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Mixed-function oxidases and esterases associated with permethrin, deltamethrin and bendiocarb resistance in Anopheles gambiae s.l. in the south-north transect Benin, West Africa.

Aïzoun N, Aïkpon R, Padonou GG, Oussou O, Oké-Agbo F, Gnanguenon V, Ossè R, Akogbéto M - Parasit Vectors (2013)

Bottom Line: The susceptibility of Anopheles gambiae Agbalilame and Kandi populations to permethrin and deltamethrin respectively, increased significantly when synergized by PBO, suggesting an implication of mono-oxygenases in resistance of Anopheles gambiae s.l. to pyrethroid.Esterases may play a role in bendiocarb resistance in Anopheles gambiae Tanguieta.Synergists partially restored susceptibility to pyrethroid and carbamate insecticides and might help mitigate the impact of vector resistance in Anopheles gambiae Agbalilame, Kandi and Tanguieta populations.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Insecticide resistance monitoring is essential to help national programmers to implement more effective and sustainable malaria control strategies in endemic countries. The current study aimed at an exploring the involvement of detoxifying enzymes in the insecticide phenotype resistance in Anopheles gambiae s.l.from Benin, in order to guide future malaria vector control interventions.

Methods: Larvae and pupae of Anopheles gambiae s.l. mosquitoes were collected from the breeding sites in Oueme, Atacora and Alibori provinces. CDC susceptibility tests were conducted on unfed female mosquitoes aged 2-5 days old. CDC bioassays were performed with stock solutions of permethrin (21.5 μg per bottle), deltamethrin (12.5 μg per bottle) and bendiocarb (12.5 μg per bottle). CDC biochemical assays using synergists were also conducted to assess the metabolic resistance.

Results: The susceptibility of Anopheles gambiae Agbalilame and Kandi populations to permethrin and deltamethrin respectively, increased significantly when synergized by PBO, suggesting an implication of mono-oxygenases in resistance of Anopheles gambiae s.l. to pyrethroid. Esterases may play a role in bendiocarb resistance in Anopheles gambiae Tanguieta.

Conclusion: Synergists partially restored susceptibility to pyrethroid and carbamate insecticides and might help mitigate the impact of vector resistance in Anopheles gambiae Agbalilame, Kandi and Tanguieta populations. However, additional vector control tools are needed to further impact on malaria transmission in such settings.This will improve the implementation and management of future control programs against this important malaria vector in Benin and in Africa in general.

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Implication of mono-oxygenases in resistance of An. gambiae s.l. to pyrethroid in Kandi district.
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Figure 5: Implication of mono-oxygenases in resistance of An. gambiae s.l. to pyrethroid in Kandi district.

Mentions: The analysis of Table 6 and Table 7 shows that after the addition of synergist PBO to CDC bottles treated with deltamethrin, the KdT50 value obtained with Anopheles gambiae Kandi populations was 7.79 minutes. This value was lower than the one obtained with deltamethrin alone, which was 43.11 minutes. A similar pattern was observed with KdT95 values obtained with these same populations, which was 51.82 minutes after the addition of synergist PBO. This value was also lower than the one obtained with deltamethrin alone which was 108.37 minutes. Synergist Ratio (SR) (Before addition of PBO/ after addition of PBO) was 5.53 for KdT50, whereas Synergist Ratio (SR) (Before addition of PBO/after addition of PBO) of these same populations was 2.09 for KdT95. The analysis of Figure 5 shows that after the addition of synergist PBO to deltamethrin 12.5 μg/bottle, the percentage of dead mosquitoes from Kandi was higher than the one obtained with deltamethrin alone. The use of PBO synergist in CDC bottles treated with deltamethrin 12.5 μg/bottle did not eliminate deltamethrin resistance, but has significantly reduced the level in point of fact that the mortality rate increased from 43.13% to 88.67%. These results also suggest an implication of mono-oxygenases in the resistance of Anopheles gambiae s.l. to pyrethroids.


