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PubMed2003

Comparative toxicity of permethrin- and bifenthrin-treated cloth fabric for Anopheles farauti and Aedes aegypti.

In this laboratory study, we applied 3 formulations of permethrin (Peregin 500 EC, Dragnet 500 EC, and Dragnet 100 ME) and 2 of bifenthrin (Biflex 10 ME and Talstar 80 SC) to swatches of Australian military shirt fabric. The knockdown and mortality of Anopheles farauti and Aedes aegypti after exposure to treated fabrics were compared. The mortality of An. farauti exposed to permethrin-treated swatches for 3 min in World Health Organization test kits was 94.2-100% after initial treatment and fell to < 28% after 2 cold water washes. and knockdown was < 20% after 3 washes. The mortality of An. farauti exposed to bifenthrin-treated swatches was initially 100% and remained > 55% after 3 washes, whereas knockdown was < 25% after 2 washes. Mortality of Ae. aegypti exposed by tarsal contact to permethrin- and bifenthrin-treated fabrics was 84.8-100% prior to washing and fell to < 21% and < 40%, respectively, after 1 cold water wash. The ability of Ae. aegypti to obtain a blood meal through treated fabrics was variable, and a small percentage (0-6.1%) of mosquitoes obtained a blood meal through fabrics after initial treatment. The effect of cold water washing on the persistence of both chemicals in fabric by chemical assays showed that between 58% and 66% of both chemicals was lost from the test fabric after a single wash.

Aedes↗

PubMed2004

[Study on measuring host-guest ratio of inclusion compound of beta-CD-permethrin by IR].

Permethrin is one of the agrochemicals used in tea gardens currently with the characteristic of being easily decomposed in light. Permethrin with beta-cyclodextrin(CD) made into Inclusion Compound (IC) can increase its stability and reduce dosage to remain on the tea. Host/guest ratio is one of the important parameters of IC. The IC of permethrin with beta-CD was prepared by means of liquid phase method and characterized by using IR. The result of the IR proves that the characteristic absorption peaks of the host and guest are not changed by forming their IC. The host/guest ratio of the IC measured by IR is 1:1. Potassium sulfocyanate (KSCN) was chosen as an inside mark material, because it has only one strong absorption peak at 2100 cm(-1) and the peak was chosen as a quantitative peak of KSCN. The peak at 580 cm(-1) is the characteristic absorption of the wreath vibration of beta-CD and was chosen as a quantitative peak of beta-CD. KSCN and beta-CD were mixed with a certain quantity ratio and the mixture was analyzed by IR. The work curve of IR was established. A kind of new experimental method of measuring host/guest ratio of the IC was provided.

Calorimetry, Differential Scanning↗

PubMed2006

[Indirect ELISA for the pyrethroids-permethrin residue detection].

In order to detect the permethrin (Py) residue in environment samples, Ovalbumin(OVA)was used as protein carrier to couple with semi-antigen permethrin by active ester method. Indirect competitive ELISA (icELISA) was established. The most appropriate titration of coating antigen was 0.45 microg/mL and optimal dilution was 1/2 500 correspondingly. The standard curve of icELISA was also established and the curve indicated that the lowest detection limit was 0.l microg/mL, the curve had a favorable linear relation with the concentration range of 10 to approximately 800 microg/mL, recoveries of permethrin (>97%) were satisfactory.

Enzyme-Linked Immunosorbent Assay↗

PubMed1991

[Effect of permethrin selection on the developmental cycle and fertility of cockroaches (Blattella germanica)].

Each generation of Blattella germanica were treated with a dose of 0.42 microgram permethrin per VI instar larva. The fecundity varied from 8.21 to 33.66 for I instar larvae per female. Reproduction was significantly lower than that evaluated for untreated insects in third and fourth generations, but significantly higher in the fifth generation. Mortality among insects treated with permethrin, with the exception of the fourth generation only, was higher than among untreated cockroaches. In the third, fourth and fifth generations, the biotic potential was significantly lower in groups of treated insects than in untreated ones. The length of the developmental period of B. germanica treated with permethrin, measured during 7 generations, showed no significant changes in comparison with the control groups.

