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PubMed2003

Efficacy of permethrin-impregnated uniforms in the prevention of cutaneous leishmaniasis in Iranian soldiers.

BACKGROUND: One approach for prevention of cutaneous leishmaniasis (CL) is the creation of a barrier between the insect vector (phlebotoms) and the host. Many but not all researchers claim that permethrin-impregnated uniforms are effective for prevention of CL. We determined the efficacy of permethrin-impregnated uniforms for prevention of CL in Iranian soldiers. METHODS: A total of 324 soldiers were randomized to two equal groups, of which 272 soldiers completed the study. In group A, 134 soldiers were issued permethrin-impregnated uniforms. In group B, 138 soldiers were issued uniforms washed in water. The soldiers wore uniforms day and night for 3 months, and were observed for an additional period of 6 months. All the soldiers remained in the leishmania-endemic area of Isfahan during the 3 months. RESULTS: Nine (6.5%) of 138 soldiers wearing control uniforms and six (4.4%) of 134 soldiers wearing permathrin-impregnated uniforms acquired CL. The difference between two groups was not statistically significant (P < 0.05). CONCLUSION: Permethrin-impregnated uniforms are not effective for the prevention of CL.

Adult↗

PubMed2000

Permethrin resistance ratios compared by two methods of testing nymphs of the German cockroach, Blattella germanica.

For the German cockroach, Blattella germanica L. (Dictyoptera: Blattellidae), the permethrin resistance ratio (RR) was assessed by topical application and by tarsal contact tests, using first-instar nymphs of five strains from Tehran, Iran. Each test was replicated three or four times with 10 nymphs aged 2-3 days; mortality was scored 24h post-treatment. The reference susceptible strain showed LD50 permethrin 0.0175 microl/nymph from topical application, KT50 of 8.41 min and LT50 of 12.82 following tarsal contact with permethrin 15 mg/m2. In four wild strains (F1 generation) the RR varied from 4.14 to 4.7 for mortality after topical application, from 4.2 to 6.45 for mortality and 17-27 for knockdown following tarsal contact tests. Hence, overall knockdown results gave much higher RRs than for mortality data. Resistance ratios based on both methods of treatment were very similar: one strain showed a slightly higher value by topical application (RR 4.6 vs. 4.2, i.e. 1.1-fold difference) whereas the other three strains gave slightly greater RR (1.2-1.4 fold) by tarsal contact. Resistance was abolished by cotreatment with the synergist piperonyl butoxide plus permethrin (ratio 3:1 required for full efficacy), indicating that mixed-function oxidases were inhibited as a major metabolic pathway in all four resistant strains.

Animals↗

PubMed2003

Synergism between permethrin and propoxur against Culex quinquefasciatus mosquito larvae.

To see if synergism occurs between carbamate and pyrethroid insecticides, we tested permethrin and propoxur as representatives of these two classes of compounds used for mosquito control. Larvicidal activity of both insecticides was assessed separately and together on a susceptible strain of the mosquito Culex quinquefasciatus (Diptera: Culicidae) by two methods. When mixed at a constant ratio (permethrin : propoxur 1 : 60 based on LC50) and tested at serial concentrations to plot dose/mortality regression, significant synergy occurred between them (co-toxicity coefficient = 2.2), not just an additive effect. For example, when the mixture gave 50% mortality, the same concentrations of permethrin and propoxur alone would have given merely 2 x 1% mortality. When a sublethal dose (LC0) of permethrin or propoxur was added to the other (range LC10-LC95), synergism occurred up to the LC80 level. Synergistic effects were attributed to the complementary modes of action by these two insecticide classes acting on different components of nerve impulse transmission. Apart from raising new possibilities for Culex control, it seems appropriate to consider using such mixtures or combinations for insecticide-treated mosquito nets in situations with insecticide-resistant Anopheles malaria vectors.

Animals↗

PubMed2004

Solid-phase microextraction (SPME) of permethrin residues from cucumber using a silica-bonded phase-coated stainless steel fibre.

