Background
Methods
Study area
Mosquito collections and maintenance
Insecticide susceptibility tests
-
Pyrethroids: permethrin (0.75%), deltamethrin (0.05%) and α-cypermethrin 0.05%;
-
Pseudo-pyrethroid: etofenprox (0.05%);
-
Organochlorides: DDT (4%) and dieldrin (4%);
-
Carbamates: carbosulfan (0.4%) and bendiocarb (0.1%);
-
Organophosphates: fenitrothion (1%) and the pirimiphos-methyl (1%).
Identification of sibling species and Anopheles gambiae s.s M and S molecular forms
PCR detection of the L1014F and L1014S kdr and ace-1 R mutations
Biochemical analysis
Data analysis
Results
Bioassays
Knock-down effect
Insecticide | Strain | N | KdT50(CI95) | KdT95(min) | RR50 | RR95 |
---|---|---|---|---|---|---|
DDT 4% | Kisumu | 101 | 15.4 (12.8-18.5) | 19.5 (14.1-27.1) | _ | _ |
M’Bé | 193 | NA | NA | NA | NA | |
DDT 4% + PBO
|
M’Bé
|
105
|
NA
|
NA
|
NA
|
NA
|
Permethrin 0.75% | Kisumu | 101 | 17.3 (16.3-18.4) | 23.9 (21.8-28.1) | _ | _ |
M’Bé | 201 | 83.1 (73.9-99.2) | 204.7 (155.7-313.7) | 4.8 (4.1-5.6) | 8.6 (6.0-12.2) | |
Permethrin 0.75% + PBO
|
M’Bé
|
100
|
94.9 (76.2-134.7)
|
469.9 (276.8-1 146.7)
|
5.5 (4.1-7.2)
|
19.6 (9.9-38.5)
|
α-cypermethrin 0.05% | Kisumu | 99 | 17.8 (12.9-22.8) | 39.1 (29.2-74.1) | _ | _ |
M’Bé | 197 | 90.3 (75.5-118.9) | 341.6 (224.3-673.1) | 5.1 (4.2-6.1) | 8.7 (5.7-13.3) | |
α-cypermethrin 0.05% + PBO
|
M’Bé
|
106
|
28 (26.4-29.6)
|
59.4 (54.3-66.4)
|
1.6 (1.4-1.7)
|
1.5 (1.3-1.8)
|
Deltamethrin 0.05% | Kisumu | 126 | 19.6 (16.8-22.5) | 37.4 (31.3-50.4) | _ | _ |
M’Bé | 208 | 83.2 (73.6-98.3) | 274.9 (205.5-415.4) | 4.2 (3.6-4.9) | 7.4 (5.1-10.5) | |
Deltamethrin 0.05% + PBO
|
M’Bé
|
103
|
41.4 (37.9-45.7)
|
99.1 (81.7-133.3)
|
2.1 (1.9-2.3)
|
2.6 (2.2-3.2)
|
Etofenprox 0.5% | Kisumu | 105 | 24.7 (21.9-27.5) | 39.5 (34.4-49.7) | _ | _ |
M’Bé | 200 | 93.7 (80.7-116.9) | 296.5 (210.7-499.4) | 3.8 (3.1-4.6) | 7.5 (4.9-11.5) | |
Etofenprox 0.5% + PBO
|
M’Bé
|
91
|
83.2 (65.7-139.2)
|
265.1 (152.7-989.6)
|
3.4 (2.7-44.2)
|
6.7 (3.9-11.5)
|
Mortality
Bioassays after a pre-exposition to PBO
Molecular and biochemical analyses
Kisumu | M’Bé | |
---|---|---|
F(kdr-w) | - | 0.33 (226) |
F(kdr-e)
|
-
|
0.00 (226)
|
F(ace-1
R
) | - | 0.00 (226) |
α-Na
|
0.086 ±0.007
a
(40)
|
0.155 ±0.012
b
(40)
|
β-Na | 0.084 ±0.007a (40) | 0.125 ±0.017b (40) |
MFO
|
0.095 ±0.008
a
(38)
|
0.198 ±0.020
b
(36)
|
GST | 0.295 ±0.032a (40) | 0.378 ±0.085a (40) |