Compendium of the most significant studies with reference to properties, intake, effects.

Entomology

Richards SL, White AV, Byrd BD, Reiskind MH, Doyle MS. Evaluation of Insecticide Resistance in Aedes albopictus (Diptera: Culicidae) in North Carolina, 2017. J Med Entomol. 2019 Apr 16;56(3):761-773. doi: 10.1093/jme/tjy216.

Abstract. Mosquitoes may develop resistance to insecticide active ingredients (AIs) found in formulated products (FPs) due to environmental exposure from insecticides in mosquito control and/or unrelated to mosquito control, e.g., agricultural, household pest control. Mosquito control programs should implement resistance management strategies by assessing resistance in targeted populations, rotating different classes of insecticides based on resistance testing, and/or increasing insecticide concentration (i.e., saturation, using maximum labeled rate) to overcome emerging resistance. Resistance testing is often done solely on AIs, but should, in some cases, include both AIs and FPs at the concentrations mosquitoes may encounter in the field. The resistance/susceptibility status was determined for adulticides used in mosquito control. ... © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. 

Chen CD, Chin AC, Lau KW, Low VL, Lee HL, Lee PKY, Azidah AA, Sofian-Azirun M. Bioefficacy Evaluation of Commercial Mosquito Coils Containing Metofluthrin, d-Allethrin, d-Trans Allethrin, and Prallethrin Against Aedes albopictus (Diptera: Culicidae) in Malaysia. J Med Entomol. 2018 Oct 25;55(6):1651-1655. doi: 10.1093/jme/tjy130..

Abstract. The bioefficacy of commercial mosquito coils containing four different active ingredients, namely metofluthrin, d-allethrin, d-trans allethrin, and prallethrin against Aedes albopictus (Skuse) (Diptera: Culicidae) from 10 states in Malaysia, was evaluated using the glass chamber method. In this study, Ae. albopictus exhibited various knockdown rates (50% knockdown time, KT50), ranging from 2.50 to 5.00 min, 2.50 to 7.00 min, 3.00 to 8.00 min, and 5.00 to 17.00 min for metofluthrin, d-trans allethrin, d-allethrin, and prallethrin, respectively. Overall, all strains of Ae. albopictus were most susceptible to metofluthrin, with mortality rates >80%. On the other hand, mortality rates ranging from 5.0 to 100% were observed from all populations exposed to d-trans allethrin, d-allethrin, and prallethrin. In addition, significant correlations between KT50 of metofluthrin and d-allethrin (r = 0.758, P = 0.011), metofluthrin and prallethrin (r = 0.676, P = 0.032), d-allethrin and d-trans allethrin (r = 0.832, P = 0.003), d-allethrin and prallethrin (r = 0.921, P = 0.000), and d-trans allethrin with prallethrin (r = 0.941, P = 0.000) were detected, suggesting some levels of cross-resistance within the pyrethroid insecticides. This study demonstrated that metofluthrin can induce high insecticidal activity in Ae. albopictus in Malaysia, followed by d-trans allethrin, d-allethrin, and prallethrin.

Unlu I, Faraji A, Williams GM, Marcombe S, Fonseca DM, Gaugler R. Truck-mounted area-wide applications of larvicides and adulticides for extended suppression of adult Aedes albopictus. Pest Manag Sci. 2019 Apr;75(4):1115-1122. doi: 10.1002/ps.5227.

Abstract. Background: Given the lack of vaccines for most vector-borne diseases, vector control is often the primary option for disease control. Aedes albopictus are difficult to control because the immatures primarily develop in containers ubiquitous in residential properties. Conventional adulticide campaigns often result in brief, rebounding population declines, so incorporating new techniques into an integrated pest management program is imperative. We performed combined area-wide applications of the larvicides Bacillus thuringiensis var. israelensis and pyriproxyfen with the adulticide sumithrin and prallethrin to achieve extended suppression of Ae. albopictus populations in Trenton, NJ, USA. We deployed bioassay cups to assess the spatial penetration and efficacy of the applications.... © 2018 Society of Chemical Industry.