Solid-phase microextraction (SPME) is a rapid, economic and solvent-free sample preparation method for the isolation of an analyte from its matrix. The technique uses a few centimetres of some adsorptive materials such as activated charcoal, polydimethylsiloxane or octadecyl silane coated onto fused silica optical fibres or, more recently, stainless steel fibres mounted into a microsyringe. The proposed method allows the extraction of permethrin from cucumber matrix into the coating, avoiding sample handling and saving evaporation of solvents and concentration steps. Adsorbed permethrin was desorbed in the split/splitless injection port of the gas chromatograph. The time required for each run was about 1.5 h, which gave a preconcentration of several orders of magnitude. The method could separate and quantify cis- and trans-isomers of permethrin. The calibration curve showed linearity in the range 1-9 micrograms ml-1, with detection limits of 0.03 and 0.05 microgram ml-1 for the cis- and trans-isomers of permethrin, respectively. The method had a recovery rate of about 70% and a relative standard deviation of less than 13%. Results suggest that this procedure provides a rapid and sensitive alternative method to those currently available.

Adsorption↗

PubMed2001

Combined exposure to DEET (N,N-diethyl-m-toluamide) and permethrin-induced release of rat brain mitochondrial cytochrome c.

The release of cytochrome c from the mitochondrial intermembrane space can induce apoptosis. The levels of mitochondrial cytochrome c in rat brain following a single dermal dose of 400 mg/kg of DEET, and of 1.3 mg/kg of permethrin, alone or in combination were determined. Rats were sacrificed at a time interval of 0.5, 1, 2, 4, 8, 16, 24, 48, or 72 h after dosing. Brain mitochondria were isolated and the levels of cytochrome c were measured using reversed-phase high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection. Average percentage recovery of cytochrome c spiked with control rat brain mitochondria was 83.2 +/- 8.9%. Limits of detection and quantitation were 1 and 5 ng, respectively. The results showed that a single dermal dose of a combination of DEET and permethrin significantly increased the release of brain mitochondrial cytochrome c starting 24 h after treatment. DEET and permethrin alone did not affect the release of cytochrome c. The results indicate that combined exposure to DEET and permethrin might induce the apoptotic processes in rat brain as seen by the release of cytochrome c.

Animals↗

PubMed2001

DEET (N,N-diethyl-m-toluamide) alone and in combination with permethrin increased urinary excretion of 6beta-hydroxycortisol in rats, a marker of hepatic CYP3A induction.

In this study, the ratio of 6beta-hydroxycortisol (6beta-OHF) to free cortisol (F) was determined in urine following a single dermal dose of 400 mg/kg of DEET (N,N-diethyl-m-toluamide), and 1.3 mg/kg of permethrin, alone and in combination, in rats. Urine samples were collected at 2, 4, 8, 16, 24, 48, and 72 h after application. Recoveries of 6beta-OHF and cortisol (F) from control urine samples were between 75 and 85%, with limits of detection at 30 and 10 ng/ml for cortisol and 6beta-OHF, respectively. A single dermal dose of DEET alone and in combination with permethrin significantly increased urinary excretion of 6beta-hydroxycortisol 24 h after dosing. Permethrin did not significantly alter the urinary excretion of 6beta-hydroxycortisol. These results indicate that DEET, alone and in combination with permethrin, increased urinary excretion of 6beta-OHF in rats following a single dermal dose application.

Animals↗

PubMed2002

Acute ingestion poisoning with insecticide formulations containing the pyrethroid permethrin, xylene, and surfactant: a review of 48 cases.

