SEARCH · Search PubMed

Results for “INSECTICIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources

PubMed2005

Evaluation of long-lasting insecticidal nets after 2 years of household use.

Development of long-lasting insecticidal nets (LLINs) may eliminate the need for insecticide retreatment of ITNs. While two LLINs (Olyset, Sumitomo Chemical Co., Japan; and PermaNet 1.0, Vestergaard-Frandsen, Denmark) have received recommendations from the World Health Organization Pesticide Evaluation Scheme, field-testing under normal use has been limited. We used a survival analysis approach to compare time to net failure of conventional polyester bednets treated only with deltamethrin to two LLINs and two candidate LLINs (Olyset; PermaNet; Insector, Athanor, France; and Dawa, Siamdutch Mosquito Netting Co., Thailand). Additionally, we evaluated nets treated with a process designed to increase the wash-durability of permethrin-treated nets through the addition of cyclodextrin (a starch) in the treatment process. Houses in western Kenya were randomly assigned to one of the six net types and nets were distributed to cover all sleeping spaces. Households were visited monthly to assess reported side effects in inhabitants and washing frequency. Nets were evaluated for insecticidal activity by periodic WHO cone bioassays with mortality assessed at 24 h. Nets with bioassay mortality <70% were assayed monthly until failure, defined as the first of two consecutive bioassay mortality rates <50%. Time to failure was analyzed using an extended Cox Proportional Hazards model controlling for the cumulative number of washes. We distributed 314 nets to 177 households in June-July 2002; 22 nets (7.0%) were lost to follow-up and 196 (62.4%) failed during the first 2 years of the evaluation. Controlling for cumulative number of washes, PermaNet 1.0 [Hazard Ratio (HR) 0.14, 95% Confidence Interval (CI) 0.06-0.31] had a significantly lower risk of failure than conventional nets while Insector had a significantly higher risk of failure (HR 2.57, 95% CI 1.06-4.15). The risks of failure of the remaining nets (Olyset: HR 1.29, 95% CI 0.79-2.10; Dawa: HR 0.58, 95% CI 0.32-1.18; cyclodextrin: HR 0.65, 95% CI 0.40-1.1) were not significantly different from that of a conventional net. PermaNet 1.0 performed significantly better than conventional nets and should be recommended to malaria control programs.

Animals↗

PubMed2007

Delivery of insecticide-treated net services through employer and community-based approaches in Kenya.

BACKGROUND AND OBJECTIVES: Many approaches have been used to deliver insecticide-treated nets (ITNs) to African communities in different settings. Between 1992 and 2002, the African Medical and Research Foundation (AMREF), Kenya, used two ITN delivery models: the employer-based approach and the community-based approach. These two approaches have never been compared in order to inform their potential for future ITN delivery. We aimed to (1) compare the extent of ITN ownership, use and retreatment coverage in different population groups in the employer and community-based models and (2) identify options for improving people's acceptance and use of treatment/retreatment services. METHODS: Qualitative and quantitative methods for data collection and analysis. A total of 2095 household heads were interviewed in the quantitative study, while purposively selected groups and key informants participated in the qualitative study. RESULTS: Net coverage (both treated and untreated nets) and retreatment rates with insecticides were significantly higher at employer-based sites (54.3%) than at community-based sites (35.0%). Bed net ownership has increased significantly since the start of AMREF interventions in 1998 in employer-based sites (from 27% to 61.1%); in community-based sites, it has either decreased (urban area, from 29.0% to 16.5%) or increased (rural area, from 17.0% to 49.1%). Retreatment rates in all sites were negatively influenced by the lack of information, cash and availability of insecticides. Satisfaction with the form of payment and services delivered was higher in employer-based sites. This was attributed to employers providing credit for the purchase of nets and retreatment kits and the employers' medical teams giving information on malaria and making follow-up visits on workers who fell ill. CONCLUSIONS: Employer-based delivery of ITNs was more successful than community-based delivery in attaining both high coverage with ITNs and higher rates of net retreatment. Methods used for the retreatment of nets, forms of payment and communication strategies should be convenient to communities. Organized community groups may continue to play an important role in remote rural areas.

