What question did this study set out to answer?

The study aims to investigate the factors contributing to high insecticide resistance among Anopheles gambiae populations in Ghana.

June 13, 2026Open Access

High resistance of Anopheles gambiae s.L. populations to public health insecticides in Ghana: contribution of domestic and agricultural pesticide use

Key Points

The study aims to investigate the factors contributing to high insecticide resistance among Anopheles gambiae populations in Ghana.
Anopheles larvae were collected from eight sites and reared to adults.
WHO insecticide susceptibility assays were performed on female Anopheles gambiae s.l. to assess resistance.
Surveys evaluated household insecticide use and agricultural pesticide application.
Coastal zone populations showed 50-85.9% mortality for pyrethroids at 10x exposure.
Sahel zone populations had >98% mortality for pyrethroids at 10x exposure.
High prevalence of L1014F mutation was noted at all sites, suggesting a genetic basis for resistance.

Abstract

Malaria elimination efforts in sub-Saharan Africa are increasingly threatened by the spread of insecticide resistance in Anopheles gambiae sensu lacto (s.l.). The widespread use of insecticides in vector control and pesticides in agriculture has intensified resistance development in malaria vectors. This study examined the drivers of high insecticide resistance in Anopheles mosquitoes in Ghana’s Coastal and Sahel Savannah ecological zones. Anopheles larvae were collected from eight sites across the Coastal Savannah (Tuba, Opeibea, Nima, and Teshie) and Sahel Savannah (Kpalsogu, Libga, Taha, and Kulaa) zones and reared to adults. WHO insecticide susceptibility intensity assays were performed on 3–5-day-old female Anopheles gambiae s.l. to assess phenotypic resistance. The polymerase chain reaction (PCR) technique was used to identify species within the An. gambiae s.l. and detect mutations at voltage-gated sodium channels (Vgsc- 1014F , Vgsc- 1014S , Vgsc- 1575Y ) and acetylcholinesterase G119S-Ace - 1 mutation. Alongside larval sampling, a survey was conducted to assess household use of insecticide-based vector control products and pesticide application in agriculture. Anopheles gambiae s.l. from the Coastal zone showed high resistance intensity to pyrethroids (Mortality rate: 50 to 85.9% at 10x). In the Sahel zone, moderate resistance intensity (Mortality rate: >98% at 10x) was observed. High resistance intensity to pirimiphos-methyl (80–90% at 10x) was recorded in vectors from Tuba and Opeibea. The prevalence of L1014F - kdr mutation was high (range: 0.81 to 1) in all study sites, while L1014S and N1575Y kdr mutations were present at low to moderate frequencies (range: 0 to 0.39). Household surveys revealed widespread use of pyrethroid-based mosquito control products (88.10%), including aerosol sprays (25.33%) and coils (53.95%). Farm surveys showed extensive application of pesticides containing organophosphates (16.2%), carbamates (11.29%), neonicotinoids (25.7%), and diamides (5.4%). This study reveals widespread pyrethroid and organophosphate resistance in Anopheles gambiae s.l,. which could likely be associated with intensive insecticide use in public health and agriculture. With resistance escalating, continuous surveillance and enhanced resistance management strategies are essential to sustain malaria control efforts in Ghana. Not applicable.

Mark Helpful

Bookmark

Relay

View Full Paper