Malaria and Water Resource Development - Recent Advances and Issues in Environmental Science - page 169

P. falciparum . Plasmodium vivax was found in 117 (60.3%) children, P. falciparum
in 76 (39.2%) and mixed infection in one (0.5%) child. The other two Plasmodium
species, P. malariae and P. ovale were absent. A similar distribution (69% P. vivax and
31% P. falciparum ) was reported in a previous study [42]. But, in central Ethiopia,
Woyessa et al. [43] reported the predominance of P. falciparum during October while
P. vivax tends to dominate during November. A parasitological community-based
study conducted by Gebreyesus et al. [20] on the impact of small irrigation dams on
malaria burden in northern Ethiopia also revealed a predominance of P. falciparum .
The prevalence of malaria infections varies seasonally, with P. vivax dominating in
the dry season (March-June) and P. falciparum peaking in September-October, after
the end of the main rainy season [16]. Hence, the proportion of malaria cases due
to the two parasite species can vary across seasons and localities. Ramos et al. [44]
reported variability in the distribution of malaria parasites (22.4-54.7% P. vivax and
40.9-73.4% of P. falciparum ) during different seasons.
The classifi cation trees show that using this non-parametric technique allows
obtaining a better insight in the data structure and the available interactions be-
tween determinants in their infl uence on (or relation with) malaria. This was also
noted by Thang et al. [30]. The classifi cation tree results correspond well with the
graphical trend observations, indicating that for P. vivax , children can be grouped
according to month and children sampled in October-November showed higher
prevalences even more when children were living in “at-risk” communities (preva-
lence = 9.9%). For P. falciparum , the children living in “at-risk” communities were
grouped together because of higher prevalences. Within “at-risk” communities es-
pecially children sampled in October and December showed a higher prevalence
of 6.3%.
In conclusion, this study informs that children living in close proximity to the
reservoir created by the newly constructed Gilgel-Gibe dam are at a greater risk of
Plasmodium infection than children living further away, possibly due to the creation
of new vector habitats around the lakeshore. Epidemiological studies focusing on vec-
tor dynamics and socioeconomic, demographic and health behavior factors could be
conducted to identify underlying causes of the spatial pattern of infection reported in
this chapter.
Recommendations
In order to maximize the economic benefits generated by Gilgel-Gibe hydroelectric
dam, it is recommended that preventive programs against malaria and other vector-
borne diseases be implemented along the periphery of the reservoir. Health Package
program, including bed net use and health education, early diagnosis and treatment, re-
sidual spraying and environmental management be implemented in an integrated way
and strengthened to reduce disease burden from vector-borne diseases in communities
living in close proximity to the new reservoir.