Adolescent↗

PubMed1987

gamma-Aminobutyric acid receptor ionophore complexes: differential effects of deltamethrin, dichlorodiphenyltrichloroethane, and some novel insecticides in a rat brain membrane preparation.

The binding of [35S]t-butylbicyclophosphorothionate ([35S]TBPS), a gamma-aminobutyric acid (GABA)-activated chloride ionophore ligand; [3H]diazepam, a benzodiazepine agonist; and [3H]muscimol, a GABA receptor probe, were used to assess the effects at 100 microM of deltamethrin, dichlorodiphenyltrichloroethane (DDT), and three experimental insecticides--a DDT-pyrethroid hybrid, GH414 (cycloprothrin), and two DDT-analogues, GH266 and GH149 (EDO), on GABA receptor ionophore complexes in a rat brain membrane preparation. GH266 and GH149 were found to inhibit a greater percentage of [35S]TBPS binding than the same concentration of deltamethrin or DDT, although GH414 had little effect. GH266 and GH149 enhanced [3H]diazepam binding by nearly 200%, in contrast to the inhibitory effects of deltamethrin, DDT, and GH414. GH266 and GH149 also caused a dramatic enhancement of [3H]muscimol binding, 367 and 236% of control, respectively, whereas DDT and deltamethrin caused only a moderate enhancement. The effects of the insecticides on binding affinity and density were examined for each of the ligands. The results show a differential interaction of the insecticides on the various ligand binding sites.

Animals↗

PubMed2006

Neonicotinoid insecticides display partial and super agonist actions on native insect nicotinic acetylcholine receptors.

Nicotinic acetylcholine receptors (nAChRs) are present in high density in insect nervous tissue and are targeted by neonicotinoid insecticides. Improved understanding of the actions of these insecticides will assist in the development of new compounds. Here, we have used whole-cell patch-clamp recording of cholinergic neurons cultured from the central nervous system of 3rd instar Drosophila larvae to examine the actions of acetylcholine (ACh) and nicotine, as well as the neonicotinoids imidacloprid, clothianidin and P-CH-clothianidin on native nAChRs of these neurons. Dose-response data yield an EC(50) value for ACh of 19 microm. Both nicotine and imidacloprid act as low efficacy agonists at native nAChRs, evoking maximal current amplitudes 10-14% of those observed for ACh. Conversely, clothianidin and P-CH-clothianidin evoke maximal current amplitudes up to 56% greater than those evoked by 100 microm ACh in the same neurons. This is the first demonstration of 'super' agonist actions of an insecticide on native insect nAChRs. Cell-attached recordings indicate that super agonism results from more frequent openings at the largest (63.5 pS) conductance state observed.

Acetylcholine↗

PubMed1985

Variation in cutaneous sensation between synthetic pyrethroid insecticides.

Synthetic pyrethroids are potent insecticides, utilized for food protection and general pest control. Numerous investigations have indicated that ultra-low volume applications are effective and may eliminate the developing problem of resistance to the currently utilized insecticides. The most prominent health symptom that accompanies topical contact with these agents appears to be a cutaneous sensation, paresthesia. In this investigation, a substantial difference in the degree of paresthesia was noted between the formulated grade of 4 synthetic pyrethroids. Also, dl-alpha tocopheryl acetate was statistically validated as an efficacious therapeutic agent for cutaneous exposure to these insecticides.

Administration, Topical↗

PubMed1976

Insecticides in human breast milk.

