Evidence supporting deployment of next generation insecticide treated nets in Burkina Faso: bioassays with either chlorfenapyr or piperonyl butoxide increase mortality of pyrethroid-resistant Anopheles gambiae

Malaria Journal

Ellen Dotson¹  Taiwo S. Awolola²  Aristide S. Hien³  Dramane Coulibaly³  Dieudonné D. Soma³  Samina Maiga³  Abdoulaye Diabaté³  Roch K. Dabiré³  Adama Koné⁴  Djenam Jacob⁵  Richard M. Oxborough⁵  Allison Belemvire⁶  Mame B. Diouf⁷ 

[1] Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 30333, Atlanta, GA, USA;Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, 30333, Atlanta, GA, USA;Centers for Disease Control and Prevention, U.S. President’s Malaria Initiative, Atlanta, GA, USA;Institut de Recherche en Sciences de La Santé (IRSS), Bobo-Dioulasso, Burkina Faso;PMI VectorLink Burkina Faso, Abt Associates Inc, Ouagadougou, Burkina Faso;PMI VectorLink Project, Abt Associates Inc, 6130 Executive Blvd, 20852, Rockville, MD, USA;U.S. President’s Malaria Initiative, U.S. Agency for International Development, Washington, DC, USA;U.S. President’s Malaria Initiative, US Embassy Ouagadougou, Ouagadougou, Burkina Faso;

关键词: Pyrethroid;    Insecticide resistance;    Piperonyl butoxide;    Chlorfenapyr;    Anopheles gambiae;    Insecticide-treated net;    Malaria;    Burkina Faso;   

DOI  :  10.1186/s12936-021-03936-3

来源: Springer

【 摘 要 】

BackgroundPyrethroid resistance poses a major threat to the efficacy of insecticide-treated nets (ITNs) in Burkina Faso and throughout sub-Saharan Africa, particularly where resistance is present at high intensity. For such areas, there are alternative ITNs available, including the synergist piperonyl butoxide (PBO)-based ITNs and dual active ingredient ITNs such as Interceptor G2 (treated with chlorfenapyr and alpha-cypermethrin). Before deploying alternative ITNs on a large scale it is crucial to characterize the resistance profiles of primary malaria vector species for evidence-based decision making.MethodsLarvae from the predominant vector, Anopheles gambiae sensu lato (s.l.) were collected from 15 sites located throughout Burkina Faso and reared to adults for bioassays to assess insecticide resistance status. Resistance intensity assays were conducted using WHO tube tests to determine the level of resistance to pyrethroids commonly used on ITNs at 1×, 5 × and 10 × times the diagnostic dose. WHO tube tests were also used for PBO synergist bioassays with deltamethrin and permethrin. Bottle bioassays were conducted to determine susceptibility to chlorfenapyr at a dose of 100 µg/bottle.ResultsWHO tube tests revealed high intensity resistance in An. gambiae s.l. to deltamethrin and alpha-cypermethrin in all sites tested. Resistance intensity to permethrin was either moderate or high in 13 sites. PBO pre-exposure followed by deltamethrin restored full susceptibility in one site and partially restored susceptibility in all but one of the remaining sites (often reaching mortality greater than 80%). PBO pre-exposure followed by permethrin partially restored susceptibility in 12 sites. There was no significant increase in permethrin mortality after PBO pre-exposure in Kampti, Karangasso-Vigué or Mangodara; while in Seguenega, Orodara and Bobo-Dioulasso there was a significant increase in mortality, but rates remained below 50%. Susceptibility to chlorfenapyr was confirmed in 14 sites.ConclusionHigh pyrethroid resistance intensity in An. gambiae s.l. is widespread across Burkina Faso and may be a predictor of reduced pyrethroid ITN effectiveness. PBO + deltamethrin ITNs would likely provide greater control than pyrethroid nets. However, since susceptibility in bioassays was not restored in most sites following pre-exposure to PBO, Interceptor G2 may be a better long-term solution as susceptibility was recorded to chlorfenapyr in nearly all sites. This study provides evidence supporting the introduction of both Interceptor G2 nets and PBO nets, which were distributed in Burkina Faso in 2019 as part of a mass campaign.

【 授权许可】

CC BY