Countrywide insecticide resistance monitoring and first report of the presence of the L1014S knock down resistance in Niger, West Africa

• Published in: Malaria Journal
• Main Authors: Hadiza Soumaila, Boubé Hamani, Ibrahim Issa Arzika, Amadou Soumana, Abdoulaye Daouda, Fatoumata Abdoulaye Daouda, Souleymane Mahaman Iro, Samira Gouro, Maman Sani Zaman-Allah, Izamné Mahamadou, Saadou Kadri, Noura Maman Salé, Wilfried Hounkanrin, Boubacar Mahamadou, Halima Naroua Zamaka, Rabiou Labbo, Ibrahim Maman Laminou, Hadiza Jackou, Sabiti Idrissa, Eric Coulibaly, Zilahatou Bahari-Tohon, Els Mathieu, Jenny Carlson, Ellen Dotson, Taiwo Samson Awolola, Cecilia Flatley, Joseph Chabi
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2022
• Subjects: Insecticide resistance; Resistance mechanisms; New generation ITNs; Malaria; Niger; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic; Keita
• Online Access: https://doi.org/10.1186/s12936-022-04410-4; https://doaj.org/article/cc2cccadba664d108c39c66bb1f52d02

Abstract Background Mass distribution of insecticide-treated nets (ITNs) is the principal malaria vector control strategy adopted by Niger. To better inform on the most appropriate ITN to distribute, the National Malaria Control Programme (NMCP) of Niger and its partners, conducted insecticide resistance monitoring in selected sites across the country. Methods The susceptibility of Anopheles gambiae sensu lato (s.l.) to chlorfenapyr and pyrethroid insecticides was investigated in a total of sixteen sites in 2019 and 2020, using 2–5-day-old adults reared from wild collected larvae per site. The susceptibility status, pyrethroid resistance intensity at 5 and 10 times the diagnostic concentrations, and piperonyl butoxide (PBO) synergism with diagnostic concentrations of deltamethrin, permethrin and alpha-cypermethrin were assessed using WHO bioassays. Two doses (100 and 200 µg/bottle) of chlorfenapyr were tested using the CDC bottle assay method. Species composition and allele frequencies for knock-down resistance (kdr-L1014F and L1014S) and acetylcholinesterase (ace-1 G119S) mutations were further characterized using polymerase chain reaction (PCR). Results High resistance intensity to all pyrethroids tested was observed in all sites except for alpha-cypermethrin in Gaya and Tessaoua and permethrin in Gaya in 2019 recording moderate resistance intensity. Similarly, Balleyara, Keita and Tillabery yielded moderate resistance intensity for alpha-cypermethrin and deltamethrin, and Niamey V low resistance intensity against deltamethrin and permethrin in 2020. Pre-exposure to PBO substantially increased susceptibility with average increases in mortality between 0 and 70% for tested pyrethroids. Susceptibility to chlorfenapyr (100 µg/bottle) was recorded in all sites except in Tessaoua and Magaria where susceptibility was recorded at the dose of 200 µg/bottle. Anopheles coluzzii was the predominant malaria vector species in most of the sites followed by An. gambiae sensu stricto (s.s.) and Anopheles arabiensis. The ...