Fifty samples of human breast milk were analysed by gas chromatography and thin layer chromatography for DDT (dichlordiphenyltrichloraethan), hexachlorobenzol, benezene-hexachlorides, dieldrin, aldrin and heptachlorepoxide. The three first substances were found in all samples in amounts varying from quite small up to eleven times the WHO recommended maximum for cow milk. The other substances were found in fewer milk samples, however, in some of these samples they were found in relatively high amounts. In Norway, only DDT has been investigated earlier (4), and compared to that study, there has been no significant change in the mean concentration of DDT in human breast milk during the last five years. The insecticide content was highest in colostrum and decreased with increasing duration of lactation. Considerable fluctuations in the content of insecticides were recorded in repeated milk samples collected from the same woman a few days apart. The percentage of samples with insecticide content higher than that permitted for cow's milk was greater in May/June (79%) than in early April (54%). The significance of these findings is discussed.

Aldrin↗

PubMed1985

The eradication of Damalinia ovis by spraying insecticide onto the tip of the wool.

The eradication of lice from Merino sheep with wool up to 65 mm long was achieved by spraying insecticide onto the tip of wool over the sides and back. The insecticides used were cyhalothrin and diazinon in small volumes and at high concentration. When infested sheep were sprayed with 100 ml of cyhalothrin 1,500 ppm or diazinon 36,000 ppm, no live lice were seen 23 days after treatment. When treated sheep were challenged with live lice 100 days after treatment an infestation did not establish. Cyhalothrin at a lower concentration of 1,000 ppm gave excellent control but at 500 ppm only fair control was obtained. Diazinon at 24,000 ppm gave probable eradication and at 12,000 ppm excellent control. If a practical method of applying the insecticide to the tip of wool can be developed, then this technique should provide an effective means of eradicating lice in sheep with long wool. This would greatly assist the sheep industry in controlling and eradicating sheep lice.

Animals↗

PubMed1973

Synergism of insecticides by herbicides.

The herbicides atrazine, simazine, monuron, and 2,4-D (2,4-dichlorophenoxyacetic acid) enhanced the toxicity of selected insecticides to Drosophila melanogaster Meigen, Musca domestica L., and larvae of Aedes aegypti L. The insecticides-nine organophosphorus compounds, two chlorinated hydrocarbons, and one carbamate-were used at dosages that resulted in low insect mortalities, while the herbicides by themselves were nontoxic. Atrazine was most effective. With increasing amounts of this herbicide and constant amounts of some insecticides, increasing mortalities of fruit flies were observed. Exposure of the insects for 24 hours to carbofuran (0.5 microgram), p,p'-DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] (4 micrograms), parathion (0.35 microgram), and diazinon (0.2 microgram) alone resulted in mortalities of 7.5, 9.5, 8, and 10.5 percent, respectively. Based on dosage mortality curves obtained with increasing amounts of atrazine, mortalities of 50 percent of the insect populations would have been achieved with 23, 40, 6, and 10 micrograms of atrazine added to the abovementioned dosages of carbofuran, DDT, parathion, and diazinon, respectively.

2,4-Dichlorophenoxyacetic Acid↗

PubMed1979

Toxaphene, a complex mixture of polychloroterpenes and a major insecticide, is mutagenic.

Toxaphene, the most widely used chlorinated insecticide, is mutagenic in the Salmonella test without requiring liver homogenate for activity. This insecticide is a complex mixture (more than 177 polychloroterpenes) with carcinogenic activity in rodents. Some but not all of the mutagenic components are easily separated from the insecticidal ingredients.

Dose-Response Relationship, Drug↗

PubMed2006

Identification, typing, and insecticidal activity of Xenorhabdus isolates from entomopathogenic nematodes in United Kingdom soil and characterization of the xpt toxin loci.

