TY  - EJOU
AU  - Thiaw, T. Omar
AU  - Bouganali, B. Charles
AU  - Diagne, D. Nafissatou
AU  - Doucouré, D. Souleymane
AU  - Sokhna, S. Cheikh
TI  - Insecticide Resistance in Malaria Vectors in Dielmo and Ndiop: Comparative Analysis of Knock Down Resistance Patterns using Two Sampling Methods in a Malaria Pre-elimination Context
T2  - African Journal of Parasitology, Mycology and Entomology

PY  - 2024
VL  - 2
IS  - 1
SN  - 1987-1473

AB  - Introduction: Vector control is still confronted with the issue of insecticide resistance. This study investigates the impact of this phenomenon on entomological parameters and its distribution according to the mosquito sampling method in Dielmo and Ndiop, two malaria pre-elimination communities. Methods: Mosquitoes were sampled using human landing catch (HLC) and larval collection (LC) methods. Susceptibility tests were performed on LC samples. Larvae were collected using the dipping method from georeferenced breeding sites in the immediate vicinity of the study site. Five pyrethroids (alphacypermethrin, deltamethrin, lambdacyhalothrin, permethrin and etofenprox), one carbamate (bendiocarb) and one organophosphate (fenitrothion) were tested, using 2–5-day-old females. PCR techniques were used to identify Anopheles species and detect the Kdr mutation. Kdr frequencies were calculated under Hardy–Weinberg equilibrium and comparatively analyzed in terms of sampling method, biting behavior, longevity, vector species and study site, using a linear regression model. Results: Mosquitoes were fully susceptible to carbamates and organophosphates. For pyrethroids, mortality rates ranged from 80.3 to 100%. PCR revealed three species, An. coluzzii, An. gambiae and An. arabiensis. The latter predominated at both sites. Kdr frequencies ranged from 2.4 to 14% in Dielmo and from 17.3 to 40% in Ndiop. In Dielmo, An. arabiensis showed a low endophagic rate (36.6%). Biting behavior was independent of Kdr mutation, night period, species and mosquito lifespan but was dependent on the study site (p = 0.008). Comparing the sampling methods, there was a 43% lower chance of finding the kdr mutation in LC females (OR = 0.57; p = 0.03) in Dielmo, against a 3 times higher probability of detecting a Kdr allele in Ndiop (OR = 2.64; p = 0.001). Conclusion: This study underlines the importance of investigating insecticide resistance in host-seeking females, particularly in malaria pre-elimination settings.
KW  - malaria
KW  -  s.l.
KW  - insecticide resistance
KW  - Dielmo
KW  - Ndiop
KW  - pre-elimination
DO  - 10.35995/ajpme02020014