Malaria and Water Resource Development - Recent Advances and Issues in Environmental Science - page 160

around the reservoir to reduce the prevalence of malaria. In this respect, in localities
near large dams, health impact assessment through periodic survey of potential vectors
and periodic medical screening is warranted. Moreover, strategies to mitigate predicted
negative health outcomes should be integral parts in the preparation, construction and
operational phases of future water resource development and management projects.
Malaria is one of the most important causes of morbidity and mortality in tropical
and sub-tropical countries. It is responsible for more than 1 million deaths each year
[1]. The estimated annual global incidence of clinical malaria is 500 million cases [2].
Recent estimates indicate that more than 2 billion people are exposed to malaria risk in
about 100 countries. Close to 90% of all malaria infections occur in sub-Saharan
Africa, where malaria causes an estimated 40% of fever episodes [3-5]. More than
90% of the deaths occur in children under 5 years of age in Africa [6]. Most of the
infections and deaths in highly endemic areas occur in children and pregnant women,
who have little access to health systems [7-9]. Malaria in children is complicated by
anaemia, neurological sequels from cerebral compromise, respiratory distress and sub-
optimal cognitive and behavioral development [10].
Malaria transmission varies among communities largely due to environmental fac-
tors, such as proximity to breeding sites [11]. Many water resources development and
management projects result in local outbreaks of malaria and other vector-borne dis-
eases such as schistosomiasis [12], lymphatic fi lariasis [13] and Japanese encephalitis
[14]. These outbreaks can be attributed to an increase in the number of breeding sites
for mosquitoes, an extended breeding season and longevity of mosquitoes, relocation
of local populations to high-risk reservoir shorelines and the arrival of migrant popula-
tions seeking a livelihood around the newly created reservoirs [15-19].
In Ethiopia, approximately 75% of the total area is estimated to be malarious, with
68% of the total population (52 million people) being at risk of infection [16]. Ac-
cording to the national health services statistics, malaria is among the top 10 leading
causes of morbidity [16]. Proximity to micro-dams which were constructed for small
irrigation development schemes is considered as one of the risk factors for increased
malaria incidence [18-20]. The actual malaria cases that occur annually throughout
the country are estimated to be 4-5 million [21]. Malaria is responsible for 30-40%
of outpatient visits to health facilities, 10-20% of hospital admissions and 10-40% of
severe cases in children under 5 years of age [22]. Most transmission takes place fol-
lowing cessation of rains [23]. Previous studies showed that malaria was more preva-
lent in villages that were close to small irrigation dams than in those farther away [19,
20]. Ethiopia plans to increase its electricity power supply by 5-fold over the next 5
years based on large hydropower dams to fulfi ll the needs of its people and support the
economic growth based on large hydropower dams [24]. Ethiopia's power security is
already over 85% dependent on hydropower and could grow to over 95% depending
on whether all hydropower dams under construction are commissioned. Eight hydro-
power dams account for over 85% of Ethiopia's existing 767 MW generating capacity.
Five additional hydropower sites with a combined capacity of 3,125 MW are currently
under construction. Thus, it is important to look at a variety of impacts from the reser-
voir as it may create health problems and diseases such as malaria, schistosomiasis and