Malaria and Water Resource Development - Recent Advances and Issues in Environmental Science - page 164

6.4% in those 5-9 years of age. The P. falciparum prevalence varied from 4.2% in
children<1 year of age to 3.8% in those 5-9 years of age.
Table 1 shows demographic, distance and temporal relationships with malaria in-
fection. The monthly P. vivax point prevalence during the 3 months ranged from 0.8%
to 10.0% and form 2.3% to 5.9% in “at-risk” and “control” villages, respectively.
Monthly P. falciparum point prevalence during the 3 months ranged from 2.7% to
6.9% and from 1.2% to 4.0% in “at-risk” and “control” villages, respectively (Ta-
ble 1). The peak prevalence rate for P. vivax was observed in October and gradually
decreased during November-December, while the prevalence rate for P. falciparum
showed a late increase in December (Figure 1).

Table 1. Demographic, distance and temporal relationships with malaria infection, Plasmodium
vivax (Pv) and Plasmodium falciparum (Pf) , in Gilgel-Gibe dam area, south-western Ethiopia, 2005.

Pv Pf

Variable Rate Crude OR (95% Cl) Rate Crude OR (95% Cl)

Age (years)

<I 'control' 4/96 (4.2%) 1 3/96 (3 . 1%) 1

'at-risk' 13/190 (6.8%) 1.69 (0.52,5.52) 9/190 (4.7%) 1.54 (0.49,4.79)

1-4 'control' 18/396 (4.5%) 1 13/396 (3.3%) 1

'at-risk' 34/429 (7.9%) 1.81 (1.21,2.71)** 23/429 (5.4%) 1.67 ( 1.42,6.66)

S-9 'control' 12/282 (4.3%) 1 1 /282 (0.4%) 1

'at-risk' 36/462 (7.8%) 1.9 (0.76,4.77) 27/462 (5.8%) 17.4 ( 1.22,249.24)**

Village/
groups'control

34/774 (4.4%) 1 17/774 (5.4%) 1

'at-risk' 8311081 (7.7%) 1.81 ( 1.17,2.79)** 59/ 1 081 (2.2%) 2.57 ( 1.0 I ,6.57)**

Month

October 'control' 1 5/253 (5.9%) 1 10/253 (4.0%) 1

'at-risk' 56/559 (1 0.0%) 1.76 (0.88,3.53)* 34/559 (6.1 %) 1.57 (0.32,7.71)

November 'control' 13/260 (5.0%) 1 3/260 ( 1.2%) 1

'at-risk' 25/262 (9.5%) 2.00 (1.38,2.92)** 7/262 (2.7%) 2.35 (0. 17,32.73)

December 'control' 6/261 (2.3%) 1 4/261 ( 1.5%) 1

'at-risk' 2/260 (0.8%) 0.33 (0.02,4.96) 18/260 ( 6. 9%) 4.78 ( 1.03,22.23) **

* = signifi cant at 0.1 level ** = signifi cant at 0.05 level

The P. vivax prevalence was signifi cantly higher in “at-risk” communities com-
pared to the “control” communities in November (OR = 2.00, 95% CI = 1.38, 2.92)
and the P. falciparum prevalence was signifi cantly higher in “at-risk” communities in
December (OR = 4.78, 95% CI = 1.03, 22.23) (Table 1). Differences between the two
communities in malaria globally ( P. vivax and P. falciparum together) were obvious
and statistically signifi cant in all months (p < 0.01).