Table 4 Association between washing practices and cone bioassay mosquito mortality ≥ 80% (results of univariable logistic regression, Section A) and log deltamethrin concentration (in g/kg netting material, by univariable linear regression, Section B)
|  | SECTION A: outcome: cone bioassay mosquito mortality ≥ 80% | SECTION B: outcome: log deltamethrin concentration (in g/kg netting material) | |||
|---|---|---|---|---|---|
n/N (%) | Odds ratio (95% CI) | n | Median (IQR) | Regression coefficient (95% CI) | |
Washing method | |||||
 LLIN not washed†| 24/56 (42.9%) | Ref | 8 | 0.22 (0.11–0.62) | Ref |
 LLIN washed by hand or with wooden bat in tub or in washing machine | 30/139 (21.6%) | 0.37 (0.19–0.72) | 25 | 0.09 (0.03–0.21) | − 0.20 (− 0.43 to 0.03) |
 P value | 0.003 | 0.0032 |  | 0.1928 | 0.0886 |
Detergent use | |||||
 LLIN washed, without soap or with non-detergent soap | 14/52 (26.9%) | Ref | 11 | 0.10 (0.03–0.24) | Ref |
 LLIN washed with (harsh) detergent | 15/81 (18.5%) | 0.62 (0.27–1.42) | 13 | 0.09 (0.04–0.19) | 0.03 (− 0.11 to 0.17) |
 P value | 0.252 | 0.2561 |  | 0.4496 | 0.6911 |
Type of water used | |||||
 Tap water | 9/41 (22.0%) | Ref | 8 | 0.07 (0.03–0.17) | Ref |
 Water from pump or well or open water source | 21/97 (21.6%) | 0.98 (0.40–2.38) | 17 | 0.10 (0.03–0.21) | 0.04 (− 0.09 to 0.17) |
 P value | 0.969 | 0.9688 |  | 0.4130 | 0.5518 |
Soaking of the LLIN | |||||
 LLIN washed, but not soaked | 9/41 (22.0%) | Ref | 7 | 0.06 (0.03–0.10) | Ref |
 LLIN soaked (< 1 h) | 19/85 (22.4%) | 1.02 (0.42–2.52) | 15 | 0.11 (0.02–0.21) | 0.05 (− 0.04 to 0.14) |
 P value | 0.959 | 0.9596 |  | 0.2847 | 0.2736 |
Drying in the sun | |||||
 Inside or outside in the shade | 13/63 (20.6%) | Ref | 10 | 0.20 (0.03–0.35) | Ref |
 Outside in the sun | 16/71 (22.5%) | 1.12 (0.49–2.56) | 13 | 0.08 (0.02–0.11) | − 0.14 (− 0.30 to 0.01) |
 P value | 0.790 | 0.7906 |  | 0.1360 | 0.0710 |