Transcript Water resources development and health
Impact of water resources development on health: Ghana
Francis Anto (PhD) Navrongo Health Research Centre - GHS
Navrongo Health Research Centre- Ghana Health Service
Map of Ghana showing some water development projects Tono dam Proposed Bui dam Volta Lake
Kassena-Nankana district showing the Tono dam Map of KND showing clusters in irrigated area С Paga H/C С KNE H/C Chiana H/C С W F C W F D W E A W E B W E C W E D С TB B S G S S G T TB A S G R S G Q S G N WMH S A F S A G S G M S G K S G L С S HH S HG Biu H/C S G J
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.
2.
3.
alleviating poverty promoting economic growth 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)
40 30 20 60
Fig. 1. Prevalence of Schistosomiasis in School-age children in the Kassena-Nankana district of northern Ghana, 2006
Infection S. mansoni S. haematobium 50 10 0 Overall Males Females
Categories
In-school Not-in school Overall infection was 48%, more males (52%) than females (41%) infected
p=0.002
Overall 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
60 50 40 30 20 10 0 Yes Swimming No Yes No Tomato farm
Water contact activities
Yes Rice farm No 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 Irrigated 36.7
(bite per man Non-irrigated lowland 5.9
per night ) Rocky highland 5.2
EIR (Infective bite per year) Irrigated Non-irrigated lowland 228 Rocky highland 630 360 (Appawu et al, 2004)
Table 2. Malariometric characteristics of children (<5 yrs) surveyed in KND (2001-2002)
Parameters Geographical zone Overall parasite prevalence Overall bednet use
Rural irrigated 48% 80% Rural non irrigated 56% 23% Central more urbanized 30% 34%
P-value
<0.001
<0.001
Severe anaemia (Hb<6.0g/dL) Fever (axillary temperature ≥37.5oC
All cause mortality
1.3% 8.3%
Malaria specific mortality
3.5% 9.1% 3.5% 13.3% >0.5
>0.5
100.5/1000 live births 153.7/1000 live births 26.4/1000 live births 48.4/1000 live births 95.9/1000 live births <0.05
27.7/1000 live births >0.05
80
Fig. 3. Seasonal prevalence of malaria infection in children under 5 years in rural northern Ghana by place of residence, 2001-2002
70 60 50 40 30 20 10 0 Dry season Wet season Rural non-irrigated area Dry season Wet season Rural irrigated area
Season and location
Dry season Wet season Central more urbanized 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
56 54 52 50 48 46 44 42
Fig. 4. Prevalence of parasitemia in children sleeping or not sleeping under bed nets in the KND 2001-2002
Yes bed net No bed net
Net use
Bed net was found to protect those who used them from malaria infection (
p=0.003
)
60 40 20 0 140 120 100 80 180 160
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
Allcause mortality Malaria parasitemia Rural Irrigated Central urbanized Rural non-irrigated
Area of residence
Total 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 site
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
Increased aquatic vegetation Proliferation of water snails Inundation of forest vegetation Reduction in tsetse Fly population Favourable habitat for mosquito breeding Increased malaria Prevalence Increased LF Prevalence Increased schistosomiasis Temporary reduction In incidence of trypanosomiasis Flow of the river slow down Creation of ponds Reduction in Black Fly population Proliferation of cyclops Reduction in Prevalence of River blindness Increase in Prevalence of Guinea worm Vegetative re-growth 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 region Specifically: Bilharzia Trypanosomiasis Guinea worm Intestinal worms and onchocerciasis. Health impacts may also arise in the long term owing to: the loss of medicinal plants reduced 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
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• • • • Malaria Promotion of ITNs Indoor residual spraying Schistosomiasis Annual chemotherapy (praziquantel) Mollusciciding (baylucide) • Lymphatic filariasis Annual ivermectin plus albendazole • • Guinea worm Potable water Control of cyclps (Abate) • Buruli uncer Effective community surveillance
Potential areas of research collaboration
• Malaria • Schistosomiasis • Guinea worm • Onchocerciasis • Lymphatic filariasis • Buruli ulcer • Socio-economic studies