Table 3.

Univariate analysis of behavioral and environmental characteristics for West Nile virus case-patients and control-subjects—East Valley of metropolitan Phoenix, Arizona, May 25–July 31, 2010

Characteristics	Case-patients		Control-subjects		Univariate analysis
	n/N	(%)	n/N	(%)	P value
Behavioral characteristics
Does not work or attend school outside the home	33/49	(67)	33/74	(45)	0.01
Never wears long sleeves and pants when outdoors	38/49	(78)	47/74	(64)	0.09
Never uses insect repellent when outdoors	42/49	(86)	61/74	(82)	–*
Spends ≥ 1 hour/day outdoors	31/46	(67)	42/73	(58)	–
Always uses air-conditioner	41/48	(85)	67/74	(91)	–
Keeps windows closed	36/49	(73)	59/74	(80)	–
House and yard characteristics
Water-holding containers in yard	38/41	(93)	31/44	(70)	< 0.01
House constructed before year 2000	25/49	(51)	49/74	(66)	0.09
Pool at residence	27/49	(55)	30/74	(41)	–
Deck or unscreened porch	39/41	(95)	40/44	(91)	–
Unscreened doors or windows	32/41	(78)	35/44	(80)	–
Irrigation and other environmental characteristics
Lives within 500 m of Water District X	16/49	(33)	12/74	(16)	0.03
Neglected pools within 500 m of residence reported to county	22/49	(45)	20/74	(27)	0.04
Population density ≥ 1,000/sq. miles within census block group	46/49	(94)	62/74	(84)	0.08
≥ 25% of houses vacant within census block group	8/49	(16)	5/74	(7)	0.10
Green area ≥ 10% of total area within 500 m of residence	22/49	(45)	29/74	(39)	–
Catch basins within 500 m of residence	18/31	(58)	25/38	(66)	–
Open irrigation canals within 500 m of residence	21/47	(45)	38/67	(57)	–
Flood irrigation observed within 100 m of residence	10/41	(24)	8/44	(18)	–

^*P value > 0.10.

n = number affected; N = total number.