Publications scientifiques
Edmond Kopya
Autres affiliations : Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale
Leslie Nkahe
Autres affiliations : Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale
Roland Bamou
Autres affiliations : Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale
Timoléon Tchuinkam
Benjamin D. Menze
Autres affiliations : Ministry of Scientific Research and Innovation
Charles S. Wondji
Autres affiliations : Ministry of Scientific Research and Innovation
Christophe Antonio‐Nkondjio
Autres affiliations : Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale
Parfait Awono‐Ambene
Parasite
In Cameroon, pyrethroid-only long-lasting insecticidal nets (LLINs) are still largely used for malaria control. The present study assessed the efficacy of such LLINs against a multiple-resistant population of the major malaria vector, Anopheles coluzzii, in the city of Yaoundé via a cone bioassay and release-recapture experimental hut trial. Susceptibility of field mosquitoes in Yaoundé to pyrethroids, DDT, carbamates and organophosphate insecticides was investigated using World Health Organization (WHO) bioassay tube tests. Mechanisms of insecticide resistance were characterised molecularly. Efficacy of unwashed PermaNet ® 2.0 was evaluated against untreated control nets using a resistant colonised strain of An. coluzzii . Mortality, exophily and blood feeding inhibition were estimated. Field collected An. coluzzii displayed high resistance with mortality rates of 3.5% for propoxur (0.1%), 4.16% for DDT (4%), 26.9% for permethrin (0.75%), 50.8% for deltamethrin (0.05%), and 80% for bendiocarb (0.1%). High frequency of the 1014F west-Africa kdr allele was recorded in addition to the overexpression of several detoxification genes, such as Cyp6P3, Cyp6M2, Cyp9K1, Cyp6P4 Cyp6Z1 and GSTe2 . A low mortality rate (23.2%) and high blood feeding inhibition rate (65%) were observed when resistant An. coluzzii were exposed to unwashed PermaNet ® 2.0 net compared to control untreated net ( p < 0.001). Furthermore, low personal protection (52.4%) was observed with the resistant strain, indicating reduction of efficacy. The study highlights the loss of efficacy of pyrethroid-only nets against mosquitoes exhibiting high insecticide resistance and suggests a switch to new generation bed nets to improve control of malaria vector populations in Yaoundé.