Animals↗

PubMed1987

Reduction in incidence and prevalence of Plasmodium falciparum in under-5-year-old children by permethrin impregnation of mosquito nets.

The malaria incidence and prevalence rates among children who slept under permethrin-impregnated mosquito nets in four villages near Madang, Papua New Guinea, were compared with the rates among children who slept under unimpregnated nets in four paired control villages. Immediately following a parasitological survey in the eight villages, malaria parasites were cleared from the children with chemotherapy, and the mosquito nets in the four experimental villages were impregnated with permethrin. Follow-up parasitological surveys were performed 4 and 10 weeks later. Sporozoite rates in female mosquitos of the Anopheles punctulatus complex decreased significantly in two of the experimental villages after impregnation. Also, the incidence of Plasmodium falciparum between the 4-week and 10-week surveys was significantly lower among the 0-4-year olds in villages with impregnated nets than in those with unimpregnated nets, leading to reduced prevalence of P. falciparum in this age group. Use of permethrin-impregnated nets had no effect on the incidence or prevalence of P. falciparum among 5-9-year olds or on that of P. vivax among the 0-4- or 5-9-year olds.

Animals↗

PubMed1985

Effects of 5,5-diphenylhydantoin (phenytoin) on neurobehavioral toxicity of organochlorine insecticides and permethrin.

Rats were given various doses of chlordecone, 1,1,1-trichloro-2,2-bis(p-chloro-phenyl)ethane (DDT) and lindane and tested for neurobehavioral toxicity up to 24 hr postdosing. The organochlorines either had no effect or increased responsiveness to an acoustic stimulus at subconvulsant doses. Only chlordecone and p,p'-DDT produced tremor. For purposes of comparison, the neurobehavioral effects of permethrin were also studied; this pyrethroid insecticide produced tremor and hyperresponsiveness similar to that of p,p'-DDT. Pretreatment with phenytoin significantly reduced the tremor and hyperresponsiveness produced by p,p'-DDT and permethrin. On the other hand, pretreatment with phenytoin increased the responsiveness of animals dosed with chlordecone or lindane, suggesting that these agents differ in their mechanism of action from p,p'-DDT and permethrin. The results of our experiments also indicate that care should be taken in the choice of agents, particularly anticonvulsants, to be used to treat symptoms of insecticide toxicity.

Animals↗

PubMed1984

The evaluation of a new synthetic pyrethroid pesticide (permethrin) for neurotoxicity.

A new synthetic pyrethroid, permethrin, has recently been granted a registration by the United States Environmental Protection Agency. Permethrin and a large number of other chemicals of its type are expected to receive widespread use in the environment in the near future. Since the mechanism by which these compounds exert their toxic effect in insects (and at higher doses in mammals) is by disruption of the normal function of nervous tissue, a detailed morphologic evaluation of the nervous system was performed on rats from two long-term feeding studies conducted on permethrin. In this evaluation, examination of central and peripheral nervous plus examination of extensive morphometric data and teased myelinated fibers of distal sural and tibial nerves and of the maxillary division of cranial nerve V did not reveal any changes which could be attributed to the feeding of the pesticide.

Animals↗

PubMed1994

[Assessment of resistance to permethrin of german cockroaches (Blattella germanica L.) caught in Poland].

Resistance to permethrin was tested in cockroaches caught in health service institutions in various parts of Poland. The tests were carried out by the contact method as recommended by the WHO. The density of the insecticide was 20 mg/m2. The experiment was done only on male insects, calculating the values of LT50 and LT90 in insect groups caught in various localities. These values were compared with LT50 and LT90 values in sensitive insects exposed to the insecticide, and the resistance indices R50 and R90 were calculated. This made possible determination of permethrin resistance of the populations from various areas. The results showed that the sensitivity of the insects varied. Cockroaches caught in Opole, Biała Podlaska, Szczecin, Warsaw were highly resistant to permethrin, while those from Płock, Piotrków Trybunalski, Chojnów, Nowy Sacz tolerated the insecticide, and those from Jedrzejów were as sensitive as control laboratory insects.

