Elimite
Personal protection afforded by controlled-release topical repellents and permethrin-treated clothing against natural populations of Aedes taeniorhynchus.

Schreck CE, Kline DL.

U.S. Department of Agriculture, Insects Affecting Man and Animals Research Laboratory, Gainesville, FL 32604.

Field tests evaluated repellent formulations containing deet in combination with permethrin-impregnated or untreated military uniforms against Aedes taeniorhynchus. No significant difference was determined between repellents in duration of protection whether or not permethrin-treated clothing was worn, but there were differences in efficacy relative to site of application. The head was the site of shorter duration of protection regardless of repellent tested. On repellent-treated skin, 12-30% of the bites were on arms, whereas 70-88% were on the head. When military repellent was used, the head was bitten 35% more often than with experimental repellents. On untreated clothing 80% of bites were through pants and 20% through shirts. Mean bites through untreated clothing were 0.7 bites/min/person (42/hr), whereas mean bites through permethrin-impregnated clothing were 0.0004/min/person (0.02/hr). Protection by permethrin-treated clothing relative to untreated clothing was 99.9%.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2708993&dopt=Abstract permethrin Elimite



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Neurobehavioral effects of permethrin are associated with alterations in regional levels of biogenic amine metabolites and amino acid neurotransmitters.

Hudson PM, Tilson HA, Chen PH, Hong JS.

Oral administration of 120 or 240 mg/kg permethrin produced dose- and time-related tremor in rats with the peak effect occurring 5 hrs after dosing. Subsequent experiments done 5 hrs postdosing found that 45 to 180 mg/kg permethrin produced dose-related increases in rectal temperature and enhanced responsiveness to an acoustic stimulus. Tremor was detected at 90 and 180 mg/kg. Neurochemical analyses of regional biogenic amines and their metabolites and amino acids 5 hrs after 90 or 180 mg/kg indicated that 5-HIAA levels were increased in the hypothalamus (HYP), brain stem (BS), hippocampus (HPC), and striatum (STR); 5-HT was not affected. MHPG was increased in the HYP and BS, while NE was decreased at the high dose only. DOPAC and HVA were increased in the STR after 90 and 180 mg/kg, while DA was not affected. Aspartate levels were increased in the BS and STR; glutamate was increased in the BS. Taurine, glutamine, glycine, and GABA were not affected. A time-course analysis of neurochemical changes 2, 5, 12, and 24 hrs postdosing indicated that 5 hrs was the time of peak effect for permethrin. Permethrin-induced tremor and hyperthermia were significantly correlated with dose- and time-related changes in MHPG, 5-HIAA, and ASP.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2872638&dopt=Abstract permethrin Elimite



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Microsomal enzyme induction by permethrin in rats.

Anadon A, Diez MJ, Sierra M, Sanchez JA, Teran MT.

Departamento de Toxicologia, Facultad de Veterinaria, Universidad de Leon, Spain.

The synthetic pyrethroid, permethrin, was evaluated for its ability to alter hepatic microsomal drug-metabolizing function. The influence of permethrin (25:75 cis-trans) on plasma antipyrine kinetics and gamma-glutamyl transpeptidase (gamma-GTP) activity were studied in rats. After 3 days of administration of 90 mg permethrin/kg/day, there was no significant change in the antipyrine half-life and the area under the curve, while the apparent volume of distribution and clearance were significantly increased. Treatment with 190 mg permethrin/kg/day for 3 days decreased antipyrine half-life and the area under the curve, and increased the apparent volume of distribution and the clearance significantly. The gamma-GTP activity was significantly increased within 21 days and 14 days after the start of permethrin administration, at doses of 90 and 190 mg permethrin/kg/day, respectively. The antipyrine kinetics results indicate that permethrin is capable of producing a dose-dependent marked enzyme-inducing effect.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2902710&dopt=Abstract permethrin Elimite



Elimite
Effectiveness of controlled-release personal-use arthropod repellents and permethrin-impregnated clothing in the field.

Gupta RK, Sweeney AW, Rutledge LC, Cooper RD, Frances SP, Westrom DR.

Letterman Army Institute of Research, Presidio of San Francisco, CA 94129.

Two topical controlled-release personal-use arthropod repellent formulations of diethyl methylbenzamide (deet) and permethrin-impregnated clothing were tested on human volunteers in a tropical rain forest near Innisfail, Queensland, Australia. The field trials were arranged in a four-way factorial design which compared fabric types, permethrin treatment and repellent treatments over a 14-hour test period. An analysis of variance with each factor treated as a fixed effect indicated that treatment of the clothing with permethrin and use of topical repellents were effective in preventing bites. The controlled release formulations were not significantly better than the current U.S. Army formulation of deet under field conditions. The repellent formulations and the permethrin-treated clothing used as one system provided better protection than the repellent formulations or permethrin-treated clothing used separately.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2904965&dopt=Abstract permethrin Elimite



Elimite
The influence of permethrin-impregnated bednets and mass drug administration on the incidence of Plasmodium falciparum malaria in children in Sabah, Malaysia.

Hii JL, Vun YS, Chin KF, Chua R, Tambakau S, Binisol ES, Fernandez E, Singh N, Chan MK.

Department of Medical Services, Kota Kinabalu, Sabah, Malaysia.

A small-scale trial was carried out in the Upper Kinabatangan district of Sabah, Malaysia, to determine the effect of using permethrin-impregnated bednets on malaria transmission. A total of 306 nylon bednets with cotton borders, impregnated at a dose estimated to have been 0.062 g permethrin/m2 of nylon netting, were distributed to 139 households in five villages. At the time of distributing bednets, mass drug administration with Fansidar plus primaquine was also administered to the human population to clear all parasitaemias due to Plasmodium falciparum Welch. In another village, for comparison, mass drug administration was the only intervention. After intervention measures in December 1984 and January 1985, the parasite rates in children declined in all villages during the first month, significantly more in the villages with impregnated bednets than in the control, thus proving that the nets had an impact on malaria. However, after about 2 months, parasite rates started to increase again. After 4-6 months, parasite rates in the villages with bednets approached the rate in the control village without nets. The increase in parasite rates was paralleled by a significant deterioration in the quality, physical condition and the degree of non-utilization of bednets. Entomological evaluation proved the efficacy of permethrin-impregnated nets for controlling Anopheles balabacensis Baisas and other anophelines. Bioassays (1 h exposure) of permethrin-impregnated bednets gave 100% mortality initially and 44-61% mortality after 85-106 days. Mosquito collections in treated bednets were significantly reduced for at least 217 days. The project failed to achieve prolonged suppression of malaria transmission for a combination of entomological, sociological and practical reasons which are discussed in relation to the objectives and implementation of future bednet studies.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2979556&dopt=Abstract permethrin Elimite