Studies of malaria-vector mosquitoes in KwaZulu-Natal Province, South Africa found susceptibility to 4% DDT (WHO's susceptibility standard), in 63% of the samples, compared to the average of 87% in the same species caught in the open. The authors concluded that "Finding DDT resistance in the vector "An. arabiensis", close to the area where we previously reported pyrethroid-resistance in the vector "An. funestus" Giles, indicates an urgent need to develop a strategy of insecticide resistance management for the malaria control programmes of southern Africa."