Animals↗

PubMed1993

The effect of permethrin impregnated sisal curtains on vector density and malaria incidence: a pilot study.

Impregnation of bednets and curtains with suitable pyrethroids may reduce entomological inoculation rates (EIR) and malaria incidence. We conducted a quasi-experimental pilot study over 3 months in Western Kenya on 20 houses with 54 children. Ten houses in the experimental site received sisal curtains treated with permethrin at either 0.5g/m2 or 0.1g/m2. Control houses had untreated curtains or none. Mosquito vector density (MVD), man biting rates (MBR), and residual insecticidal effects (RIE) of permethrin were determined every two weeks. MVD was reduced by 97.7% and 98.7% in houses from the 2 experimental groups with a 60% reduction with unimpregnated curtains. MBR varied from 6.4 (no curtains), 1.7 (unimpregnated), 0.7 (0.5g/m2 curtains) to 0.4 (1.0g/m2 curtains). RIE begun to decline after the fourth month. Malaria incidence remained similar at the two sites. We conclude that covering of eaves and windows with permethrin impregnated sisal curtains can reduce MVD and the number of mosquito bites to individuals sleeping in protected houses.

Animals↗

PubMed1994

Effects of permethrin-impregnated bed nets on malaria vectors of northern Guatemala.

The authors evaluated the effects on malaria vectors of bed nets impregnated with permethrin over the course of a 16-month controlled study in four communities of Northern Guatemala. Anopheles albimanus and An. vestitipennis were the known malaria vectors in the area. Households were allocated to one of three experimental groups: those receiving bed nets impregnated with 500 mg/m2 of permethrin, those receiving untreated bed nets, and those where no intervention measures were taken. The impact of the treated and untreated bed nets on mosquito abundance, behavior, and mortality was determined by indoor/outdoor night-bite mosquito collections, morning pyrethrum spray collections, inspection of bed net surfaces for dead mosquitoes, and capture-release-recapture studies. The duration of the treated nets' residual insecticide effect was assessed by modified WHO cone field bioassays, and their pyrethrin content was estimated by gas-liquid chromatography analysis. The most important observation was that fewer mosquitoes were found to be resting in the households with treated bed nets. The treated nets probably functioned by both repelling and killing vector mosquitoes. Capture-release-recapture studies showed exit rates from houses with treated nets were higher (94%) than those from control houses (72%), a finding that suggests repellency. However, no significant differences were noted between the indoor night-bite mosquito collections at houses with and without treated nets. The horizontal surfaces of treated bed nets were nearly 20 times more likely to contain dead anopheline mosquitoes than were the comparable surfaces of untreated nets. the bioassays indicated that unwashed permethrin-impregnated bed nets retained their insecticidal activity for 6 months after treatment.

Animals↗

PubMed1993

Treatment of human scabies by sulfur and permethrin.

Scabies is one of the most important prevalent contagious disease caused by itch mite "Sarcoptes scabiei." Many effective scabiecides have been suggested and tried. They differ in their side effects since they are applied on diseased skin sometimes all over the body. In this paper, sixteen parasitologically proved human scabies were successfully treated by 5% sulfur precipitate and 2.5% permethrin. Application of sulfur for one week or 2 applications of permethrin followed by a third one a week later proved to be safe and effective. The one week course of sulfur and the third application of permethrin acts against any emerging immature stages of the mite.

Follow-Up Studies↗

PubMed1996

Contact toxicity of permethrin-impregnated military uniforms to Culex pipiens (Diptera:Culicidae) and Phlebotomus papatasi (Diptera: Psychodidae): effects of laundering and time of exposure.

