A tool box for operational mosquito larval control: preliminary results and early lessons from the Urban Malaria Control Programme in Dar es Salaam, Tanzania

Table 4 Comparison of mean human biting rates (HBR) of An. gambiae s.l. and Culex sp. and entomological inoculation rate (EIR) for An. gambiae s.l. in the intervention and non-intervention wards during baseline and first year of intervention. 95% confidence intervals in parenthesis.

	Pre-Intervention^a			First intervention year^b			Percentage Reduction
	Non-Intervention Wards	Intervention Wards	p ^c	Non-Intervention Wards	Intervention Wards	p
Annual mean
Daily HBR An. gambiae	0.93 (0.60–1.46)	0.72 (0.51–1.02)	0.367	0.94 (0.57–1.56)	0.50 (0.38–0.68)	0.040	31.3%
Annual EIR An. gambiae	1.05 (0.68–1.65)	0.81 (0.58–1.15)		1.06 (0.64–1.77)	0.56 (0.43–0.77)
Daily HBR Culex sp.	173.9 (140.7–214.9)	86.8 (72.7–103.7)	<0.001	171.5 (137.2–214.3)	86.1 (70.9–104.4)	<0.001	0%
Dry season mean (July-August-September)
Daily HBR An. gambiae	0.59 (0.32–1.11)	0.46 (0.29–0.72)	0.505	1.17 (0.56–2.47)	0.12 (0.08–0.20)	<0.001	86.8%
EIR An. gambiae	0.67 (0.36–1.26)	0.52 (0.33–0.81)		1.32 (0.63–2.79)	0.14 (0.09–0.22)
Daily HBR Culex sp.	196.3 (157.9–244.0)	98.4 (82.2–117.9)	<0.001	151.1 (125.3–192.0)	86.1 (67.1–110.6)	<0.001	0%

^a April 2005 – March 2006; March 2006 has been included in the calculation for the baseline year since reductions of adult mosquitoes due to larviciding cannot be expected earlier than 3–4 weeks into the intervention [36].
^b April 2006 – March 2007.
^c Generalized estimating equations (GEE) were used to analyse pre-intervention data and data from the first year of intervention, respectively. In each analyses mean densities are compared between non-intervention and intervention sites. Ten-cell units were used as a subject unit, log linked mosquito densities and intervention and non-intervention areas as the factor.