Bibbs CS, Tsikolia M, Bloomquist JR, Bernier UR, Xue RD, Kaufman PE. Vapor toxicity of five volatile pyrethroids against Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles quadrimaculatus (Diptera: Culicidae). Pest Manag Sci. 2018 Dec;74(12):2699-2706. doi: 10.1002/ps.5088. 

Abstract. Background: Mosquito mortality has been documented in numerous studies of spatial repellents but the concentration-dependent toxicity of spatial repellent vapors has not been documented. To address this issue, prallethrin, flumethrin, metofluthrin, transfluthrin, and meperfluthrin were selected for comparative study against Aedes albopictus (Skuse), Ae. aegypti (L.), Culex quinquefasciatus Say, and Anopheles quadrimaculatus Say. Mosquito were exposed to vapors of each chemical for 2, 4, and 24 h with mortality recorded at each time point. A second experiment involved exposing mosquitoes to vapors for 2 h, then transferring them to untreated holding containers and held for 24 h. For these mosquitoes, readings were only taken after 24 h to allow for metabolic detoxification and recovery... © 2018 Society of Chemical Industry.

Safety

Botnariu G, Birsan C, Podoleanu C, Moldovan C, Stolnicu S, Chiriac A. Skin necrosis caused by prallethrin-A worldwide used insecticide. Environ Toxicol Pharmacol. 2016 Apr;43:103-4. doi: 10.1016/j.etap.2016.03.002.

Abstract. We report a case of necrosis caused by the use of prallethrin (mosquito repellent) on the skin in a 67-year-old diabetic female patient suffering from delusions of parasitosis. Cutaneous toxicity due to pyrethroids is less known or reported, despite well-documented pyrethroid poisoning involving the gastrointestinal, respiratory, cardiac, and nervous systems. Skin irritation has been described after acute accidental exposure but, as far as we know, no data have been published on the effects of pyrethroids when applied directly to the skin. Copyright © 2016 Elsevier B.V. 

Senthilkumaran S, Menezes RG, Balamurugan N, Thirumalaikolundusubramanian P. Prallethrin poisoning that taxes the brain. J Anaesthesiol Clin Pharmacol. 2014 Jan;30(1):116-7. doi: 10.4103/0970-9185.125726. 

Abstract. ... As pyrethroids were widely used in our area during the recent dengue epidemic, number of pyrethroid poisoning was reported more compared with last year. Hence, practitioners working in emergency room shall be sensitized on clinical manifestations, course of poisoning, therapeutic modalities and outcome.

Bhaskar EM, Moorthy S, Ganeshwala G, Abraham G. Cardiac conduction disturbance due to prallethrin (pyrethroid) poisoning. J Med Toxicol. 2010 Mar;6(1):27-30. doi: 10.1007/s13181-010-0032-7.

 Abstract. Pyrethroids are common household insecticides. Even though they are less toxic to humans, reports of accidental and suicidal poisoning are not uncommon. Cardiotoxicity due to pyrethroid poisoning is rare. We report a case of cardiac conduction disturbance due to a pyrethroid, prallethrin. A 28-year-old female presented after a suicidal consumption of prallethrin. Her clinical and laboratory parameters were normal during the first 24 h of hospital stay. On the second hospital day, she developed metabolic acidosis and sinus arrest with escape junctional rhythm. Despite correction of metabolic acidosis, the sinus arrest persisted for 3 days. She reverted back to sinus rhythm with bradycardia after this period and was discharged on the seventh hospital day. Her follow-up was uneventful. Pyrethroid poisoning can affect the gastrointestinal, respiratory, and nervous system. Most serious effects of the toxin in humans are seizures and coma. Mechanism of pyrethroid neurotoxicity is believed to be due to its ability to modify sodium, chloride, and calcium channels of the neurons. Our case raises the possibility that cardiac arrhythmia due to pyrethroid poisoning can occur due to its effect on sodium channels in the heart.