BACKGROUND: Forty-eight patients poisoned with insecticide formulations containing permethrin (a Type I pyrethroid insecticide), xylene, and surfactants are reported here. These patients were diagnosed and treated in the Chang Gung Memorial Hospital in Taiwan from January 1987 to June 1999. Ten patients ingested permethrin in error and 38 patients attempted suicide. Gastrointestinal tract signs and symptoms were most common (35/48; 73%), and included sore throat, mouth ulcerations, dysphagia, epigastric pain, and vomiting. Pulmonary abnormalities were documented in 29% (14/48) of patients. Aspiration pneumonitis occurred in eight patients, including onefatal case. Pulmonary edema was observed in two patients. Sixteen patients (33%) had central nervous system involvement including confusion (6/48; 13%), coma (10/48; 21%), and seizures (4/48; 8%). Cardiovascular symptoms in 3/48 (7%) patients were limited to arrhythmias and shock. Mild renal and hepatic dysfunction was found in 5/48 (10%) and 3/48 (6%) of patients, respectively. Leukocytosis occurred in 16 patients (33%) but was not associated with infection. Only one death occurred during this 12.5-year period. CONCLUSION: Poisoning caused by ingesting insecticides containing permethrin, xylene, and surfactant manifests primarily gastrointestinal tract symptoms and signs. The involvement of the central nervous system and lungs were less common, but clinically more significant. The relative contributions of the 20% permethrin, 70% xylene, and 10% surfactant to these toxic manifestations, however, is uncharacterized.

Adult↗

PubMed2003

Dissipation and mobility of permethrin in the field with repeated applications under tropical conditions.

Studies on persistence, mobility and the effect of repeated application of permethrin on its half-life were carried out under field conditions. The half-life of permethrin in the top 20 cm of the soil increased from 11.5 to 23.6 days as the application rates increased from 35 to 140 g ha(-1). Induced by heavier rainfall, more residues moved downward in trial 2 than in trial 1. Repeated applications enhanced degradation rates and mobility of permethrin in the soil. The residue level in the 0-5-cm layer was reduced at day 28 after 17 consecutive applications to a level lower than after 5 applications. The half-life of permethrin was reduced from 15.9 days to 11.2 days after 5 and 17 applications, respectively. The residue reached the 15-20 cm layer much earlier (approximately 3 days after treatment) in soil that received 17 applications as compared to those with two applications.

Chromatography, High Pressure Liquid↗

PubMed1990

Permethrin metabolism in pyrethroid-resistant adults of the horn fly (Muscidae: Diptera).

The in vivo metabolism of topically applied 14C-permethrin was determined for adults of pyrethroid-resistant and -susceptible horn flies, Haematobia irritans (L.) at 1, 2, and 6 h after treatment. At 1 and 2 h after treatment, resistant horn flies had significantly higher internal levels of radioactivity (permethrin plus metabolites) compared with adults of the susceptible strain. Analysis of the internal extracts by thin-layer chromatography indicated no differences in the levels of permethrin. However, significantly higher levels of metabolites that co-chromatograph with 3-(2'- or 4'-hydroxyphenoxy)benzyl (1RS) cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate at 1 and 2 h after treatment and (1RS) cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid at 1 h after treatment. These results demonstrate that an enhanced penetration and metabolism are present during the early phases of permethrin intoxication. Enhanced metabolism may contribute to the ability of resistant horn flies to survive in the presence of pyrethroids.

Animals↗

PubMed1990

Resistance of permethrin to weathering in fabrics treated for protection against mosquitoes (Diptera: Culicidae).

Two different methods of treating cotton and nylon-cotton fabrics with permethrin were evaluated for protection from mosquito bites after laboratory weathering. Cotton fabric treated by the individual dynamic absorption method provided consistently better protection than cotton fabric treated by the aerosol method. The nylon-cotton fabric provided similar protection regardless of the treatment method. After weathering, the toxic effects of both types of permethrin-treated fabrics treated by both methods diminished much more rapidly than did the repellent effect. Low residual amounts of permethrin in the fabrics provided 85% protection from bites against Aedes aegypti (L.) and 93% protection against Anopheles stephensi Liston. Permethrin-treated fabrics were effective in providing protection from mosquito bites for long periods, even after exposure to weathering, and appear to be an effective means of reducing nuisance effects and disease transmission by mosquitoes.

Analysis of Variance↗

PubMed1990

Comparative field evaluation of permethrin and deet-treated military uniforms for personal protection against ticks (Acari).

