Table 1. S. haematobium infection characteristics stratified by survey group.

Study participants	Infection characteristics	Unguja			Pemba
		n	n pos	%	n	n pos	%
Children (1st year)	Hemastix hematuria	3,430			3,543
	0		3,313	96.6		3,014	85.1
	Trace		3	0.1		157	4.4
	+		23	0.7		78	2.2
	++		38	1.1		167	4.7
	+++		53	1.5		127	3.6
	S. haematobium eggs	3,364	174	5.2	3,533	432	12.2
	Low infection intensity		142	81.6		258	59.7
	High infection intensity		32	18.4		163	37.7
Children (9–12 years)	Hemastix hematuria	4,327			4,017
	0		4,011	92.7		3,572	88.9
	Trace		11	0.3		134	3.3
	+		98	2.3		105	2.6
	++		94	2.2		110	2.7
	+++		113	2.6		96	2.4
	S. haematobium eggs	4,262	164	3.8	4,004	326	8.1
	Low infection intensity		145	88.4		219	67.2
	High infection intensity		19	11.6		107	32.8
Adults (20–55 years)	Hemastix hematuria	2,155			1,864
	0		1,931	89.6		1,598	85.7
	Trace		50	2.3		84	4.5
	+		55	2.6		86	4.6
	++		52	2.4		67	3.6
	+++		67	3.1		29	1.6
	S. haematobium eggs	2,134	57	2.7	1,861	102	5.5
	Low infection intensity		53	93.0		95	93.1
	High infection intensity		4	7.0		7	6.9