Exploring the Molecular Basis of Insecticide Resistance in the Dengue Vector Aedes aegypti - Recent Advances and Issues in Environmental Science - page 174

Table 1. (Continued)

Strain Enzyme

inhibitor

Slope
(± SE)

LC 50
(j.tg/L)
(95% Cl)

LC 95 (j.tg/L)
(95% Cl)

RR 5o
(95% Cl)

RR 95
(95% Cl)

SR 5o (95%
Cl)

SR 95 (95%
Cl)

3.00
(0. 16)

68
(64-72)

240
(210-270)

21
(18-22)

44
(38-52)

2.37
(2.18-2.57)

4.27
(3.64-5)

DEF

1.57
( 1.39-1. 79)
Resistant ratios RR50 and RR95 were obtained by calculating the ratio between the LC50 and LC95 between Vauclin
and Bora-Bora strains; Synergism ratios SR50 and SR95 were obtained by calculating the ratio between LC50 and LC95
with and without enzyme inhibitor. (CI): Confi dence Interval. Signifi cant RR and SR are shown in bold.

2.05
(0. 11)

103
(92-110)

650
(560-790)

24
(22-27)

109
(92-129)

1.57
(1.39-1.79)

DMC

Topical applications of the pyrethroid insecticide deltamethrin on adults of each
strain (Table 2) revealed that the Vauclin strain is also highly resistant to deltamethrin
(RR 50 of 56-fold and RR 95 of 76-fold). In both strains, the toxicity of deltamethrin
increased signifi cantly in the presence of detoxifi cation enzyme inhibitors, however
only PBO and DMC induced higher synergistic effects in the Vauclin strain than in the
susceptible Bora-Bora strain (S R50 of 9.94 and 3.76 respectively). In the Vauclin strain,
PBO and DMC signifi cantly reduced the resistance level (from 76-fold to 41-fold and
43-fold respectively for RR 95 ), indicating a signifi cant role of P450s and GSTs in the
resistance of adults to deltamethrin.

Table 2. Insecticidal activity of deltamethrin with and without enzyme inhibitors on adults of Aedes
aegypti Vauclin and Bora-Bora strains.

Strain Enzyme

inhibitor

Body
weight
(mg)

Slope
(± SE)

LD 50
(μg/L)
(95% Cl)

LD 95 (μg/L)
(95% Cl)

RR 50
(95%
Cl)

RR 95
(95% Cl)

SR 50
(95% Cl)

SR 95
(95% Cl)

3.31
(0.27)

18
(16-19)

55
(47-69)

− 2.12 − − − −

3.65
(0.34)

3.4
(3 . 1-3.7)

9.5
(8. 1-12. 1)

5.2
(4.52-5.98)

5.79
(4.30-7.81)

PBO 2.27 − −

Bora-
Bora

2.41
(0.27)

3.4
(3-3.9)

16
(12-25)

5.12
(4.48-5.86)

3.35
(2.42-4.64)

DEF 2.44 − −

2.94
(0.22)

7.3
(6.6-8.1)

27
(22-34)

2.41
(2.11-2.76)

2.09
( 1.57-2. 78)

DMC 2.39 − −

2.61
(0. 19)

990
(880-1100)

4210
(3470-5380)

56
(49-64)

76
(58-99)

− 2.65 − −

9.94
(8. 79-1
1.23)

2.78
(0.17)

99
(91-108)

390
(330-470)

29
(26-33)

41
(31-53)

10.89
(8.64-13. 72)

PBO 2.27

Vauclin

2. 14
(0.22)

170
(150-190)

1000
(750-1510)

49
(43-56)

60
(43-86)

5.81
(5.08-6.65)

4.23
(3.16-5.66)

DEF 2.25

3.68
(2.86-4. 72)
Resistant ratios RR 50 and RR 95 were obtained by calculating the ratio between the LD 50 and LD 95 between Yauclin and
Bora-Bora strains; Synergism ratios SR 50 and SR 95 were obtained by calculating the ratio between LD 50 and LD 95 with and
without enzyme inhibitor. (CI): Confi dence Interval. Signifi cant RR and SR are shown in bold.

2.57
(0. 16)

260
(240-290)

1150
(950-1460)

36
(32-40)

43
(33-57)

3.76
(3.35-4.23)

DMC 2.56