Casimir Dossou Kpanou1,2, Hermann W Sagbohan3,4, Fortuné Dagnon5,6, Germain G Padonou3,4, Razaki Ossè3,7, Albert Sourou Salako3,4, Aboubakar Sidick3, Wilfried Sewadé3, André Sominahouin3,4, Patrick Condo5, Saadani Hassani Ahmed5, Daniel Impoinvil8, Martin Akogbéto3,4. 1. Centre de Recherche entomologique de Cotonou (CREC), Cotonou, Bénin. casimirkpanou@yahoo.com. 2. Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Bénin. casimirkpanou@yahoo.com. 3. Centre de Recherche entomologique de Cotonou (CREC), Cotonou, Bénin. 4. Faculté des Sciences et Techniques de l'Université d'Abomey-Calavi, Abomey-Calavi, Bénin. 5. US President's Malaria Initiative, US Agency for International Development, Cotonou, Bénin. 6. Bill & Melinda Gates Foundation, Lagos, Nigeria. 7. Université Nationale d'Agriculture de Porto-Novo, Porto-Novo, Bénin. 8. US President's Malaria Initiative, Centers for Disease Control and Prevention for Disease Control (CDC), Georgia, USA.
Abstract
BACKGROUND: The selection and the spread of insecticide resistance in malaria vectors to the main classes of insecticides used in vector control tools are a major and ongoing challenge to malaria vector control programmes. This study aimed to determine the intensity of vector resistance to insecticides in three regions of Benin with different agro-ecological characteristics. METHODS: Larvae of Anopheles gambiae sensu lato (s.l.) were collected from September to November 2017 in different larval sites in three northern Benin communes: Parakou, Kandi and Malanville. Two to five-day-old, non-blood-fed, female mosquitoes were exposed to papers impregnated with deltamethrin, permethrin and bendiocarb at dosages of 1 × the diagnostic dose, 5 × and 10 × to determine the intensity of resistance in these vectors. Molecular frequencies of the kdr L1014F and ace-1R G119S insecticide resistance mutations and levels of detoxification enzymes were determined for mosquitoes sampled at each study site. RESULTS: Resistance to pyrethroids (permethrin and deltamethrin) was recorded in all three communes with mortality rates below 60% using the diagnostic dose (1x). The results obtained after exposure of An. gambiae to permethrin 10 × were 99% in Kandi, 98% in Malanville and 99% in Parakou. With deltamethrin 10x, mortality rates were 100% in Kandi, 96% in Malanville and 73% in Parakou. For the diagnostic dose of bendiocarb, suspected resistance was recorded in the communes of Malanville (97%) and Kandi (94%) while sensitivity was observed in Parakou (98%).Using the 10 × dose, mortality was 98% in Kandi, 100% in Malanville and 99% in Parakou. The frequencies of the kdr L1014F allele varied between 59 and 83% depending on the sites and species of the An. gambiae complex, while the frequency of the ace-1R G119S gene varied between 0 and 5%. Biochemical tests showed high levels of oxidase and esterase activity compared to the susceptible colony strain of An. gambiae sensu stricto (Kisumu strain). CONCLUSION: Anopheles gambiae showed a generalized loss of susceptibility to permethrin and deltamethrin but also showed moderate to high intensity of resistance in different regions of Benin. This high intensity of resistance is a potential threat to the effectiveness of vector control.
BACKGROUND: The selection and the spread of insecticide resistance in malaria vectors to the main classes of insecticides used in vector control tools are a major and ongoing challenge to malaria vector control programmes. This study aimed to determine the intensity of vector resistance to insecticides in three regions of Benin with different agro-ecological characteristics. METHODS: Larvae of Anopheles gambiae sensu lato (s.l.) were collected from September to November 2017 in different larval sites in three northern Benin communes: Parakou, Kandi and Malanville. Two to five-day-old, non-blood-fed, female mosquitoes were exposed to papers impregnated with deltamethrin, permethrin and bendiocarb at dosages of 1 × the diagnostic dose, 5 × and 10 × to determine the intensity of resistance in these vectors. Molecular frequencies of the kdr L1014F and ace-1R G119S insecticide resistance mutations and levels of detoxification enzymes were determined for mosquitoes sampled at each study site. RESULTS: Resistance to pyrethroids (permethrin and deltamethrin) was recorded in all three communes with mortality rates below 60% using the diagnostic dose (1x). The results obtained after exposure of An. gambiae to permethrin 10 × were 99% in Kandi, 98% in Malanville and 99% in Parakou. With deltamethrin 10x, mortality rates were 100% in Kandi, 96% in Malanville and 73% in Parakou. For the diagnostic dose of bendiocarb, suspected resistance was recorded in the communes of Malanville (97%) and Kandi (94%) while sensitivity was observed in Parakou (98%).Using the 10 × dose, mortality was 98% in Kandi, 100% in Malanville and 99% in Parakou. The frequencies of the kdr L1014F allele varied between 59 and 83% depending on the sites and species of the An. gambiae complex, while the frequency of the ace-1R G119S gene varied between 0 and 5%. Biochemical tests showed high levels of oxidase and esterase activity compared to the susceptible colony strain of An. gambiae sensu stricto (Kisumu strain). CONCLUSION: Anopheles gambiae showed a generalized loss of susceptibility to permethrin and deltamethrin but also showed moderate to high intensity of resistance in different regions of Benin. This high intensity of resistance is a potential threat to the effectiveness of vector control.
Authors: Albert S Salako; Idelphonse Ahogni; Casimir Kpanou; Arthur Sovi; Roseric Azondekon; André A Sominahouin; Filémon Tokponnon; Virgile Gnanguenon; Fortuné Dagnon; Laurent Iyikirenga; Martin C Akogbeto Journal: Malar J Date: 2018-10-29 Impact factor: 2.979
Authors: Benjamin D Menze; Magellan Tchouakui; Leon M J Mugenzi; Williams Tchapga; Micareme Tchoupo; Murielle J Wondji; Martin Chiumia; Themba Mzilahowa; Charles S Wondji Journal: BMC Infect Dis Date: 2022-07-30 Impact factor: 3.667
Authors: Manfred Accrombessi; Martin C Akogbeto; Edouard Dangbenon; Hilaire Akpovi; Arthur Sovi; Boulais Yovogan; Constantin Adoha; Landry Assongba; Aurore Ogouyemi-Hounto; Germain Gil Padonou; Charles Thickstun; Mark Rowland; Corine Ngufor; Natacha Protopopoff; Jackie Cook Journal: Am J Trop Med Hyg Date: 2022-07-18 Impact factor: 3.707