Abstract
The data indicate a decrease in the efficiency of α-cypermethrin 0.025% (Tkd99 = 21 mn) and of DDT 4% (Tkd99 = 191.5 mn) on An. arabiensis in Analamiranga. Neverthelesss, the effectiveness of permethrin 0.250% has been notified. In Soanierana, α-cypermethrin 0.025% was effective against An. arabiensis, whilst the ineffectiveness of the DDT 4% (Tkd99= 116 mn) in Andranonahoatra was observed. In Alasora, a fall in the effectiveness of α-cypermethrin 0.025% (Tkd99 = 21 mn) and the resistance to DDT 4% (Tkd99 = 6894 mn) was noted. No kdr mutation was detected on the kd gene of An. arabiensis resistant to the α-cypermethrin 0.025% and to DDT 4%, collected in Alasora. An. funestus collected in the district of Miandrivazo is susceptible to pyrethroids and to DDT. To conclude, in the Malagasy Central Highlands, An. arabiensis is ordinary sensitive to pyrethroid and poorly sensitive, or even resistant to DDT (as observed in Antananarivo plain). However, An. funestus remains sensitive to all tested insecticides; this observation is crucial because this anopheles vector is the first target of the campaigns of indoor spraying insecticides.