Xenorhabdus strains from entomopathogenic nematodes isolated from United Kingdom soils by using the insect bait entrapment method were characterized by partial sequencing of the 16S rRNA gene, four housekeeping genes (asd, ompR, recA, and serC) and the flagellin gene (fliC). Most strains (191/197) were found to have genes with greatest similarity to those of Xenorhabdus bovienii, and the remaining six strains had genes most similar to those of Xenorhabdus nematophila. Generally, 16S rRNA sequences and the sequence types based on housekeeping genes were in agreement, with a few notable exceptions. Statistical analysis implied that recombination had occurred at the serC locus and that moderate amounts of interallele recombination had also taken place. Surprisingly, the fliC locus contained a highly variable central region, even though insects lack an adaptive immune response, which is thought to drive flagellar variation in pathogens of higher organisms. All the X. nematophila strains exhibited a consistent pattern of insecticidal activity, and all contained the insecticidal toxin genes xptA1A2B1C1, which were present on a pathogenicity island (PAI). The PAIs were similar among the X. nematophila strains, except for partial deletions of a peptide synthetase gene and the presence of insertion sequences. Comparison of the PAI locus with that of X. bovienii suggested that the PAI integrated into the genome first and then acquired the xpt genes. The independent mobility of xpt genes was further supported by the presence of xpt genes in X. bovienii strain I73 on a type 2 transposon structure and by the variable patterns of insecticidal activity in X. bovienii isolates, even among closely related strains.

Alleles↗

PubMed1981

Inhibition of aflatoxin production by selected insecticides.

The insecticide naled completed inhibition production of aflatoxins B1, B2, G1, and G2 by and growth of Aspergillus parasiticus at a 100-ppm (100 microgram/ml) concentration. The insecticides dichlorvos, Landrin, pyrethrum, Sevin, malathion, and Diazinon significantly (P = 0.05) inhibited production of aflatoxins at a 100-ppm concentration. However, at a concentration of 10 ppm, significant inhibition in production of aflatoxins was found only with naled, dichlorvos, Sevin, Landrin, and pyrethrum. Dichlorvos, Landrin, Sevin, and naled inhibited growth of A. parasiticus by 28.9 , 18.9, 15.7, and 100%, respectively, at 100 ppm. Stimulation of growth was observed when diazinon was added to cultures. Aflatoxin B1 was most resistant to inhibition by insecticides, followed by G1, G2, and B2, respectively.

Aflatoxins↗

PubMed1989

Expression of the insecticidal protein gene from Bacillus thuringiensis subsp. aizawai in Bacillus subtilis and in the thermophile Bacillus stearothermophilus by using the alpha-amylase promoter of the thermophile.

Expression of the insecticidal protein gene from Bacillus thuringiensis subsp. aizawai IPL7 in B. subtilis MI113 and B. stearothermophilus SIC1 was examined. Production of the protein (130 kilodaltons [KDa]) was analyzed by its reaction with antibody against the insecticidal proteins of the parental B. thuringiensis. When the original gene containing its own promoter was subcloned in B. subtilis, only a small amount of the protein was produced. Therefore, both the promoter for the B. stearothermophilus alpha-amylase gene and the insecticidal protein gene were inserted in a repA (low-copy-number) plasmid to yield the recombinant plasmid pTBT-Pamy. B. subtilis MI113 carrying pTBT-Pamy produced more of the 130-kDa protein (about 10(4) molecules per cell) at 37 degrees C. In contrast, B. stearothermophilus SIC1 carrying pTBT-Pamy produced a small amount of 130-kDa protein (10(2) to 10(3) molecules per cell) at 55 degrees C.

Amylases↗

PubMed1997

The Bacillus thuringiensis vegetative insecticidal protein Vip3A lyses midgut epithelium cells of susceptible insects.

