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PubMed1980

Treatment of public lice infestation: a comparison of two agents.

Bulletins issued by both the United States Public Health Service and the Pan American Health Organization have noted a sharp increase in the incidence of public lice infestation (pediculosis pubis) in this country. At the Haight-Ashbury Free Medical Clinic we conducted a controlled, open study comparing the efficacy and safety of Kwell Shampoo (gamma benzene hexachloride; lindane) with RID, an over-the-counter, pyrethrin-based pediculicide. The results showed the two treatments to be equally effective and safe. All adult lice, nymphs, and nits were eradicated at the one week follow-up in fifteen patients treated with single applications of either product. Two patients in each group experienced very slight and transient erythema.

Administration, Topical↗

PubMed1984

Head-lice infestations and their treatment.

Head-lice infestations periodically cause disruption at schools and crèches. The life cycle of the insect and the treatment of infestation are discussed. Treatment is usually relatively simple and effective, relying mainly on the use of insecticides such as gamma benzene hexachloride, malathion and pyrethrins. Appropriate therapy for problem areas, for example the eyebrows, is also described.

Anoplura↗

PubMedDate not supplied

Species and structural variations affecting pyrethroid neurotoxicity.

Pyrethroids provide fascinating patterns and examples of species selectivity resulting from variations in nerve sensitivity and detoxification rates. Three classification systems are useful in considering pyrethroids: origin, structure, stability and use relative to the natural pyrethrin I; lethal and sublethal or knockdown agents; Types I and II symptoms and nerve action. Pyrethroid-detoxifying esterases and oxidases contribute importantly to the species and strain specificity and provide an opportunity to use inhibitors as synergists for improved effectiveness. Pyrethroids are potent and selective neuropharmacological agents inducing repetitive discharges or conduction block in a variety of sensory and motor nerves and in the CNS. Small structural modifications in the pyrethroid often change the type of action as well as the potency and species specificity. Pyrethroid resistance in selected strains of insect pests may involve a modified and pyrethroid-insensitive target site.

Animals↗

PubMed1993

[Pediculosis capitis: a questionnaire survey in 4 schools of the Bordeaux Academy 1990-1991].

A questionnaire survey of head lice treatment was conducted in four schools--each including a nursery and an elementary school--in the Bordeaux area. Two schools were situated in the centre of the city, one in a suburban area and one in a rural area (50 km from the city). Four-page questionnaires were filled in anonymously by the parents in April 1991; 840 answers were obtained (80 p. 100 response rate). Between January 1990 and March 1991, 48.7 p. 100 of children had at least one episode of head lice infestation (infestation rates varied from 38.8 to 62.6 p. 100 depending on the schools); 30.5 p. 100 of children were contaminated for the first time during that period. Lice were detected by the parents in 95 p. 100 of the cases. The prevalence of lice was higher in females (60 p. 100) than in males (40 p. 100). The highest prevalence was noted in the suburban school where 17 p. 100 of the parents were unemployed at the time of the survey. The peak age for head lice was 7, but 19.4 p. 100 of nursery school children aged 2-4 years had been contaminated at least once. Impetigo was rare (1.2 p. 100), and pruritus was noted in only 14.2 p. 100 of the cases. Most children had been contaminated at school. Curative treatment was counselled by a chemist in 87 p. 100 of the cases. Pyrethrins were used in 81 p. 100, and the shampoo (Hegor) plus spray (Paraspecial Poux) association was the most frequent, totalling two-thirds of prescriptions.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗

PubMed1994

Do mosquito coils and killer sticks work against Anopheles gambiae sensu lato mosquitoes in Zimbabwe?

Tests against Anopheles gambiae s. 1. mosquitoes (malaria transmitting mosquitoes) were carried out in Chegutu, Chiredzi and Kamhororo (Gokwe). These tests were done in relatively closed rural huts and experimental huts. The tests demonstrated that a one hour exposure to smoke from the burning of insecticidal coils contain 0.3 pc pyrethrin, achieve 100 pc knockdown of mosquitoes. Mosquito killer sticks gave 85 pc knockdowns with 30 pc recoveries and less than 10 pc recoveries for the coils. With caged insects in Gokwe the KD50 for both the coils and sticks was been 15 to 20 minutes and the KD90 ranged from 40 to 50 minutes. The coils were observed to more lethal than the sticks. Mortalities were 100 pc for the coils and 85 pc for the killer sticks after a 24 hour holding period.