Mixed-function oxidases and esterases associated with permethrin, deltamethrin and bendiocarb resistance in Anopheles gambiae s.l. in the south-north transect Benin, West Africa.

Aïzoun N, Aïkpon R, Padonou GG, Oussou O, Oké-Agbo F, Gnanguenon V, Ossè R, Akogbéto M - Parasit Vectors (2013)

Implication of mono-oxygenases in resistance of An. gambiae s.l. to pyrethroid in Kandi district.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750545&req=5

Figure 5: Implication of mono-oxygenases in resistance of An. gambiae s.l. to pyrethroid in Kandi district.
Mentions: The analysis of Table 6 and Table 7 shows that after the addition of synergist PBO to CDC bottles treated with deltamethrin, the KdT50 value obtained with Anopheles gambiae Kandi populations was 7.79 minutes. This value was lower than the one obtained with deltamethrin alone, which was 43.11 minutes. A similar pattern was observed with KdT95 values obtained with these same populations, which was 51.82 minutes after the addition of synergist PBO. This value was also lower than the one obtained with deltamethrin alone which was 108.37 minutes. Synergist Ratio (SR) (Before addition of PBO/ after addition of PBO) was 5.53 for KdT50, whereas Synergist Ratio (SR) (Before addition of PBO/after addition of PBO) of these same populations was 2.09 for KdT95. The analysis of Figure 5 shows that after the addition of synergist PBO to deltamethrin 12.5 μg/bottle, the percentage of dead mosquitoes from Kandi was higher than the one obtained with deltamethrin alone. The use of PBO synergist in CDC bottles treated with deltamethrin 12.5 μg/bottle did not eliminate deltamethrin resistance, but has significantly reduced the level in point of fact that the mortality rate increased from 43.13% to 88.67%. These results also suggest an implication of mono-oxygenases in the resistance of Anopheles gambiae s.l. to pyrethroids.

Bottom Line: The susceptibility of Anopheles gambiae Agbalilame and Kandi populations to permethrin and deltamethrin respectively, increased significantly when synergized by PBO, suggesting an implication of mono-oxygenases in resistance of Anopheles gambiae s.l. to pyrethroid.Esterases may play a role in bendiocarb resistance in Anopheles gambiae Tanguieta.Synergists partially restored susceptibility to pyrethroid and carbamate insecticides and might help mitigate the impact of vector resistance in Anopheles gambiae Agbalilame, Kandi and Tanguieta populations.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Insecticide resistance monitoring is essential to help national programmers to implement more effective and sustainable malaria control strategies in endemic countries. The current study aimed at an exploring the involvement of detoxifying enzymes in the insecticide phenotype resistance in Anopheles gambiae s.l.from Benin, in order to guide future malaria vector control interventions.

Methods: Larvae and pupae of Anopheles gambiae s.l. mosquitoes were collected from the breeding sites in Oueme, Atacora and Alibori provinces. CDC susceptibility tests were conducted on unfed female mosquitoes aged 2-5 days old. CDC bioassays were performed with stock solutions of permethrin (21.5 μg per bottle), deltamethrin (12.5 μg per bottle) and bendiocarb (12.5 μg per bottle). CDC biochemical assays using synergists were also conducted to assess the metabolic resistance.

Results: The susceptibility of Anopheles gambiae Agbalilame and Kandi populations to permethrin and deltamethrin respectively, increased significantly when synergized by PBO, suggesting an implication of mono-oxygenases in resistance of Anopheles gambiae s.l. to pyrethroid. Esterases may play a role in bendiocarb resistance in Anopheles gambiae Tanguieta.

Conclusion: Synergists partially restored susceptibility to pyrethroid and carbamate insecticides and might help mitigate the impact of vector resistance in Anopheles gambiae Agbalilame, Kandi and Tanguieta populations. However, additional vector control tools are needed to further impact on malaria transmission in such settings.This will improve the implementation and management of future control programs against this important malaria vector in Benin and in Africa in general.

Show MeSH
Related in: MedlinePlus