The effectiveness of permethrin-impregnated (PI) versus permethrin-sprayed (PS) military battle dress uniforms was evaluated in protecting soldiers from tick bite. At the same time, an extended-duration formulation of N,N-diethyl-m-toluamide (deet), when applied to clothing only, was evaluated and compared with the permethrin-treated uniforms. Testing consisted of exposing subjects, clothed in either untreated or the variously treated uniforms, to field populations of ticks during a series of 30-min field trials over a period of 21 d during July and August 1988. Permethrin, applied as either a spray (0.5% [AI]), or as an impregnant (0.125% [AI]/cm2), was more effective than deet (33.25% [AI]) applied to clothing only in protecting individuals from tick bite. The mean numbers of ticks on deet-treated, PI, and PS uniforms were 60, 97, and 98% lower, respectively, than on untreated uniforms against all encountered life stages of Amblyomma americanum (L), Dermacentor variabilis (Say), and Ixodes dammini Spielman, Clifford, Piesman and Corwin.

Animals↗

PubMed1992

Laboratory and field trials of permethrin-treated cotton used as nesting material to control fleas (Insecta: Siphonaptera) on cricetid rodents.

Upholstery cotton treated with four different concentrations (0.25-2.0%) (2,500-20,000 ppm) of an aqueous permethrin solution, used as nesting material by white mice, was laboratory-tested against the potential plague vectors Oropsylla montana (Baker), Thrassis bacchi (Rothschild), and Orchopeas howardi (Baker) and found highly effective (P less than 0.001) for 1 yr. Similarly treated cotton gauze was tested under ambient and 75% RH and was found to be highly effective (P less than 0.001) in both environments for 1 yr. A separate test determined that the LD50 of permethrin-treated cotton was less than 10 ppm. Cotton tested with 0.5% permethrin and distributed under field conditions to cricetid rodents for use as nesting material was found to be highly effective (P less than 0.001 as a pulicide for greater than 4 mo when tested during winter in Larimer County, Colo. Permethrin-treated cotton was less successful in controlling fleas on cricetid rodents during the summer months in a New Mexico hyperendemic plague area.

Animals↗

PubMed1996

Evaluation of permethrin-impregnated cotton balls as potential nesting material to control ectoparasites of woodrats in California.

The dusky-footed woodrat, Neotoma fuscipes Baird is a natural reservoir of the Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, in California. To investigate the potential of host-targeted insecticide to control the tick vectors of B. burgdorferi, permethrin-impregnated or untreated cotton balls were distributed in metal cylinders as potential nesting material adjacent to 95 woodrat houses in chaparral-covered rangeland. Laboratory experiments demonstrated that adult woodrats would enter the cylinders and construct nests from permethrin-treated or untreated cotton. The residual concentration of permethrin did not vary significantly during an 11-mo period and remained > 60% of the registered insecticidal formulation (7.5% [AI] by cotton weight). The abundance of 4 species of ticks (Ixodes neotomae Cooley; the western blacklegged tick I. pacificus Cooley & Kohls; I. woodi Bishopp; and the Pacific Coast tick, Dermacentor occidentalis Marx) infesting woodrats was similar in the treatment and control areas. Although > 90% of the cotton disappeared from the metal cylinders in both areas, examination of 8 active woodrat houses revealed that small amounts of cotton had been incorporated into the nest cups of only 25%. In contrast, the abundance of the flea Orchopeas sexdentatus (Baker) decreased significantly in the treatment area only. Spirochetes were not detected in 168 adult O. sexdentatus fleas that had fed on spirochetemic woodrats, which demonstrates that this flea is an inefficient host of B. burgdorferi. We conclude that the use of permethrin-impregnated cotton as potential nesting material is ineffective for controlling ticks associated with the dusky-footed woodrat in brushlands, but this methodology may be useful for reducing populations of sylvatic fleas.

Animals↗

PubMed2000

Effects of permethrin on the salivary glands and neuroendocrine organs of unfed female Hyalomma (Hyalomma) dromedarii (Ixodoidea: Ixodidae).