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↗

PubMedDate not supplied

Determination of pyrethroid residues in vegetables, fruits, grains, beans, and green tea leaves: applications to pyrethroid residue monitoring studies.

Determination of natural pyrethrins and 12 synthetic pyrethroids in agricultural products was investigated. Vegetables and fruits were extracted with acetone, filtered after addition of coagulating solution, partitioned into n-hexane, and cleaned up on a Florisil column (as necessary). Pyrethroids were determined by gas chromatography/electron capture detection (GC/ECD) by using a methyl silicone-coated fused-silica capillary column, and recoveries were calculated by summing peak areas of the components. GC/mass spectrometry was used to identify the pyrethroids detected by GC/ECD monitoring. Grains and beans containing lipids were analyzed by extraction with acetonitrile, partition into n-hexane, Florisil column cleanup, and capillary GC/ECD. The coagulation method was suitable for nonfatty crops such as vegetables, fruits, and green tea leaves, because recoveries were good and Florisil column cleanup was not needed in most cases. The coagulation method was not applicable to lipid-containing crops such as grains and beans because of low recoveries. Recoveries for 18 crops at fortification levels of 0.25-1.0 ppm were 60.0-103.5%. No pyrethroids were detected from the nonfortified crops tested except green tea leaves, in which fluvalinate was detected at 0.89 ppm.

Chromatography, Gas↗

PubMed2001

Monitoring insecticide resistance in house flies (Diptera: Muscidae) from New York dairies.

House flies were collected from dairies across New York state and the levels of resistance to seven insecticides were measured using standard laboratory assays with three to five diagnostic concentrations. The highest levels of resistance were found for tetrachlorvinphos, permethrin and cyfluthrin. Although levels of resistance to methomyl were somewhat lower, they were among the highest ever reported for field-collected house flies. Resistance to pyrethrins was limited primarily to the lowest diagnostic concentration. House flies were susceptible to fipronil at all dairies, suggesting that this material would be highly effective for fly control. The levels of resistance were similar at all the dairies, irrespective of their insecticide use, suggesting substantial movement of flies between facilities. Relative to resistance levels found at New York dairies in 1987, resistance levels had increased for permethrin, were unchanged for tetrachlorvinphos and had decreased for dimethoate. To identify a single diagnostic concentration that could be used in the laboratory assays to assess accurately resistance levels in future studies, we carried out a 'simulated' field bioassay using formulated materials. A diagnostic concentration for each insecticide is proposed on the basis of a comparison of our bioassays.

Adaptation, Physiological↗

PubMed1987

Compatibility of Metarhizium anisopliae var. anisopliae with chemical pesticides.

The effects of various insecticides on the mycelial growth, sporulation and conidial germination of Metarhizium anisopliae var. anisopliae isolate E9 were studied in the laboratory. Chlorpyrifos was the most toxic organophosphate to mycelial growth and sporulation at all concentrations. Temephos, malathion and leptophos were highly toxic to sporulation while malathion was the most inhibitory to germination. The carbamates, carbofuran, methomyl and oxamyl were moderately toxic to mycelial growth and sporulation while oxamyl had an adverse effect on germination. The pyrethroids (pyrethrin, permethrin and resmethrin) and the insect growth regulators (diflubenzuron and methoprene) were not inhibitory to the various developmental stages of isolate E9. The chlorinated hydrocarbons (chlordane, lindane and toxaphene) were more deleterious than all other insecticide groups tested. Among the fungicides, benomyl and maneb produced the greatest inhibition.

Drug Resistance, Microbial↗

PubMed2026

Evaluation of the effects of domestic tomato processing on biopesticide residue using natural deep eutectic solvents (NADES) extractions.

The present study evaluated the fate of fourteen botanical biopesticides in processed tomato samples. Various processing methods were employed, including washing, dehydration, and the preparation of juice and sauce. The extraction was performed using more sustainable techniques, aimed at minimizing the environmental impact of conventional organic solvents by substituting them with natural deep eutectic solvents (NADES). Solid-liquid extraction (SLE) and dispersive liquid-liquid microextraction with solidification of floating organic drop (DLLME-SFOD) were utilized for solid and liquid tomato samples, respectively. The NADES used was choline chloride:2,3-butanediol (ChClBt) at a 1:4 molar ratio for both techniques, resulting in recovery values ranging from 69.2 to 106.2% for SLE, and extraction efficiencies reaching up to 46.2% for DLLME-SFOD. The impact of these processes was evaluated employing the processing factor (PF), yielding PF values of less than 1 in all cases. Compounds as pyrethrins, azadirachtin, and rotenone persisted after processing, posing a potential consumer risk.

