Insecticide resistance status of Aedes aegypti in southern and northern Ghana
Date
2023
Authors
Journal Title
Journal ISSN
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Publisher
Parasites & Vectors
Abstract
Background Outbreaks of Aedes-borne arboviral diseases are becoming rampant in Africa. In Ghana, there is no
organized arboviral control programme with interventions restricted to mitigate outbreaks. Insecticide application is a
crucial part of outbreak responses and future preventative control measures. Thus, knowledge of the resistance status
and underlying mechanisms of Aedes populations is required to ensure optimal insecticide choices. The present study
assessed the insecticide resistance status of Aedes aegypti populations from southern Ghana (Accra, Tema and Ada
Foah) and northern Ghana (Navrongo) respectively.
Methods Phenotypic resistance was determined with WHO susceptibility tests using Ae. aegypti collected as larvae
and reared into adults. Knockdown resistance (kdr) mutations were detected using allele-specifc PCR. Synergist assays
were performed with piperonyl butoxide (PBO) to investigate the possible involvement of metabolic mechanisms in
resistance phenotypes.
Results Resistance to DDT was moderate to high across sites (11.3 to 75.8%) and, for the pyrethroids deltamethrin
and permethrin, moderate resistance was detected (62.5 to 88.8%). The 1534C kdr and 1016I kdr alleles were common
in all sites (0.65 to 1) and may be on a trajectory toward fxation. In addition, a third kdr mutant, V410L, was detected
at lower frequencies (0.03 to 0.31). Pre-exposure to PBO signifcantly increased the susceptibility of Ae. aegypti to
deltamethrin and permethrin (P<0.001). This indicates that in addition to kdr mutants, metabolic enzymes (monooxy‑
genases) may be involved in the resistance phenotypes observed in the Ae. aegypti populations in these sites.
Conclusion Insecticide resistance underpinned by multiple mechanisms in Ae. aegypti indicates the need for surveil‑
lance to assist in developing appropriate vector control strategies for arboviral disease control in Ghana
Description
Research Article
Keywords
Insecticide resistance, Target-site mutations, Aedes aegypti