Control of pyrethroid and DDT-resistant Anopheles gambiae by application of indoor residual spraying or mosquito nets treated with a long-lasting organophosphate insecticide, chlorpyrifos-methyl

Table 1 Summary results of mosquitoes hut frequenting habit and exit rates in huts.

	Total entered	Average per night	Actual number fed	(%) personnel protection	% exiting (CI)
ITNs
Anopheles gambiae s.s.
Untreated net	689^a	17.2	572	-	25.0^a (21.7-28.2)
LC	386^b	9.7	317	44.6	29.0^a (24.5-33.5)
CM	648^a	16.2	518	9.4	34.2^a (31.5-39.2)
Culex quinquefasciatus
Untreated net	845^a	21.1	531	-	29.8^a (26.7-32.9)
LC	598^b	14.9	355	33.1	35.9^a (32.1-39.8)
CM	839^a	21.0	487	8.3	34.0^a (30.6-37.1)
IRS
Anopheles. gambiae s.s.
Unsprayed hut	203^a	5.1	178	-	45.8^a (39.8-52.7)
LC	117^a	2.9	86	51.7	58.1^b (49.2-67.1)
CM	420^b	10.5	336	0	50.5^a (43.4-58.5)
DDT	268^a	6.7	201	0	41.3^a (36.0-47.7)
Culex quinquefasciatus
Unsprayed hut	858^a	21.4	730	-	52.7^a (49.3-56.0)
LC	769^a	19.2	330	54.8	54.6^a (51.1-58.1)
CM	817^a	20.4	621	14.9	51.0^a (47.6-55.2)
DDT	764^a	19.1	535	26.7	49.7^a (44.1-55.0)

Summary results of the impact of insecticide treated nets (ITNs) and indoor residual spray (IRS) treatments on hut frequenting habit, individual exposure to bites and exit rates of An. gambiae and Cx. quinquefasciatus to the verandahs of the huts in Ladji. For each intervention arm (ITN and IRS) and mosquito species, values in columns sharing the same letter superscript do not differ significantly. LC = Lambdacyhalothrin; CM = Chlorpyrifos methyl; DDT = Dichlorodiphenyltrichloroethane