ISCEP 2026 At Sunway Putra Hotel 17-18 August 2026
ABSTRACT
POSTER PRESENTATION ABSTRACT
P20
EVALUATING THE RESIDUAL EFFICACY AND STRAIN- DEPENDENT PERSISTENCE OF BIFENTHRIN SURFACE TREATMENTS AGAINST AEDES AEGYPTI
Fatin Nur Adlina ROZAIDI, Norlaili MISRAWI, Aimi Afiqah MOHAMMADIN, Ezita Qaisara RIDZUAN, Mohammad Farizul MOHAMMAD FATIHI, Haziq Uzair MOHD ROSLI, Afiq Asyraf MOHD FAIZOL, Farah Diana ARIFFIN, Nurulhusna AB HAMID
Medical Entomology Unit Infectious Disease Research Centre, Institute for Medical Research Nati of Health Ministry of Heal Selangor Malaysia
The operational effectiveness of residual insecticide applications against Aedes aegypti, the primary vector of dengue, is strongly determined by the concentration of the active ingredient retained within treated surfaces. This study aims to evaluate the effectiveness of a water-based suspension concentrate formulation of 10% w/v bilanthrin at two operational concentrations, C, (0.09%/active ingredient 1:200 dilution ratio) and C, 1010% w/v active ingredient: 1100 dilution ratio, comparing a laboratory strain (LS) and a field-collected wild strain (WS) under semi-held conditions using standard WHO cone bioassays. Adult female masquitoes were exposed to treated surfaces across three vertical resting heights (40 cm, 80 cm, and 120 cm), with 24-hour post-exposure mortality monitored over a 56-day evaluation cycle. Preliminary results demonstrate that efficacy depends heavily on concentration and the specific mosquito strain. At C, the laboratory strain exhibited high initial efficacy (85.00 ± 11.23% at Day 7; peak 6.67 ± 5.77% at Day 28] before dropping sharply to 10.97 80-40% by Day 56. Escalating the concentration to C, significantly extended residual longevity (7708± 15.71% at Day 56). In contrast, the wild strain at C, exhibited a low initial response (4.44 770% at Day 7) before rising to 63.77 ± 14.51% at Day 56. Doubling the concentration to C, succmfully overcame this slow start in the wild strain raising Day 7 mortality to 61.25 13.02%, despite cyclical dips at Day 14 (23.08 ± 1.36%) and Day 42 (25.77 ± 1.63%). Efficacy trends were generally comparable across all evaluated vertical resting heights. These findings demonstrate that evaluating only laboratory strains tends to overestimate initial field performance against wild populations. Optimising bentin application concentrations is critical to overcoming early response lags and securing sustainable vector suppression within broader dengue control programmes
Keywords: benthin, Aedes aegypt, cone bioassay, residual efficacy insecticide concentration, dengue vector management
INTERNATIONAL SCIENTIFIC CONFERENCE ON ENTOMOLOGY AND PEST SCEP) 2006