A village level cluster-randomized entomological evaluation of combination long-lasting insecticidal nets containing pyrethroid plus PBO synergist in Southern Mali

Malaria Journal

Research

Dereje Dengela¹  Richard M. Oxborough¹  Kristen George²  Christen Fornadel²  Laura Norris²  Jules Mihigo³  Aboubacar Sadou³  Abdourhamane Dicko⁴  Moussa B. M. Cisse⁵  Djibril Sangare⁶ 

[1] PMI Africa Indoor Residual Spraying Project, Abt Associates 4550 Montgomery Ave, Suite 800 North, 20814, Bethesda, MD, USA;President’s Malaria Initiative USAID, 1300 Pennsylvania Avenue NW, Washington, DC, USA;President’s Malaria Initiative USAID, BP 34, ACI2000; Rue 243, Porte 297, Bamako, Mali;Programme National de Lutte Contre le Paludisme (PNLP), Ministère de la Santé, Bamako, Mali;Université des Sciences Techniques et Technologiques de Bamako (USTTB), Bamako, Mali;Université des Sciences Techniques et Technologiques de Bamako (USTTB), Bamako, Mali;Malaria Research and Training Center (MRTC), University of Bamako, Bamako, Mali;

关键词: LLIN;    PBO;    MFOs;    Combination nets;    Anopheles gambiae;    Pyrethroid resistance;    Mali;    Permanet 3.0;    Olyset Plus;   

DOI  :  10.1186/s12936-017-2124-1

 received in 2017-07-18, accepted in 2017-11-15,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundThere is growing concern that malaria vector resistance to pyrethroid insecticides may reduce the effectiveness of long-lasting insecticidal nets (LLINs). Combination LLINs are designed to control susceptible and pyrethroid-resistant mosquito populations through a mixture of pyrethroid with piperonyl butoxide (PBO) synergist. A cluster randomized trial with entomology outcome measures was conducted in Mali to determine the added benefit over mono-treated pyrethroid predecessors. Four LLIN treatments; permethrin + PBO, permethrin, deltamethrin + PBO, and deltamethrin, were randomly allocated to four villages each (16 villages total) and distributed to cover every sleeping place. Entomological monitoring of indoor Anopheles resting densities, host preference, vector longevity, and sporozoite rates were monitored every 2 months over 2 years in 2014 and 2015.ResultsBottle bioassays confirmed permethrin and deltamethrin resistance in Anopheles gambiae sensu lato (s.l.), (the predominant species throughout the study) with pre-exposure to PBO indicating partial involvement of oxidases. Between 2014 and 2015 the mean indoor resting density was greater in the deltamethrin + PBO LLIN arm than the deltamethrin LLIN arm at 3.05 (95% CI 3.00–3.10) An. gambiae s.l. per room per day compared with 1.9 (95% CI 1.87–1.97). There was no significant difference in sporozoite rate at 3.97% (95% CI 2.91–5.02) for the deltamethrin LLIN arm and 3.04% (95% CI 2.21–3.87) for deltamethrin + PBO LLIN arm (P = 0.17). However, when analysed by season there was some evidence that the sporozoite rate was lower in the deltamethrin + PBO LLIN arm than deltamethrin LLIN arm during the rainy/high malaria transmission seasons at 1.95% (95% CI 1.18–2.72) and 3.70% (95% CI 2.56–4.84) respectively (P = 0.01).ConclusionsWhile there was some evidence that An. gambiae s.l. sporozoite rates were lower in villages with deltamethrin + PBO LLINs during the high malaria transmission seasons of 2014–2015, there was no reduction in parity rates or indoor resting densities. There was also no evidence that permethrin + PBO LLINs provided any improved control when compared with permethrin LLINs. Combination nets may have a greater impact in areas where mixed function oxidases play a more important role in pyrethroid resistance.

【 授权许可】

CC BY   
© The Author(s) 2017