Insecticide susceptibility of <it>Aedes aegypti </it>and <it>Aedes albopictus </it>in Central Africa

<p>Abstract</p> <p>Background</p> <p><it>Aedes aegypti </it>(Linnaeus, 1762) and <it>Aedes albopictus </it>(Skuse, 1894) are the main vectors of dengue (DENV) and chikungunya (CHIKV) viruses worldwide. As there is still no vaccine or specific treatment for DENV and CHIKV, vector control remains the cornerstone of prevention and outbreak control. Unfortunately, vector control programs are facing operational challenges with mosquitoes becoming resistant to commonly used insecticides in several areas through the world. Throughout Central Africa no recent data are available susceptible/resistant status of either vector species since the introduction/arrival of <it>Ae. albopictus </it>in this area. We therefore studied the level of resistance of these two major vectors to insecticides commonly used in Africa for mosquito control.</p> <p>Results</p> <p><it>Aedes aegypti </it>and <it>Ae. albopictus </it>were sampled in six urban localities of Cameroon (Garoua, Bertoua, Yaoundé, Bafia, Buea) and Gabon (Libreville). Larval bioassays, carried out to determine the lethal concentrations (LC₅₀and LC₉₅) and resistance ratios (RR₅₀and RR₉₅) suggested that both vector species were susceptible to <it>Bti </it>(<it>Bacillus thuringiensis var israeliensis</it>) and temephos. Bioassays were also performed on adults using WHO diagnostic test kits to assess phenotypic resistance to deltamethrin, DDT, fenitrothion and propoxur. These experiments showed that one population of <it>Ae. aegypti </it>(Libreville) and two populations of <it>Ae. albopictus </it>(Buea and Yaoundé) were resistant to DDT (mortality 36% to 71%). Resistance to deltamethrin was also suspected in <it>Ae. albopictus </it>from Yaoundé (83% mortality). All other field mosquito populations were susceptible to deltamethrin, DDT, fenitrothion and propoxur. No increase in the knockdown times (Kdt₅₀and Kdt₉₅) was noted in the Yaoundé resistant population compared to other <it>Ae. albopictus </it>populations, suggesting the possible involvement of metabolic resistance to deltamethrin and DDT.</p> <p>Conclusion</p> <p>In view of the recent increase in dengue and chikungunya outbreaks in Central Africa, these unique comparative data on the insecticide susceptibility of <it>Ae. aegypti </it>and <it>Ae. albopictus </it>could help public health services to design more effective vector control measures.</p>

Abstract licence: CC BY

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46 more references, whose wording the paper’s licence keeps private.

• Aedes Mosquitoes and Aedes-Borne Arboviruses in Africa: Current and Future Threats · 2018

• Corrected

  Contemporary status of insecticide resistance in the major Aedes vectors of arboviruses infecting humans · 2017

• Is Dengue Vector Control Deficient in Effectiveness or Evidence?: Systematic Review and Meta-analysis · 2016

• Insecticide Resistance Status of United States Populations of Aedes albopictus and Mechanisms Involved · 2014

• Bacillus thuringiensis subsp. israelensis and Its Dipteran-Specific Toxins · 2014

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