The Vip3A protein is a member of a newly discovered class of vegetative insecticidal proteins with activity against a broad spectrum of lepidopteran insects. Histopathological observations indicate that Vip3A ingestion by susceptible insects such as the black cutworm (Agrotis ipsilon) and fall armyworm (Spodoptera frugiperda) causes gut paralysis at concentrations as low as 4 ng/cm2 of diet and complete lysis of gut epithelium cells resulting in larval death at concentrations above 40 ng/cm2. The European corn borer (Ostrinia nubilalis), a nonsusceptible insect, does not develop any pathology upon ingesting Vip3A. While proteolytic processing of the Vip3A protein by midgut fluids obtained from susceptible and nonsusceptible insects is comparable, in vivo immunolocalization studies show that Vip3a binding is restricted to gut cells of susceptible insects. Therefore, the insect host range for Vip3A seems to be determined by its ability to bind gut cells. These results indicate that midgut epithelium cells of susceptible insects are the primary target for the Vip3A insecticidal protein and that their subsequent lysis is the primary mechanism of lethality. Disruption of gut cells appears to be the strategy adopted by the most effective insecticidal proteins.

Animals↗

PubMed1972

Microbial metabolites with insecticidal properties.

A screen of fungi for insecticidal activity revealed the ability of Aspergillus versicolor to make versimide, methyl-alpha-(methylsuccinimido)acrylate, a novel contact insecticide. The larvicidal activities of Alternaria tenuis and Fusarium lateritium were found to be due to tenuazonic acid and diacetoxyscirpenol, respectively. Thiolutin, cycloheximide, rubratoxin, patulin, trichothecin, an actinomycin, and scirpene-producing fungi also had insecticidal activity.

Animals↗

PubMed1975

Inhibition of phenylamide hydrolysis by Bacillus sphaericus with methylcarbamate and organophosphorus insecticides.

The degradation of the phenylamide herbicides monolinuron, linuron, and solan by cultures of Bacillus sphaericus ATCC 12123 was inhibited by the methylcarbamate insecticides metmercapturon, aldicarb, propoxur, and carbaryl and by the organophosphorus insecticides fenthion and parathion. The extent of inhibition was largest with metmercapturon and smallest with parathion inhibition of hydrolysis of the two phenylurea herbicides was greater than of the acylanilide compound. Tests with crude enzyme preparations of aryl acylamidase derived from B. sphaericus showed that the inhibition of the hydrolysis of linuron with methylcarbamates is a competitive one. The insecticides tested did induce the enzyme, nor could they serve as its substrate.

Amidohydrolases↗

PubMed2002

Presentation and outcome of severe anticholinesterase insecticide poisoning.

AIMS: To document the patterns of presentation and outcome of severe anticholinesterase insecticide poisoning in children requiring intensive care. METHODS: Retrospective case note review of all 5541 children admitted to the paediatric intensive care unit (PICU) of a university hospital during the 10 years from January 1990 to May 2000. Fifty four children (1%) with anticholinesterase insecticide poisoning were identified. Presenting features, route of exposure, treatment, complications, and mortality were recorded. Data were analysed by the Fisher's exact and Mann-Whitney tests. RESULTS: More children than expected were from a rural area (46% versus 25%). Decontamination occurred in 50% of children prior to PICU admission. Enteral exposure was most common (n = 27; 50%). Median pseudocholinesterase level was 185 IU/l (range 75-7404). Median total dose of atropine required to maintain mydriasis was 0.3 mg/kg (range 0.03-16.7) over a median of 10 hours (range 1-160). Complications included coma (31%), seizures (30%), shock (9%), arrhythmias (9%), and respiratory failure requiring ventilation (35%). No significant differences were detected in incidence of seizures, cardiac arrhythmias, respiratory failure, mortality, duration of ventilation, or PICU stay, according to route of exposure, or state of decontamination. Four children died (7%). Mortality was associated with the presence of a cardiac arrhythmia (likelihood ratio 8.3) and respiratory failure (likelihood ratio 3.3). CONCLUSION: The mortality and morbidity of severe anticholinesterase insecticide poisoning in childhood is not related to route of exposure, or to delay in decontamination. However, the presence of either a cardiac arrhythmia or respiratory failure is associated with a poor prognosis.

