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PubMedDate not supplied

[Studies of the sensitivity to the usual domestic insecticides on insects of the Anopheles maculipennis group, and Musca domestica, Cimex lectularius and Blattella germanica species].

The present paper was designed to the study of the degree of sensitivity of mosquitoes, flies, bedbugs and cockroaches to organochloride and organophosphoric insecticides produced in Romania. Testing of the sensitivity to insecticides of these species, important as transmitters of human pathogens, showed the effectiveness of the products, which induced a high mortality rate in relatively small concentrations. Against Anopheles labranchiae atroparvus, the insecticides Detox, Carbetox and Lindatox proved efficient in concentrations of 1.0%, 0.5% and 1.0% respectively. Against Musca domestica Lindatox and Detox proved efficient in 1.0% concentration. Cimex lectularius responded with a mortality rate of 100% to 0.5% Lindatox, 1.5% Plotox and 1.0% Dipterex. Against Blattela germanica, 100% mortality was obtained after one hour exposure to Lindatox, Detox and Carbetox in 1.0% concentration, to 3.3% Plotox and 1% Piretrin.

Animals↗
PubMedDate not supplied

[Current data on the biology and response to insecticides of Anopheles mosquitoes in former endemic zones of southern Romania].

In the 1976-1980 period biological and ecologic investigations were carried out on the Anopheles fauna in the former endemic malarial areas in the Danube plains and the Dobrogea. Due to the changes in the ecology of the region new aspects were observed among this fauna: 1) reduced anopheles density as compared to previous years; 2) change in the proportion of the Anopheles species; 3) resistance of the Anopheles to organochloride insecticides and sensitivity to organophosphoric and carbamate insecticides. The authors recommend the use of the Ficam W insecticide in doses of 0.3 g active substance per square meter for disinfestation against mosquitoes in houses.

Anopheles↗
PubMed1981

Studies on biting Simulium damnosum s.l. at a breeding site in the Onchocerciasis Control Programme area during and after an interruption of insecticidal treatments.

The increase of population of biting S. damnosum s.l. at a breeding site situated within the Onchocerciasis Control Programme area of West Africa following a temporary cessation of insecticidal treatments was studied by making every day collections on human bait at five catching sites and for 2--3 days per week at seven others, between 17 January and 9 April 1977. Observations on pupal and larval densities, water and air temperatures, relative humidity and water level were also made. The results showed that there was an interval of 23 days between the last application of insecticide and the appearance of the first nulliparous biting flies. This coincided with the finding of the first S. damnosum larvae. Subsequently, the biting densities increased following a geometric progression from about 10 flies per day to a maximum of 188 per day, giving a daily rate of increase of 1.07. Ten days after the re-application of insecticide, biting densities had fallen to about 5% of the pre-control level giving a daily rate of decrease of 0.74. Very little dispersion was observed with biting rates falling to 5% at 3000 m. perpendicular to the river. At these sites nullipars predominated. Conversely along the axis of the river densities at 1000 m away had to only 68% and were composed mainly of parous flies. Studies on diel activity showed the greatest biting activity between 15.00 h and 18.00 h with a lesser period of activity between 07.00 and 10.00 h. The significance of these observations in future planning of control strategy is discussed.

Animals↗
PubMed1980

Investigation of the safety of industrial strains of microorganisms and microbial insecticides.

Toxicology-hygienic studies of insecticidal preparations produced on the basis of fungi of the species Beauveria bassiana and bacteria of the species Bac. thuringiensis, recommended for use in plant-growing, were carried out. It has been established that the industrial strains of entomopathogenic microorganisms and insecticidal preparations produced on the basis of these microorganisms are harmless in the epidemiological sense and of low toxicity, but they may have a sensitizing effect on the human organism. On the grounds of results of toxicological experiments and hygienic observations in the field it has been concluded that prophylactic measures in the production and application of microbial insecticides should be aimed at restricting the contact of people with entomopathogenic microorganisms and preparations produced on their basis.

Animals↗
PubMed1993

[Resistance to the organophosphate insecticides temephos and malathion in Culex pipiens L. (Diptera, Culicidae) from the Adriatic coast near Friuli].

Susceptibility to organophosphorus insecticides Temephos and Malathion was tested in Culex pipiens L. larvae from Friuli Adriatic coast (North-East of Italy). The samples were collected in various sites of three zones with different intensity of insecticidal treatments. Tests were made following the W.H.O. recommendations. The tests were made on larval samples which were exposed for 24 hours to ascending concentrations of each insecticide. From the observed percentage mortalities the LC50 and LC90 values were calculated. The resistance ratio was obtained comparing the CL50 values with reference CL50 values provided by the W.H.O. The obtained data suggest the existence of Cx. pipiens populations resistant to the tested chemicals in the most intensively treated touristic zone (Lignano Sabbiadoro). The samples collected in an agricultural zone with no mosquito control treatments showed a slight reduced susceptibility to the tested compounds.

Animals↗
PubMedDate not supplied

Evaluation of susceptibility status of Culex quinquefasciatus larvae to few organophosphorus insecticides based on logistic regression analysis.

