Archive | 2021
Durability of three types of dual active ingredient long-lasting insecticidal net compared to a pyrethroid-only LLIN in Tanzania: protocol for a prospective cohort study nested in a cluster randomized controlled trial
Abstract
Introduction: Progress achieved by long-lasting insecticidal nets (LLINs) against malaria is threatened by the widespread selection of pyrethroid resistance among vector populations. LLINs with non-pyrethroid insecticides are urgently needed. This study aims to assess the durability of three novel dual active ingredient LLINs and to parameterise a mathematical model to predict epidemiological outcomes of these products for malaria vector control. Methods: A WHO Phase 3 active ingredients and textile durability study will be carried out within a cluster randomised controlled trial in Misungwi district in 40 clusters. The following treatments will be evaluated; 1/ Interceptor G2 combining chlorfenapyr and a pyrethroid alpha-cypermethrin, 2/ Royal Guard treated with pyriproxyfen and alpha-cypermethrin and 3/ Olyset Plus which incorporates a synergist piperonyl butoxide and the pyrethroid permethrin, and 4/ a reference standard pyrethroid-only LLIN (Interceptor). 750 nets will be followed in 5 clusters per intervention arm at 6, 12, 24 and 36 months post distribution for survivorship and hole index assessment. A second cohort of 1950 nets per each type will be identified in 10 clusters, of which 30 LLINs will be withdrawn for bio-efficacy and chemical analysis every 6 months up to 36 months and another 30 collected for an experimental hut trial study every year. Bio-efficacy will be assessed using cone bioassays and tunnel tests against susceptible and resistant laboratory strains of Anopheles gambiae sensu stricto. Efficacy of field collected nets will be compared in six experimental huts. The main outcomes will be Anopheles mortality up to 72 hours post exposure, blood feeding and egg maturation using ovary dissection to assess impact on fecundity. Ethics and dissemination: Ethical approval was received from the Tanzanian ethics review committee as well as from each institution. Study findings will be disseminated via reports and presentations to national and international stakeholders, conferences, and peer-reviewed publications.