Solanum lycopersicum↗

PubMed1986

Management of acute childhood poisonings caused by selected insecticides and herbicides.

Most childhood exposures to insecticides and herbicides do not result in poisonings. Decontamination and observation are usually adequate treatments. The most frequent exposures involve carbamate and organophosphate insecticides. These compounds inhibit acetylcholinesterase, resulting in cholinergic signs that are reversible with atropine administration. Recent reports from poison control centers indicate that organophosphates have been associated with most of the serious childhood poisonings. Pralidoxime, a cholinesterase reactivator, must be administered along with atropine to patients with serious organophosphate poisoning, to reverse nicotinic receptor effects--in particular, respiratory paralysis. Although carbamates and organophosphates may cause clinically indistinguishable physical signs, pralidoxime therapy may be contraindicated for carbamate intoxications. In the event of a serious poisoning caused by a combination of organophosphate and carbamate insecticides, or by an unknown cholinergic agent, pralidoxime should not be withheld. Many organochlorine insecticides are restricted or are no longer available in the United States. CNS excitation and seizures, manifestations of organochlorine intoxication, can occur following ingestion or inappropriate application of the 1 per cent topical formulation of lindane used to treat scabies and lice. Treatment of such intoxication consists of decontamination measures and anticonvulsant administration. Pyrethrins are generally nontoxic in doses commonly ingested. Individuals with an allergic history may be at greatest risk for the most common adverse effects, contact dermatitis and hypersensitivity reactions. Of all insecticides or herbicides, paraquat is the most toxic. Any exposure to paraquat must be evaluated, even if several days have passed since the herbicide was ingested. Signs of pulmonary status deterioration usually portend a grave prognosis in paraquat poisoning. Despite in vitro toxicity similar to paraquat, diquat does not cause lung effects in human poisonings, and reported deaths have been from other causes. Poisoned patients who receive appropriate and timely treatment are virtually assured of complete recovery from most insecticide and herbicide poisonings. Deaths and long-term sequelae most often result from respiratory complications, which may occur as complications of the intoxication or from other constituents in the insecticide or herbicide formulation. Good supportive care with meticulous attention to, and anticipation of, respiratory complications is absolutely essential to prevent long-term sequelae or death from hypoxia.(ABSTRACT TRUNCATED AT 400 WORDS)

Absorption↗

PubMed1996

Cytogenetic effects of piperonyl butoxide and safrole in CHO-K1 cells.

Recently, hepatocarcinogenicity in rats and mice was reported with regard to the methylenedioxyphenyl compound, piperonyl butoxide (PB), which is used as a synergist for pyrethrins and related insecticides. Induction of sister-chromatid exchanges (SCEs) and chromosomal aberrations (CAs) due to PB were investigated using CHO-K1 cells with or without rat liver S9 fraction (S9); at the same time, the effects of safrole (SF), a methylenedioxyphenyl compound and a weak hepatocarcinogen, were also examined. PB (0.25 and 0.3 mM) and SF (0.8 mM) caused a slight but significant increase in SCEs followed by a cell-cycle delay in the 3-h treatment without S9. In the presence of S9 (4.5%), the cytotoxicity of PB or SF was weakened greatly or slightly, the top dose capable of cell division was raised to 0.6 mM (2-fold) or 1 mM, respectively. PB with S9 induced SCE at doses of 0.4 and 0.5 mM, and caused endoreduplications (ERDs, 7%) at a dose of 0.6 mM, while SF caused a dose-related significant increase in SCE at all doses used (0.4-1 mM) with S9. Genotoxicity of the metabolites of PB or SF was cleared by changing the dose of S9 (1.5-9%) while holding the dose of each chemical constant. In the case of SF (0.6 mM), induction of SCE, ERD and cell-cycle delay intensified almost in a dose-effect relationship, and CAs and a high level of ERD (14%) were caused by a 9% dose of S9. The concentration of unchanged SF in the incubated medium was certainly in inverse proportion to the dose of S9. This strongly suggests that the metabolites of SF are genotoxic. In the case of PB (0.3 mM), no positive responses were produced in the cultures, even with a high level of S9, though the amount of unchanged PB left in the incubated medium was very slight. This indicates that the metabolites of PB may not be genotoxic. In conclusion, PB and SF are possible to somewhat induce SCE at high dose(s) in the absence of S9, and the genotoxic effects of SF are more intensified in the presence of S9 than in its absence, while PB is probably no genotoxic in the presence of sufficient metabolic activation.