Adolescent↗

PubMed2002

Insecticide impregnated curtains to control domestic transmission of cutaneous leishmaniasis in Venezuela: cluster randomised trial.

OBJECTIVE: To measure the impact on transmission of leishmaniasis of curtains impregnated with insecticide. DESIGN: Cluster randomised controlled trial: household interview survey, observational study of people's behaviour, entomological study with light trap captures of sandflies inside houses. SETTING: 14 urban sectors in Trujillo, Venezuela. PARTICIPANTS: 2913 inhabitants of 569 houses. INTERVENTION: Sectors were paired according to their 12 month cumulative incidence of cutaneous leishmaniasis, one sector in each pair was randomly allocated to receive polyester curtains impregnated with lambdacyhalothrin (intervention group) while the other sector received curtains without insecticide or no curtains (control groups). After 12 months a follow up household survey was conducted. MAIN OUTCOME MEASURES: Reduction in abundance of sandflies indoors and 12 month incidence of clinical cases of cutaneous leishmaniasis. RESULTS: Transmission of cutaneous leishmaniasis occurred mainly in the domestic setting, with the incidence over 12 months of 4%. The mean number of sandflies per trap per night was 16. After follow up the 12 month incidence of cutaneous leishmaniasis was 0% in the intervention group and 8% in the six pairs in the control group that received unimpregnated curtains (mean difference 8, 95% confidence interval 4.22 to 11.78; P=0.001). There were significantly fewer sandflies in the intervention group (2 v 15, mean difference 13 sandflies per trap; 9 to 17; P<0.001). CONCLUSION: Curtains impregnated with insecticide provide a high degree of protection against indoor transmission of cutaneous leishmaniasis.

Adolescent↗

PubMed2006

Effective control of dengue vectors with curtains and water container covers treated with insecticide in Mexico and Venezuela: cluster randomised trials.

OBJECTIVES: To measure the impact on the dengue vector population (Aedes aegypti) and disease transmission of window curtains and water container covers treated with insecticide. DESIGN: Cluster randomised controlled trial based on entomological surveys and, for Trujillo only, serological survey. In addition, each site had a non-randomised external control. SETTING: 18 urban sectors in Veracruz (Mexico) and 18 in Trujillo (Venezuela). PARTICIPANTS: 4743 inhabitants (1095 houses) in Veracruz and 5306 inhabitants (1122 houses) in Trujillo. INTERVENTION: Sectors were paired according to entomological indices, and one sector in each pair was randomly allocated to receive treatment. In Veracruz, the intervention comprised curtains treated with lambdacyhalothrin and water treatment with pyriproxyfen chips (an insect growth regulator). In Trujillo, the intervention comprised curtains treated with longlasting deltamethrin (PermaNet) plus water jar covers of the same material. Follow-up surveys were conducted at intervals, with the final survey after 12 months in Veracruz and nine months in Trujillo. MAIN OUTCOME MEASURES: Reduction in entomological indices, specifically the Breteau and house indices. RESULTS: In both study sites, indices at the end of the trial were significantly lower than those at baseline, though with no significant differences between control and intervention arms. The mean Breteau index dropped from 60% (intervention clusters) and 113% (control) to 7% (intervention) and 12% (control) in Veracruz and from 38% to 11% (intervention) and from 34% to 17% (control) in Trujillo. The pupae per person and container indices showed similar patterns. In contrast, in nearby communities not in the trial the entomological indices followed the rainfall pattern. The intervention reduced mosquito populations in neighbouring control clusters (spill-over effect); and houses closer to treated houses were less likely to have infestations than those further away. This created a community effect whereby mosquito numbers were reduced throughout the study site. The observed effects were probably associated with the use of materials treated with insecticide at both sites because in Veracruz, people did not accept and use the pyriproxyfen chips. CONCLUSION: Window curtains and domestic water container covers treated with insecticide can reduce densities of dengue vectors to low levels and potentially affect dengue transmission.

Aedes↗