Table 2.

Mosquito mortality after exposure to pyrethroid insecticides using phenotypic assays, stratified by species, IRS category and insecticide.

Comparison between IRS category, stratified by species
Species	IRS category	Permethrin			Deltamethrin
		Mortality (%)	Odds ratio (95% CI)	P-value	Mortality (%)	Odds ratio (95% CI)	P-value
An. gambiae (s.s.)	No IRS	20/124 (16.1)	Reference		30/122 (24.6)	Reference
	IRS stopped	32/284 (11.3)	0.64 (0.15–2.71)	0.55	64/250 (25.6)	0.66 (0.19–2.33)	0.52
An. arabiensis	No IRS	86/127 (67.7)	Reference		123/147 (83.7)	Reference
	IRS stopped	82/129 (63.6)	0.90 (0.28–2.94)	0.86	120/135 (88.9)	1.37 (0.51–3.64)	0.53
	IRS active	234/358 (65.4)	1.39 (0.47–4.10)	0.55	267/337 (79.2)	0.83 (0.37–1.87)	0.66
Comparison between mosquito species, stratified by IRS category
IRS category	Species	Permethrin			Deltamethrin
		Mortality (%)	Odds ratio (95% CI)	P-value	Mortality (%)	Odds ratio (95% CI)	P-value
No IRS	An. arabiensis	86/127 (67.7)	Reference		123/147 (83.7)	Reference
	An. gambiae (s.s.)	20/124 (16.1)	0.10 (0.05–0.19)	< 0.001	30/122 (24.6)	0.06 (0.03–0.12)	< 0.001
IRS stopped	An. arabiensis	82/129 (63.6)	Reference		120/135 (88.9)	Reference
	An. gambiae (s.s.)	32/284 (11.3)	0.20 (0.10–0.38)	< 0.001	64/250 (25.6)	0.08 (0.03–0.18)	< 0.001
Comparison between insecticides, stratified by IRS category
IRS category	Insecticide	An. gambiae (s.s.)			An. arabiensis
		Mortality (%)	Odds ratio (95% CI)	P-value	Mortality (%)	Odds ratio (95% CI)	P-value
No IRS	Deltamethrin	30/122 (24.6)	Reference		123/147 (83.7)	Reference
	Permethrin	20/124 (16.1)	0.59 (0.31–1.11)	0.10	86/127 (67.7)	0.40 (0.22–0.72)	0.002
IRS stopped	Deltamethrin	64/250 (25.6)	Reference		120/135 (88.9)	Reference
	Permethrin	32/284 (11.3)	0.44 (0.27–0.71)	0.001	82/129 (63.6)	0.21 (0.11–0.41)	< 0.001
IRS active	Deltamethrin	Insufficient An. gambiae (s.s.) collected			267/337 (79.2)	Reference
	Permethrin				234/358 (65.4)	0.48 (0.34–0.68)	< 0.001