Table 2. Control efficacy on prevalence rate in the study areas according to age and treatment strategy.

Endemicity	Treatment Strategies	Age	No. of Subjects Cs-Tested in 2003	Cs Prevalence Rates in 2001 (%) 1	Cs Prevalence Rates in 2004 (%) 1	Control Efficacy between 2001 and 2004	p-Value 2
Heavy			9346	58.3	18.8	67.8
	MT2	Total	1938	69.5	18.8	72.9
		−19	226	50.4	17.8	64.7	0.09
		20–39	916	73.9	20.2	72.7	0.09
		40–59	707	69.0	17.4	73.8	0.45
		60+	89	64.5	18.2	71.8	0.10
	MT1	Total	1745	48.0	8.4	82.5
		−19	424	31.7	9.9	68.8	0.99
		20–39	709	45.6	8.7	80.9	<0.01
		40–59	547	52.6	8.1	84.6	<0.01
		60+	65	54.9	6.4	88.3	0.02
	ST1	Total	1778	54.9	15.0	72.7
		−19	424	30.0	9.6	68.0	reference
		20–39	723	53.2	14.8	72.2	reference
		40–59	541	61.7	15.2	75.4	reference
		60+	90	54.1	20.5	62.1	reference
	ST1R	Total	1825	73.2	12.3	83.2
		−19	298	46.9	9.9	78.9	0.049
		20–39	811	71.5	11.1	84.5	<0.01
		40–59	646	78.5	14.4	81.7	0.045
		60+	70	70.3	4.5	93.6	<0.01
	ST6M	Total	2060	59.5	7.5	87.4
		−19	273	43.0	5.8	86.5	0.02
		20–39	907	57.6	6.4	88.9	<0.01
		40–59	763	62.0	7.5	87.9	<0.01
		60+	117	65.0	9.4	86.6	0.02
Moderate	ST1-mod or ST2-mod	Total	3511	26.0	1.4	94.6
		−19	358	4.7	0	100
		20–39	1417	20.0	1.1	94.5
		40–59	1522	35.3	2.2	93.8
		60+	214	19.7	0.5	97.5

MT2, mass treatment every 2 year; MT1, mass treatment every year; ST1, selective treatment every year; ST1R, selective treatment and reservoir control every year; ST6M, selective treatment every 6 month; ST2-mod, selective treatment every 2 year; ST1-mod, selective treatment every year.

¹Age specific CS prevalence rate (PR) for 1 year.

² p-value for group difference among the specific age groups with each strategy in heavy endemic areas.