All of the following factors are responsible for resurgence of malaria, except:
Mosquito nets are a personal protection measure from mosquito bites during sleep. They are not responsible for resurgence of malaria. Ref: Preventive and Social Medicine, by K.Park, 19th edition, Page 210, 219, 346, 628; Harrison's Principles of Internal Medicine, 16th edition, Page 1221.
Drug Resistance in Parasite
Insecticide Resistance in vectors
Antigenic mutations in parasite
Use of bed nets