Thème :

Surveillance épidémiologique et prévention des maladies infectieuse

Type de présentation :

Présentation Orale

Titre abstract :

Insusceptibility of An. gambiae populations to insecticides in the city of Yaoundé Cameroon

Auteurs :

Nadège SONHAFOUO CHIANA^1,2

 

Institutions:

¹Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon; ²Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon

Corresponding authors :

nadou_chiana33@yahoo.fr

Référence :

CaHReF 2018, Yaoundé Congres hall, 08 – 11 January 2019 , OSEP039

Abstract :

Background: Insecticide resistance has emerged as one of the major challenges affecting malaria vector control in Africa. The present study presents data on the susceptibility status of An. gambiae population to insecticide in the city of Yaoundé.

Objectif: Assess the level of resistance in mosquitoes to improve mosquitoes control in the city of Yaoundé Cameroon

Methodolody: Batches of 3-5 days old adult female mosquitoes reared from larval collections between 2017 and 2018 in 32 districts of the city of Yaoundé were exposed to deltamethrin (0.05%),; bendiocarb (0.1%) and DDT (4%) according to WHO guidelines. To also assess the level of resistance, field An. Gambiae population and a susceptible reference laboratory strain An. gambiae Kisumu were exposed to deltamethrin, for a range of exposure times and assessed deaths 24 hours later. Control, dead and survivors mosquitoes from WHO susceptibility test; and only survivors and general population from CDC bottle bioassay were characterized for the target-site mutations (kdr).

Results: High insecticide resistance levels were recorded for deltamethrin (5.33 to 24.67%) and DDT (0 to 6.67%). The mortality rate after exposing mosquitoes to bendiocarb, varied from 84 to 100%. We found an unexpectedly strong resistance phenotype to deltamethrin with CDC bottle bioassay in An. Gambiae populations. Almost all mosquitoes tested had the West Kdr allele L1014F and this resistance allele was found at high frequency. Molecular analysis suggested the presence of both An. gambiae and An. coluzzii in the different districts.

Conclusion/Recommandation: The study shows rapid evolution of insecticide resistance in vectors population of the city of Yaoundé and suggests the need for an integrated vector control approach to improve control mosquitoes in this city.

Key Words: Vector control, Mosquitoes, Insecticide resistance, Cameroon