The effects of laundering and time of exposure on the insecticidal activity of military uniform fabric impregnated with permethrin at 0.125 mg active ingredient (AI)/cm2 are reported from susceptibility tests with laboratory-reared mosquitoes, Culex pipiens, and sand flies, Phlebotomus papatasi. Knockdown/mortality resulting from exposure of groups of female insects for periods of 1, 3, 5, 7, and 10 min was recorded and compared among 5 different treatment/wash groups (untreated/unwashed, treated/unwashed, treated/1-wash, treated/2-wash, treated/3-wash). Laundering was by machine washing with detergent and warm water followed by hot-air machine drying. Post-exposure assessments at intervals from 0 to 60 min and at 24 h showed that knockdown for each exposure time and wash group was initially low but increased steadily during the first hour post-exposure. Sand flies were less sensitive than mosquitoes to knockdown during the first 60 min after contact with treated/unwashed fabric; however, 24-h mortality rates for sand flies were higher as compared with mosquitoes. The permethrin remaining after a 3rd wash had little knockdown effect on mosquitoes but was toxic to sand flies at each of the 5 exposure times. Significant reductions in the knockdown effectiveness of permethrin-treated fabric to mosquitoes and sand flies was associated with single and repeated washings of the fabric.

Animals↗

PubMed1996

Rapid decomposition of permethrin in the outer fly of an experimental tent in Pakistan.

The residual activity of permethrin on the canvas of an experimental tent, used by nomadic refugees in a malarious area in northern Pakistan, was assessed. A permethrin emulsion sprayed on the inner sheet of a pitched double-fly tent (0.5 g/m2) had an effective residue for at least 6 months in bioassays using the local malaria vectors, Anopheles stephensi and Anopheles culcifacies. However, a high concentration of permethrin (2 g/m2) sprayed on the inner surface of the outer tent, simulating single-fly tents, decomposed within 2 months. These findings were confirmed with chromatographic analysis. Under the conditions found in the study area, the shortened residual effect most likely resulted from photodecomposition, not previously reported to affect operational performance of this insecticide.

Animals↗

PubMed1996

Malaria control using permethrin applied to tents of nomadic Afghan refugees in northern Pakistan.

Malaria control among nomadic populations has, in the past, posed serious logistic difficulties. Presented in this article are the results of a pilot study in which permethrin was sprayed on the tents of over 26000 nomadic Afghan refugees in an area of Pakistan where seasonal malaria outbreaks occur. In this area Anopheles culicifacies and A. stephensi are the malaria vectors. Population surveys in the year of the study, before and at the end of the transmission season, showed that the increase in the Plasmodium falciparum prevalence among the Afghan nomads was on average significantly less (increase from 6.4% to 15.3%) than that among the resident Pakistani population (from 3.2% to 45.6%). Surveys at the end of the transmission season among primary schoolchildren the year before and the year of the permethrin trial showed that the P. falciparum prevalence among nomadic children decreased significantly (from 46.9% to 16.3%), whereas an increase was observed among the local Pakistani children. The results show that spraying tents with permethrin was a safe and culturally acceptable intervention for the Afghan refugees and that the findings warrant further investigation.

Adolescent↗

PubMed1996

Response of Anopheles farauti to permethrin-treated net and cloth fabrics in the laboratory.

The median effective dose of permethrin for knockdown and mortality of Anopheles farauti s. s. exposed to 2 net and 2 cloth fabrics was estimated. There were no significant differences in the knockdown or mortality of An. farauti or Aedes aegypti following 15-180-sec exposure to permethrin-treated bed nets and polyester/cotton fabric. Despite the presence of permethrin (0.007-0.068 mg/cm2) in bed net material, 18.2-50% of An. farauti adults successfully obtained a blood meal through the nets, and although all of them were knocked down after 60 min, up to 77.8% recovered within 24 h and 57.1-100% of the survivors were bloodfed. The results indicate that this important vector of malaria can obtain a blood meal through treated bed net material and emphasizes the importance of avoiding contact with the net while sleeping.

