Resistance status of Anopheles gambiae s.l. to insecticides following the 2011 mass distribution campaign of long-lasting insecticidal nets (LLINs) in the Plateau Department, south-eastern Benin

• Published in: Malaria Journal
• Main Authors: Arthur Sovi, Renaud Govoétchan, Razaki Ossé, Come Z. Koukpo, Albert S. Salako, Thomas Syme, Rodrigue Anagonou, Augustin Fongnikin, Udoka C. Nwangwu, Frédéric Oké-Agbo, Filémon Tokponnon, Gil Germain Padonou, Martin Codjo Akogbeto
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2020
• Subjects: MIILDs; Efficacy; Resistance; Anopheles gambiae sensu lato; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-020-3116-0; https://doaj.org/article/b259a13f325443358e42b6f725f65134

Abstract Background In 2011, Benin’s National Malaria Control Programme (NMCP) organized a nationwide mass distribution campaign of LLINs throughout the country. Following this intervention, it was important to assess whether the level of susceptibility of malaria vectors to insecticides had remained the same as compared to the pre-intervention period. The current study investigated this. Methods Larval collections were conducted in Ifangni, Sakété, Pobè and Kétou districts located in Plateau department, Southeastern Benin before (2009) and after (2012–2013) LLIN distribution. Anopheles gambiae sensu lato (s.l.) larvae from the 4 study districts were reared to adulthood and WHO susceptibility tests were conducted. The insecticides tested were deltamethrin (0.05%), permethrin (0.75%), bendiocarb (0.1%) and DDT (4%). Molecular species identification as well as, the characterization of the kdr L1014F mutation were also performed in the An. gambiae s.l. complex using PCR method. Results Overall, a significant decrease in mortality rates of An. gambiae s.l. to deltamethrin (0.05%), permethrin (0.75%) and DDT (4%) was observed post-LLIN distribution, respectively: (100% vs 80.9%, p < 0.0001), (77.5% vs 70%, p = 0.01) and, (47.8% vs 4.4%, p < 0.0001). By contrast, susceptibility of vectors to bendiocarb (0.1%) remained the same (100% mortality in the WHO susceptibility tube tests) pre- and post-intervention. An increase in the kdr L1014F frequency was observed post-LLIN distribution [F(kdr) = 0.91)] compared to the pre-intervention period [F(kdr) = 0.56], p < 0.0001. Anopheles coluzzii and An. gambiae were the two molecular species identified in the study area. Conclusion The decrease susceptibility to pyrethroids and DDT as well as, the increase in the frequency of the kdr L1014F mutation after the intervention stressed at the time, the need for the development and implementation of effective insecticide resistance management strategies. At present, an update of the vectors resistance status in the area is ...