Animals↗

PubMed1981

Treatment of scabies and pediculosis with lindane preparations: an evaluation.

Risks and benefits involved in the use of lindane preparations for the treatment of scabies and head louse infestations are evaluated. Although lindane per si is moderately toxic, capable of inducing neurotoxic and hemotoxic effects, there is little evidence that the preparations used in the treatment of scabies and pediculosis give rise to toxic symptoms when applied according to directions. Current evidence does not support the view that lindane is intrinsically carcinogenic, although very high doses have induced hepatomas in mice. It is concluded that the benefits obtained in the use of lindane as a scabicide and pediculicide outweigh risks involved in its use for these purposes. Comparison with other preparations available for the control of scabies and pediculosis indicate that lindane is probably the most effective scabicide, although it also shows the greatest toxic potential. Malathion and pyrethrin preparations seem equally effective against head lice. Suggestions for even safer use of lindane are discussed.

Animals↗

PubMed2000

Efficacy and safety of selamectin against fleas on dogs and cats presented as veterinary patients in Europe.

Two controlled and masked multi-centre studies were conducted to examine the efficacy of a novel topical avermectin, selamectin, against natural flea infestations on 418 dogs and 345 cats. Veterinary patients with viable flea infestations were enrolled in the studies, which were conducted in United Kingdom, France, Germany, and Italy. Animals were allocated randomly in a 2:1 ratio to one of two treatments: either selamectin alone at a minimum dosage of 6mgkg(-1) or fenthion at recommended dose rates. Concurrent use of an environmental spray (containing methoprene and either pyrethrins or permethrin) was permitted only for fenthion-treated animals. In-contact cats and dogs (animals living in the same home) received the same treatment as the first animal enrolled from the household, if recommended by the veterinarian. Study day 0 was defined as the day of first treatment. Animals were treated on days 0, 30, and 60, and flea comb counts and clinical evaluations were conducted on days 0, 14, 30, 60, and 90. Analysis of variance of ln(flea count+1) showed that values were significantly lower for selamectin alone compared with fenthion (with or without the concurrent use of an environmental spray) in dogs on days 30, 60, and 90 (P<0.05) and in cats on days 14, 30, 60, and 90 (P<0.01). For selamectin, the reductions in geometric mean flea counts on days 14, 30, 60, and 90, compared with day 0, were 92.5, 90.7, 98.1, and 99.1%, respectively, for dogs and 92.8, 92.7, 97.7, and 98.4%, respectively, for cats. Selamectin was shown to be safe and highly effective in the control of naturally acquired flea infestations on dogs and cats presented as veterinary patients in Europe.

Animals↗

PubMed1998

Comparative efficacy of pyrethrum marc with albendazole against sheep gastrointestinal nematodes.

The efficacies of pyrethrum marc and of albendazole against experimental sheep gastrointestinal nematode infection were compared. Sheep was infected orally with 10,000 larvae (Haemonchus spp. (60.1%), Oesophagostomum spp. (13.9%), Trichostrongylus spp. (13.2%), Cooperia spp. (8.3%), Nematodirus spp. (3.5%), Strongyloides spp. (0.8%) and Ostertagia spp. (0.2%). Faecal egg count reduction in albendazole-treated sheep was 100% by day 4 following treatment, compared to 37.03%, 31.3%, 38.9% and 51.8% on days 4, 6, 8 and 10 in pyrethrum mare-treated sheep. These reductions were statistically significant on days 8 and 10 post-treatment (p < 0.05). The potential for using pyrethrins for helminth treatment is discussed.

Albendazole↗

PubMedDate not supplied

Pesticide storage and use patterns in Minnesota households with children.

As part of the National Human Exposure Assessment Survey (NHEXAS), residential pesticide storage and use patterns were evaluated in a population-based sample of Minnesota households with children aged 3-13. In-home interviews and inventories were conducted to identify pesticide products stored and used in and around 308 households. This statistically based sample represents more than 49,000 urban and rural households in the census tracts sampled. More than 850 unique products were identified using Environmental Protection Agency (EPA) registration numbers. Pesticide products were found in 97% and reported used in 88% of study households. Population-weighted mean values for pesticide storage and use were 6.0 and 3.1 products per household, respectively. The most common active ingredients found were diethyl toluamide (DEET) and related compounds, piperonyl butoxide, pyrethrins, dimethylamine 2-[2-methyl-4-chlorophenoxyl propionate (MCPA) and chlorpyrifos. Household socio-demographic characteristics explained little of the variability in pesticide storage and use patterns, and there were no significant differences in residential storage and use patterns between households located in urban versus non-urban census tracts. Although the prevalence of households with pesticide products was similar to recent national surveys, observed storage and use rates were almost twice those obtained in recent national studies, reflecting improved inventory techniques used by this study and/or increased rates of pesticide presence and use in study households.

