Insecticide resistance intensity and efficacy of synergists with pyrethroids in Anopheles gambiae (Diptera: Culicidae) from Southern Togo

• Published in: Malaria Journal
• Main Authors: Yawo Apetogbo, Koffi M. Ahadji-Dabla, Dieudonné Diloma Soma, Adjovi D. Amoudji, Edoh Koffi, Kossivi I. Akagankou, Rabila Bamogo, Kelly Lionelle Ngaffo, Samina Maiga, Rachid T. Atcha‑Oubou, Ameyo M. Dorkenoo, Lucrecia Vizcaino, Audrey Lenhart, Abdoulaye Diabaté, Roch Kounbobr Dabiré, Guillaume Koffivi Ketoh
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2022
• Subjects: Malaria; Anopheles gambiae; Vector control; Intensity resistance; Togo; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-022-04377-2; https://doaj.org/article/26d672a8c3d648018d12b6e373e36b58

Abstract Background This study was designed to provide insecticide resistance data for decision-making in terms of resistance management plans in Togo. Methods The susceptibility status of Anopheles gambiae sensu lato (s.l.) to insecticides used in public health was assessed using the WHO tube test protocol. Pyrethroid resistance intensity bioassays were performed following the CDC bottle test protocol. The activity of detoxification enzymes was tested using the synergists piperonyl butoxide, S.S.S-tributlyphosphorotrithioate and ethacrinic acid. Species-specific identification of An. gambiae s.l. and kdr mutation genotyping were performed using PCR techniques. Results Local populations of An. gambiae s.l. showed full susceptibility to pirimiphos methyl at Lomé, Kovié, Anié, and Kpèlè Toutou. At Baguida, mortality was 90%, indicating possible resistance to pirimiphos methyl. Resistance was recorded to DDT, bendiocarb, and propoxur at all sites. A high intensity of pyrethroid resistance was recorded and the detoxification enzymes contributing to resistance were oxidases, esterases, and glutathione-s-transferases based on the synergist tests. Anopheles gambiae sensu stricto (s.s.) and Anopheles coluzzii were the main species identified. High kdr L1014F and low kdr L1014S allele frequencies were detected at all localities. Conclusion This study suggests the need to reinforce current insecticide-based malaria control interventions (IRS and LLINs) with complementary tools.