalence of infection in the rural irrigated (dry=41.3%; wet 55.4%, p>0.05) and central more urbanized (dry=22.6%; wet 34.3%, p>0.05) areas was not seasonal
Fig. 4. Prevalence of parasitemia in children sleeping or not sleeping under bed nets in the KND 2001-2002
42
44
46
48
50
52
54
56
Yes bed net No bed net
Net use
Pe
rce
nta
ge
of
ch
ildre
n w
ith
ma
lari
a
infe
cti
on
Bed net was found to protect those who used them from malaria infection (p=0.003)
Fig. 5. Malaria parasitemia and all cause mortality in children under 5 years of age in the Kassena-Nankana district of northern Ghana, 2001-
2002
0
20
40
60
80
100
120
140
160
180
Rural Irrigated Central urbanized Rural non-irrigated Total
Area of residence
Per
cen
tag
e o
f ch
ildre
n w
ith
m
alar
ia in
fect
ion
Allcause mortality
Malaria parasitemia
All cause mortality was highest in the rural non-irrigated area where malaria infection was also highest
Impact of Akosombo dam on health
When Ghana gained independence in 1957 from British colonial rule, it was envisioned that the Akosombo dam project was the most economical source of energy needed for the industrialization and modernization of the country
This led to an increase in prevalence of schistosomiasis from about 3% in 1961 to about 84% by 1967 in schoolchildren [upstream: Kete Krachi, and Yeji] (Paperna, 1969)
And also from about 17% in 1963 to 74.6% in 1981 [downstream: Bator](Wen and Chu 1984)
Bui dam
Having had problems with the supply of adequate electricity from Akosombo dam, for over a year now, the government of Ghana is embarking on building of another hydroelectric dam, the Bui dam.
In addition to generating electricity, there will be an irrigation system and
A modern city, the Bui city
Ecological changes with dam construction
Flow of the river slow down
Increased aquatic vegetation
Inundation of forest vegetation
Favourable habitat for
mosquito breeding
Proliferation of water snails
Increased schistosomiasis
Reduction in tsetse Fly population
Temporary reduction In incidence of
trypanosomiasis
Vegetative re-growth
Increased malaria Prevalence
Increased LF Prevalence
Creation of ponds
Proliferation of cyclops
Increase in Prevalence ofGuinea worm
Reduction in Black Fly population
Reduction in Prevalence of
River blindness
Rapid rebound of infestation
Some beneficial effects
1. Reduction in incidence of onchocerciasis
2. With the irrigation scheme, there will be improvement in food production in the long term
Current situation at the Bui site I
The health and nutritional status of the communities in the Bui project area have been described as poor
That malnutrition is pervasive with a high prevalence of infectious diseases including schistosomiasis.
There is lack of potable water and inadequate health services and facilities
Poor environmental sanitation and housing(Environmental impact assessment report)
Current situation at the Bui site II
Similar to the Volta basin, schistosomiasis is prevalent in the Bui project area (ERM report, 2007)
There is therefore a very high likelihood that the prevalence and intensity of the disease will rise as a result of the development of the water project
Potential health problems (Bui) According to the EIA report:The creation of the dam will impact significantly on disease incidences
in the local regionSpecifically: BilharziaTrypanosomiasisGuinea wormIntestinal worms and onchocerciasis.
Health impacts may also arise in the long term owing to: the loss of medicinal plantsreduced food security arising from lower farm productivity and in-migration of people carrying communicable diseases
Conclusion
There is no doubt that water resources development increases the incidence of several tropical diseases
1. Dams in Cameroon (Atangana et al. 1979)
2. Kenya (Oomen 1981; Roggeri 1985)
3. Mali (King 1996)
4. Ethiopia (Lautze et al, 2007) have resulted in an increased malaria burden
5. Ghana (Wen &Chu, 1984) schistosomiasis
6. Ghana (Ampofo and Zuta,1995) Barekese dam
Recommendations
Communities closest to the reservoir appear to be the worst affected
Large water impoundments in malaria endemic parts of sub-Saharan Africa are likely to increase the force of malaria transmission
Appropriate measures need to be put in place to mitigate the impact through informed prevention strategies
This requires an integrated approach to water resources development that substantially incorporates health parameters into development plans and encourages on-going collaboration between the water and health sectors
Recommendations
1. Malaria • Promotion of ITNs• Indoor residual spraying
2. Schistosomiasis • Annual chemotherapy (praziquantel)• Mollusciciding (baylucide)
3. Lymphatic filariasis• Annual ivermectin plus albendazole
4. Guinea worm• Potable water• Control of cyclps (Abate)
5. Buruli uncer• Effective community surveillance
Potential areas of research collaboration
• Malaria
• Schistosomiasis
• Guinea worm
• Onchocerciasis
• Lymphatic filariasis
• Buruli ulcer
• Socio-economic studies