Adolescent↗

PubMed1997

Head louse infestations: epidemiologic survey and treatment evaluation in Argentinian schoolchildren.

BACKGROUND: Our aim was to demonstrate that the treatment of individual cases is effective, but not sufficient, to control endemic Pediculus capitis, and that eradication of the epidemiologic school focus may lower significantly the prevalence of infestation. Statistical data on the degree of infestation relating to socio-economic and cultural variables were also updated. Therapeutic effects and educational impact were evaluated. METHODS: An educational and motivational program was designed for pupils, parents, and teachers: 326 children and 15 adults were subjected to clinical and parasitologic evaluation. The recorded parameters included the age, sex, hair style and length, presence of other dermatologic diseases, degree of infestation, clinical remission, parasitologic remission, dwelling type and features, need to share a bed with co-dwellers, availability of home tap water supply, level of family income, and periodic medical controls. The entire population received treatment with neutral shampoo and rinsing cream containing 1% permethrin. Exclusion criteria were the presence of acute scalp inflammation and a history of pyrethrin and/or pyrethroid sensitivity. Statistical analysis was performed as required on data expressed as frequencies, percentages, means, and standard deviations by chi-square and Fisher exact tests. RESULTS: The overall infestation prevalence rate was 81.5%, the highest values corresponding to children from 6 to 11 years of age, with a slight predominance in males (55.4% vs. 44.6%). A significantly greater rate of clinical remission was observed in subjects enjoying home tap water supplies (p < 0.01). CONCLUSIONS: The model of research plus action adopted allows the following conclusions to be drawn: (i) individual and isolated treatments for pediculosis are useful, but will not by themselves allow for the epidemiologic control of this parasitosis; (ii) massive, complete, and simultaneous treatments lead to a significant decrease in infestation prevalence; (iii) educational measures tending to foster collective awareness enable greater epidemiologic surveillance to be achieved; (iv) careful inspection of the entire scalp is essential with the use of a powerful light source and lenses with high magnification, as the parasite has no predilection for any given area; (iv) socio-economic and cultural conditions are not relevant for infestation, although a good home tap water supply is essential for treatment.

Adolescent↗

PubMed2001

Chrysanthemyl diphosphate synthase: isolation of the gene and characterization of the recombinant non-head-to-tail monoterpene synthase from Chrysanthemum cinerariaefolium.

Chrysanthemyl diphosphate synthase (CPPase) catalyzes the condensation of two molecules of dimethylallyl diphosphate to produce chrysanthemyl diphosphate (CPP), a monoterpene with a non-head-to-tail or irregular c1'-2-3 linkage between isoprenoid units. Irregular monoterpenes are common in Chrysanthemum cinerariaefolium and related members of the Asteraceae family. In C. cinerariaefolium, CPP is an intermediate in the biosynthesis of the pyrethrin ester insecticides. CPPase was purified from immature chrysanthemum flowers, and the N terminus of the protein was sequenced. A C. cinerariaefolium lambda cDNA library was screened by using degenerate oligonucleotide probes based on the amino acid sequence to identify a CPPase clone that encoded a 45-kDa preprotein. The first 50 aa of the ORF constitute a putative plastidial targeting sequence. Recombinant CPPase bearing an N-terminal polyhistidine affinity tag in place of the targeting sequence was purified to homogeneity from an overproducing Escherichia coli strain by Ni(2+) chromatography. Incubation of recombinant CPPase with dimethylallyl diphosphate produced CPP. The diphosphate ester was hydrolyzed by alkaline phosphatase, and the resulting monoterpene alcohol was analyzed by GC/MS to confirm its structure. The amino acid sequence of CPPase aligns closely with that of the chain elongation prenyltransferase farnesyl diphosphate synthase rather than squalene synthase or phytoene synthase, which catalyze c1'-2-3 cyclopropanation reactions similar to the CPPase reaction.

Amino Acid Sequence↗