Deltamethrin Microencapsulation in Emulsion Paint Binder and Its Long-Term Efficacy Against Dengue Vector Aedes aegypti

Abstract

Various control interventions have been effective in the control of arthropod vectors to a certain extent; still, sustained vector control is an existing problem globally. Insecticide-based formulations have been found to be useful, however the proper delivery of active molecules to target vectors is important. Currently, synthetic pyrethroid deltamethrin (DM) has been microencapsulated in the emulsion paint binder and evaluated for long-term effectiveness against dengue vector Aedes aegypti. Different compositions of emulsion binder were prepared by varying the content of monomer and DM. A selection was made for the composition yielding the best combination of properties like solid content, intrinsic viscosity, and DM content. Developed formulation was tested against laboratory-reared and pathogen-free Ae. aegypti mosquitoes. Encapsulation of DM in emulsion binder during polymerization showed a uniform distribution. The optimized formulation was stable and did not have a considerable plasticizing effect. Scanning electron microscopy revealed that grain-like micro crystals of DM and surfactant sodium lauryl sulfate (SDS) were uniformly distributed on the formulation surface. The best optimized formulation was highly effective against dengue vector Ae. aegypti and found to provide efficacy for up to 18 months of application. The knockdown time (KDT) values KDT10 and KDT50 were 7.4 min (95% CI: 5.6–9.1) and 22.1 min (95% CI: 19.7–24.3) respectively, whereas 24 h corrected mortality was 90% (95% CI: 82.5–97.5) after 18 months of application (T18). The probit model used to determine knockdown values did not deviate from the linearity and displayed normal distribution of knockdown % with time for different formulations (p ≥ 0.1). Presently developed DM microencapsulated emulsion binder was stable, smooth, and uniform. The binder displayed excellent anti-insect property and was capable of providing long-term effectiveness against dengue vectors Ae. aegypti. Such a formulation after field-scale evaluation could be very useful in attaining long-term protection from arthropod vectors.

Deltamethrin Contact Exposure Mediated Toxicity and Histopathological Aberrations in Tissue Systems of Public Health Importance Cockroach Species Periplaneta americana and Blattella germanica

“…In an earlier study it was observed that cytoplasmic vacuolization was associated with deltamethrin-mediated initial changes, which resulted in autophagy and apoptosis ( Gutiérrez et al, 2016 ). The toxic effect of deltamethrin may not necessarily be due to direct toxicity ( Gondhalekar et al, 2013 ; Acharya et al, 2021 ) but deltamethrin exposure may result in excito-repellency ( Dhiman et al, 2021 ), homeostasis imbalance in the midgut thereby reducing the ability to digest food for nutrients ( Huang et al, 2015 ), dysregulation of the breathing activities ( Unkiewicz-Winiarczyk and Gromysz -K, 2012 ) and also limiting in the production of signaling molecules that regulate its own physiology ( Caccia et al, 2019 ). Deltamethrin was detected on the body surface of cockroach but not found in brain, ovary and gut tissue using HPLC.…”

Comparative Efficacy of Pyrethroid-Based Paints against Turkestan Cockroaches

“…Micro-encapsulation of active ingredients in a polymeric matrix is another development of a controlled released delivery system of insecticides reported to have residual efficacy against cockroaches and some crawling insects [ 12 , 20 ]. The novel advancement of paint formulation by imbedding microencapsulated insecticide into latex paint offers a prolonged residual effect as compared to earlier insecticide paint (IP) products [ 21 , 22 ]. In these paints, the AIs slowly migrate to the substrate surface as the paint dries, meaning the insecticide is usable for a prolonged time.…”

Measured efficacy, bioaccumulation, and leaching of a transfluthrin‐based insecticidal paint: a case study with a nuisance, nonbiting aquatic insect

“…Semi‐volatile pyrethroids are among the active ingredients used in formulated insecticidal paint products, combining the benefits of insect repellency and mortality 3,4 . Field‐realistic investigations have demonstrated product efficacy in indoor and outdoor settings against targeted insect populations 5–7 . Labelled as a ‘ready‐to‐use’ product, paint formulations can contain single or multiple active ingredients from different insecticide classes, including organophosphates, carbamates, insect growth regulators, and pyrethroids 8…”

“…3,4 Field-realistic investigations have demonstrated product efficacy in indoor and outdoor settings against targeted insect populations. [5][6][7] Labelled as a 'ready-to-use' product, paint formulations can contain single or multiple active ingredients from different insecticide classes, including organophosphates, carbamates, insect growth regulators, and pyrethroids. 8 Transfluthrin (CAS: 118712-89-3; TFL) is a 4th generation, polyfluorobenzyl pyrethroid, which was first synthesized in 1976 as a 'hygiene knock-down insecticide.'…”