Table 1.

Aedes aegypti infestation ratios (Breteau Index and pupae per person index) in function of the mean number of ITCs/house in periods with high and low ITC coverage, Laem Chabang, Thailand 2007–2008*

	October 2007 (ITC coverage = 70.5%)						October 2008 (ITC coverage = 33.2%)
	Breteau index			Pupae per person index			Breteau index			Pupae per person index
Mean no. ITCs/house	IRR	95% CI	P	IRR	95% CI	P	IRR	95% CI	P	IRR	95% CI	P
0†	1	Ref.	0.001	1	Ref.	0.09	1	Ref.	0.32	1	Ref.	0.23
> 0 and < 2 ‡	0.37	0.21–0.65		0.62	0.19–1.99		0.91	0.59–1.40		2.72	0.79–9.28
≥ 2‡	0.28	0.16–0.49		0.25	0.08–0.73		0.45	0.17–1.21		1.72	0.11–26.2

^*ITC = insecticide-treated net; IRR = incidence rate ratio; CI = confidence interval; Ref. = referent. P values were estimated by using the likelihood-ratio test.

^†Control clusters.

^‡Intervention clusters.