Metofluthrin Research Articles

Transfluthrin and Metofluthrin as Effective Repellents against Pyrethroid-Susceptible and Pyrethroid-Resistant Aedes aegypti (L.) (Diptera: Culicidae).

Aedes aegypti is a major vector of dengue fever in tropical regions. Spatial repellents (SRs) have shown promise in delaying pesticide resistance. Methods for discriminating concentrations (DCs) are well established using various bioassay tools, while data for high-throughput screening system (HITSS) toxicity bioassay (TOX) are absent. In this study, we compared and optimized lethal (LCs) and sub-lethal concentrations (SLCs) of transfluthrin (TFT) and metofluthrin (MFT) on pyrethroid-susceptible (USDA) and pyrethroid-resistant (Pu-Teuy) Ae. aegypti (L.) strains, using the HITSS-TOX. Mean mortality (MT) was 100% at LC99 and DC, compared to LC50 (45.0 ± 3.7%) and LC75 (65.8 ± 7.0%) for the USDA strain. However, the resistant strain (Pu-Teuy) showed reduced susceptibility against TFT and a significantly lower MT at LC50 (12.5 ± 4.4%; t = 5.665, df = 10, p < 0.001), LC75 (9.2 ± 3.5%; t = 4.844, df = 10, p = 0.001), LC99 (55.0 ± 9.9%; t = 4.538, df = 5, p = 0.006), and DC (75.0 ± 5.2%; U = 3.0, p = 0.007). The DC of TFT (0.15222%) was 4.7-fold higher than for MFT (0.03242%) in USDA strain. The baseline DCs established are useful to better understand susceptibility and the efficacy of various repellents against field populations of Ae. aegypti.

The Penggunaan Insektisida Rumah Tangga dan Kerentanan Aedes sp terhadap Permetrin di Kelurahan Sorosutan Kota Yogyakarta

Abstract. The use of household insecticides is an alternative solution to prevent mosquito bites.Most of the household insecticides sold in Indonesia have pyrethroid active ingredients, permethrin,which is available in the aerosol formulation. Inappropriate use of household insecticides can reducemosquito susceptibility. The objectives of this study are to describe the use of household insecticidesand susceptibility of Aedes sp. against permethrin in Sorosutan Yogyakarta. This study used a crosssectionalsurvey design. This study was conducted in December 2018–April 2019 in 354 householdsin Sorosutan which were randomly selected based on proportional sampling. Interviews about thehousehold insecticides were conducted with the owner or resident of the house. The susceptibilitytests used impregnated paper with permethrin 0.75%. The survey results showed that 25.14% ofthe houses use household insecticides. The insecticide used were aerosol, electric mosquito repellents,and mosquito coils containing active ingredients of the pyrethroid group, namely dimefl uthrin,transfl uthrin, prallethrin, cypermethrin, and metofl uthrin. The susceptibility test results showed adecrease in mosquito susceptibility where the population of Aedes sp. in Sorosutan has been resistantagainst permethrin. The continuous use of insecticides with pyrethroid active ingredients can developmosquito resistance against permethrin because all pyrethroids have the same mode of action. Thisstudy concludes that only a small proportion (25,14%) of the households used insecticides with theactive ingredients used mainly in the pyrethroid group (dimefl uthrin, transfl uthrin, prallethrin,cypermethrin, and metofl uthrin) and the population of Aedes sp. in Sorosutan has been resistant topermethrin.

Comparison of the effects of the synthetic pyrethroid Metofluthrin and phenobarbital on CYP2B form induction and replicative DNA synthesis in cultured rat and human hepatocytes

High doses of Metofluthrin (MTF) have been shown to produce liver tumours in rats by a mode of action (MOA) involving activation of the constitutive androstane receptor leading to liver hypertrophy, induction of cytochrome P450 (CYP) forms and increased cell proliferation. The aim of this study was to compare the effects of MTF with those of the known rodent liver tumour promoter phenobarbital (PB) on the induction CYP2B forms and replicative DNA synthesis in cultured rat and human hepatocytes. Treatment with 50 μM MTF and 50 μM PB for 72 h increased CYP2B1 mRNA levels in male Wistar rat hepatocytes and CYP2B6 mRNA levels in human hepatocytes. Replicative DNA synthesis was determined by incorporation of 5-bromo-2′-deoxyuridine over the last 24 h of a 48 h treatment period. Treatment with 10–1000 μM MTF and 100–500 μM PB resulted in significant increases in replicative DNA synthesis in rat hepatocytes. While replicative DNA synthesis was increased in human hepatocytes treated with 5–50 ng/ml epidermal growth factor or 5–100 ng/ml hepatocyte growth factor, treatment with MTF and PB had no effect. These results demonstrate that while both MTF and PB induce CYP2B forms in both species, MTF and PB only induced replicative DNA synthesis in rat and not in human hepatocytes. These results provide further evidence that the MOA for MTF-induced rat liver tumour formation is similar to that of PB and some other non-genotoxic CYP2B form inducers and that the key event of increased cell proliferation would not occur in human liver.