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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 esterases in resistance of An. gambiae s.l. to carbamates in Tanguieta district.
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Figure 4: Implication of esterases in resistance of An. gambiae s.l. to carbamates in Tanguieta district.

Mentions: The analysis of Tables 4 and 5 shows that after the addition of synergist DEF in CDC bottles treated with bendiocarb, the LT95 value obtained with Anopheles gambiae Tanguieta populations was 104.76 minutes. This value was lower than the one obtained with bendiocarb alone which was 137.08 minutes. Synergist Ratio (SR) (Before addition of DEF/after addition of DEF) was 1.30. LT50 value before addition of DEF was 5.23 minutes, whereas LT50 value after addition of DEF with the same Anopheles gambiae populations was not determined. The analysis of Figure 4 shows that after the addition of synergist DEF to bendiocarb 12.5 μg/bottle, the percentage of dead mosquitoes from Tanguieta is higher than the one obtained with bendiocarb alone. The use of DEF synergist in CDC bottles treated with bendiocarb 12.5 μg/bottle did not eliminate bendiocarb resistance, but has reduced the level in point of fact that the mortality rate increased from 78.94% to 85.33%. These results suggest an implication of esterases in resistance of Anopheles gambiae s.l.to carbamates.


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 esterases in resistance of An. gambiae s.l. to carbamates in Tanguieta district.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: Implication of esterases in resistance of An. gambiae s.l. to carbamates in Tanguieta district.
Mentions: The analysis of Tables 4 and 5 shows that after the addition of synergist DEF in CDC bottles treated with bendiocarb, the LT95 value obtained with Anopheles gambiae Tanguieta populations was 104.76 minutes. This value was lower than the one obtained with bendiocarb alone which was 137.08 minutes. Synergist Ratio (SR) (Before addition of DEF/after addition of DEF) was 1.30. LT50 value before addition of DEF was 5.23 minutes, whereas LT50 value after addition of DEF with the same Anopheles gambiae populations was not determined. The analysis of Figure 4 shows that after the addition of synergist DEF to bendiocarb 12.5 μg/bottle, the percentage of dead mosquitoes from Tanguieta is higher than the one obtained with bendiocarb alone. The use of DEF synergist in CDC bottles treated with bendiocarb 12.5 μg/bottle did not eliminate bendiocarb resistance, but has reduced the level in point of fact that the mortality rate increased from 78.94% to 85.33%. These results suggest an implication of esterases in resistance of Anopheles gambiae s.l.to carbamates.

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