Aedes↗

PubMed1996

[Toxicologic evaluation of pyrethroids in indoor air: demonstrated with the example of cyfluthrin and permethrin].

Pyrethroids have varying activities depending on vehicle or route of administration (oral, dermal, inhalational). Specific features like the sensory irritation potential of the alpha-cyano-pyrethroids on the respiratory tract can only be quantified adequately by inhalation testing. Thus equitoxic dosages can vary between inhalative and oral application, especially for alpha-cyano-pyrethrolds. The no-effect values for chronic exposures derived for permethrin (type I pyrethroid) and cyfluthrin (type II pyrethroid) show clearly, that each pyrethroid has to be considered as an individual substance toxicologically, and that any extrapolation from the oral to the inhalative route should only be done after a thorough assessment of the specific toxicological profile. The study of simulated pest control measures on carpets pretreated with permethrin showed, that no significant enrichment of permethrin in total dust could be seen from a carpet additionally treated with pyrethroids. The missing correlation between absolute (mg pyrethroid/m3 air) and relative (mg pyrethroid/kg dust) concentrations in air-borne dust as well as the low degree of translocation of pyrethroids from carpets (only about 0.044% x m(-2) x h(-1) of the cyfluthrin applied to the carpet can be regarded as possibly respirable) prove, that analyses of pyrethroids in household sedimented dust ("vacuum cleaner bag analyses") without knowing the absolute surface concentration and respective air concentrations are of little value for risk assessment. The data allow the conclusion, that a scientific assessment of health risks is only possible based on absolute concentrations of pyrethroids in indoor air.

Air Pollution, Indoor↗

PubMedDate not supplied

[Impregnation of uniforms with permethrin as a mean of protection of working personnel exposed to contact with hematophagous arthropods].

Laboratory bioassays were conducted to evaluate the effectiveness of permethrin-impregnated clothing against biting arthropods. Military battle dress uniforms were impregnated at a rate of 0.12-0.15 mg active ingredient (A.I.)/cm2. Gas chromatographic analysis of cloth patches treated showed that over 50% of the chemical remained after 6 cycles of washing. This amount of A.I. (0.06-0.07 mg/cm2) was effective in providing protection against Aedes aegypti and Ixodes ricinus. Mosquitoes and ticks were exposed respectively for 30 sec-3 min and 5-10 min to permethrin-impregnated uniforms: although the knockdown effect diminished with washing, the remaining permethrin provided 100% mortality of the mosquitoes and over 90% mortality of the ticks.

Aedes↗

PubMed1996

Factors Influencing Pyrethroid Resistance in a Permethrin-Selected Strain of the Soybean Looper, Pseudoplusia includens (Walker)

Cytochrome P450 monooxgenase activity toward p-nitroanisole was measured in larvae of three strains of soybean looper, Pseudoplusia includens (Walker), including a laboratory susceptible (S) strain, a resistant (R) strain selected for several generations with permethrin, and a nonselected (NS) strain from the same field collections as the R strain. Activity was significantly higher in R strain larvae than in the S and NS strains (1.8- and 1.4-fold, respectively), and there was no significant difference between activity in the S and NS strains. Resistance to the alpha-cyano pyrethroids deltamethrin and cypermethrin was similar to or higher than that observed with permethrin (RR = 70.0, 62.4, 145.3 and 12.1, 32.3, and 27.0 for permethrin, deltamethrin, and cypermethrin in R and NS strains, respectively). The R strain was less resistant (RR = 4.3) to tefluthrin, a pyrethroid with a fluorinated-phenyl alcohol moiety, and a nonester (ether) pyrethroid, BRC 429 (RR = 17.7). Piperonyl butoxide (PB) significantly increased the toxicity of each insecticide tested in the R and NS strains. In addition, penetration of 14C-cypermethrin was decreased significantly at 24 hr after treatment when R strain larvae were pretreated with PB, with 21.1% of the applied dose unpenetrated in PB-treated larvae and 7.6% unpenetrated in larvae not treated with PB.

Journal Article↗