A Brief History of the Use of Insecticides in Brazil to Control Vector-Borne Diseases, with an Emphasis on the Dengue Vector Aedes aegypti, and Implications for Insecticide Resistance

Background: In Brazil, public health programs have relied predominantly on chemical insecticides to control Aedes aegypti, Anopheles spp., Culex quinquefasciatus, triatomines, and phlebotomines. Rising vector-borne disease (VBD) incidence and mounting insecticide resistance (IR) call for a critical appraisal of historical and current control practices. Methods: We conducted a narrative review of secondary data (1901–2024) from Medline/PubMed and Google Scholar, technical notes, national reports, and ANVISA records. (3) Results: Brazil’s vector control progressed from organochlorines (e.g., DDT) to organophosphates, (1) Background: In Brazil, public health programs have relied predominantly on chemical insecticides to control Aedes aegypti, Anopheles spp., Culex quinquefasciatus, triatomines, and phlebotomines. Rising vector-borne disease (VBD) incidence and mounting insecticide resistance (IR) call for a critical appraisal of historical and current control practices. (2) Methods: We conducted a narrative review of secondary data (1901–2024) from Medline/PubMed and Google Scholar, technical notes, national reports, and ANVISA records. Results: Brazil’s vector control progressed from organochlorines (e.g., DDT) to organophosphates, carbamates, pyrethroids, insect growth regulators, and microbial/spinosyn larvicides, including recent dual-MOA. Ae. aegypti: Widespread resistance to temephos and pyrethroids; decreased susceptibility to pyriproxyfen; no documented Bti resistance; high resistance to pyrethroid; Anopheles spp.: Urban control lacks dedicated national campaigns; effective use of Bti/L. sphaericus with limited resistance reports; resistance likely influenced by collateral exposure from Aedes control and domestic use; Triatomines phlebotomines: Predominant reliance on pyrethroids; most studies indicate susceptibility. Overlapping deployment of organophosphates and pyrethroids across programs likely selected resistance in non-target vectors. Conclusions: Brazil’s century-long, insecticide-centric strategy has delivered episodic gains but fostered Aedes aegypti resistance. Sustainable progress requires strengthened, nationwide IR surveillance and entomological mapping to coordinate cross-program actions.