Permethrin-impregnated fabric has been shown to be an effective repellent against various tick species. However, some tick species are not repelled by this chemical. In Hyalomma dromedarii (Koch), permethrin exposure is reported to actually enhance the tick's attachment behavior. This study evaluated the histological effects of permethrin exposure on the salivary glands and neuroendocrine organs of unfed, virgin H. dromedarii ticks of uniform age. Three fabric treatments consisting of unwashed-untreated (control), washed after treatment (0.125 mg [AI] / cm2) and unwashed-treated were used after 5- and 10-min exposure times for unfed, unmated females. For all of the organs examined, the cellular structure of treated ticks differed from controls as evidenced by increases in cellular activity, as well as significant increases in the size of the cells of the organs under study (P < 0.05). These data conclusively demonstrate that an unexpected enhanced attachment response observed in this tick species after permethrin exposure is the direct result of increased neurosecretory and salivary gland activity induced by that exposure.

Animal Feed↗

PubMed1988

Observations on the susceptibility of Ctenocephalides felis (Siphonaptera: Pulicidae) to malathion and permethrin in Tanzania.

Laboratory-reared Ctenocephalides felis (Bouche) adults were tested with 0.5% malathion and 0.5% permethrin, using the standard WHO methods. After 24 h exposure to malathion (3.6 mg/cm2), 92% of the fleas died. The LT50 for malathion was approximately 8 h. Permethrin (0.45 mg/cm2) produced 100% mortality of exposed insects after 24 h while with a higher dose (0.9 mg/cm2) all fleas died after 8 h exposure. LT50 for the two doses of permethrin were 7.7 and 1.05 h, respectively. The failure of the diagnostic dose of malathion to kill 100% of the population was attributed to resistance. Permethrin is a suitable pesticide for controlling fleas of domestic animals in Tanzania.

Animals↗

PubMed1991

Residual activity of microencapsulated permethrin against stable flies on lactating dairy cows.

Emulsifiable concentrate and microencapsulated formulations of permethrin were evaluated for residual activity against stable flies on lactating dairy cows. Cows were treated in the field with each formulation and hair was clipped from the leg and shoulder area, and bioassayed at 1, 2, 3, 4, 7 and 14 days after treatment. Significantly more stable flies died when exposed to hair sampled 3, 4 and 7 days after treatment from the shoulder than from the lower leg. Analysis with gas chromatography of hair samples showed no detectable permethrin residues on shoulder or leg hair 72 h after treatment with the emulsifiable concentrate formulation. Microencapsulated permethrin was still detectable on hair sampled from both locations 7 days after treatment. The permethrin concentration on the leg hair was approximately 50% of the shoulder hair concentration after 3 days, with the leg hair residue dropping to 31% of shoulder level after 7 days.

Animals↗

PubMed1986

Permethrin 1% creme rinse for the treatment of Pediculus humanus var capitis infestation.

Permethrin 1% creme rinse (NIX) was tested as a treatment for Pediculus humanus var capitis (head lice) in a placebo-controlled, double-blinded, randomized study. As a positive control, a third arm of the study included nonrandomized, but investigator-blinded, treatment with 1% lindane shampoo (Kwell). At 14 days after treatment, 97% of patients treated with permethrin were free of lice compared to 6% of placebo-treated patients (P less than 0.001) and 43% of the lindane-treated group. Permethrin was 70% ovicidal compared to 14% for placebo (P less than 0.001) and 45% for lindane. No adverse experiences were noted during this study. Permethrin 1% demonstrated high pediculicidal and ovicidal activities, which in combination with its low mammalian toxicity, residual activity, and cosmetic properties, make it an excellent treatment for pediculosis capitis.

Adolescent↗

PubMed1980

Field trials to assess the efficacy of permethrin for the control of flies on cattle.

Permethrin [3-phenoxybenzyl (+/-) cis, trans--2,2dimethyl-3-(2,2-dichlorovinyl) cyclopropane-1-carboxylate], a new synthetic pyrethroid, was applied to cattle on farms in the United Kingdom to assess its efficacy in fly control under field conditions. When 250 ml 0.1 per cent permethrin was applied to the backs of cattle using a knapsack sprayer, adequate control of horn flies, Haematobia irritans, was achieved for over three weeks. Application of 500 ml 0.1 per cent all over each animal gave one to two weeks' control of stable flies, Stomoxys calcitrans, and satisfactory control of non-biting flies for one week. Application of permethrin through a spray arch, using approximately one litre 0.05 per cent permethrin for each animal, gave similar control.

Administration, Topical↗