Evaluation of Long-Lasting Insecticidal Nets (DuraNet ?) Under laboratory and Semi-Field Conditions Using Experimental Huts Against Anopheles Mosquitoes in Jimma Zone, Southwestern Ethiopia

摘要

Background: Long-Lasting Insecticidal Nets (LLINs) efficacy could be compromised due to a lot of influences together with user compliance and vector population insecticide resistance status. Thus, this study was to assess the biological efficacy of DuraNet? with the help of the World Health Organization cone bioassay and field experimental hut. Methods: A laboratory and a semi-field conditions experimental huts against Anopheles Mosquitoes were conducted in southwestern Ethiopia from September 2015 to January 2016. The bio efficacy of DuraNet? was evaluated using the WHO cone bioassay test and then its field efficacy was evaluated using experimental huts against the malaria vector population. Results: World Health Organization cone bioassay tests against pyrethroid-resistant An. arabiensis led to mean percent mortality and knockdown of 78% and 93%, respectively. Washing of DuraNet? successively reduced its efficacy from 93% knockdown (0 wash) to 45% knockdown (20 washes). Similarly, mean mortality decreased from 84% (0 wash) to 47% (20 washes). A total of 1575 female mosquitoes were collected over 40 nights out of which 1373(87.8%) were An. gambiae s.l. , 116 (7.4%) were Anopheles coustani and 107 (6.8%) were An. pharoensis . The mean blood-feeding rate was significantly lower ( P & .001) in hut containing unwashed DuraNet? when compared to hut containing untreated DuraNet?. The mean mortality rate was significantly higher ( P & .001) in hut containing DuraNet? when compared to hut containing untreated DuraNet?. Unwashed DuraNet? showed the highest personal protection 88.7% and 100% against An. Arabiensis and An. pharoensis , respectively. Conclusion: Both DuraNet? and PermaNet 2.0 moderate efficacy against a pyrethroid-resistant population of An. arabiensis from Ethiopia. The bio efficacy of DuraNet? was found below the WHO recommendation. Therefore, the real impact of the observed insecticide resistance against DuraNet? to be further studied under phase-III trials, the need for new alternative vector control tools remains critical.