A laboratory trial was carried out at Pune to evaluate the effectiveness of five types of larvicides viz. Malathion, Temephos, Fenthion, Dichlorvos and Fenitrothion against Culex quinquesfasciatus larvae. The expected number of mortality at various dose levels for the five types of insecticides were estimated separately using logistic regression model. Based on the fitted model, the estimated dose level corresponding to the 90 percent mortality (LC90) was obtained for each insecticide. Approximate 95 percent confidence intervals for the LC90 dose, in each case, has been provided. The analysis revealed that out of all the five types of insecticides included in the study, fenthion was the most effective. The estimated value of LC90 in this case was the lowest and is equal to 0.007 mg/L. The effectiveness of temephos, dichlorvos and fenitrothion was found to be approximately same and malathion was the least effective. The results were found to be comparable with that obtained under probit method.

Animals↗
PubMedDate not supplied

A rapid multiresidue screen for organophosphorus, organochlorine, and N-methyl carbamate insecticides in plant and animal tissues.

A multiresidue screen for the quantitative determination of 43 organophosphorus, 17 organochlorine, and 11 N-methyl carbamate insecticides in 10 g of plant or animal tissues is described. The insecticides are extracted with 5% ethanol in ethyl acetate (v/v). Samples with high lipid content are cleaned up by automated gel permeation chromatography with a 30% ethyl acetate in hexane (v/v) eluant and in-line silica gel minicolumns. Highly pigmented samples are cleaned up with class-specific solid-phase extraction columns. The concentrated extracts are analyzed by selective detection with gas chromatography or liquid chromatography. Recovery of 71 insecticides ranged from 77 to 113%. Analysis of fortified bovine liver (n = 5) resulted in an average recovery of 96 +/- 4% at the 0.5 to 0.05 micrograms/g level. Analysis of fortified alfalfa hay (n = 5) resulted in a mean recovery of 94 +/- 4% at the 0.06 to 0.5 micrograms/g level, and analysis of fortified fresh tomatoes (n = 5) resulted in an average recovery of 97 +/- 3% at the 0.06 to 0.5 micrograms/g level. Method detection limits ranged from 0.02 to 0.5 micrograms/g for the compounds studied with a nominal 10 g sample.

Acetates↗
PubMed1993

[Studies on insecticidal ingredients from culture supernatant of Bacillus thuringiensis].

Studies on the insecticidal activity of culture supernatant of Bacillus thuringiensis var. kurstaki HD-1, by centrifugation, column chromatography, protein sequence determination, bioassay and other methods. Found that insecticidal activity of culture supernatant appeared on synchronism with cells lysis. Main insecticidal ingredients of culture supernatant is toxin protein of 60 kilodaltons (kDa). Analyse hat purified the toxin protein, we find that its amino acid composition was similar with 135-kDa P1 protein, and its sequence of N-terminal 18 amino acid was same with that of part of the P1 protein. The results presented here provided that the toxin protein was the same source with the P1 protein. Further found that supernatant have synergizing action on the sediment of culture.

Amino Acid Sequence↗
PubMedDate not supplied

Automated sample preparation for monitoring groundwater pollution by carbamate insecticides and their transformation products.

We investigated automated on-line solid-phase extraction (SPE) followed by liquid chromatographic (LC) techniques for monitoring carbamates and their transformation products. Analytical determinations were performed by LC with UV or postcolumn fluorescence detection (U.S. Environmental Protection Agency Method 531.1 for carbamate insecticides) after preconcentration with on-line SPE using C18 Empore extraction disks. On-line SPE/LC/thermospray mass spectrometry with time-scheduled selected-ion monitoring was used as confirmatory method. The method was used to determine pesticide traces in well waters of a typical aquifer in the Almeria area (Andalucia, south of Spain) from March 1993 to February 1994. The major pollutants, found in highest amounts, were carbofuran, methiocarb, and methomyl, at levels of 0.32, 0.3, and 0.8 micrograms/L, respectively. According to results of seasonal variation studies, pollution by carbamate insecticides is sporadic and exceeds the limit of 0.5 micrograms/L for total pesticides allowed by the European Economic Community Drinking Water Directive only twice a year. 3-Hydroxycarbofuran and methiocarb sulfone also were detected, showing the importance of including the main toxic break-down products of carbamate insecticides in future monitoring programs.

Autoanalysis↗
PubMedDate not supplied

Multiresidue liquid chromatographic method for simultaneous determination of pyrethroid insecticides in fruits and vegetables.

A simple and rapid liquid chromatographic (LC) method has been developed for simultaneous determination of 9 pyrethroid insecticides (biphenthrin, cypermethrin, fenpropathrin, fenvalerate, flucythrinate, methothrin, permethrin, py-115, and tetramethrin) in fruits and vegetables. Residues are extracted from crops with methanol and partitioned with toluene. Extracts are cleaned up by Florisil-charcoal column chromatography. LC separation is performed on a muBondapak C18 stainless steel column with acetonitrile-deionized water as mobile phase. The insecticides are detected at 206 nm with 0.03 absorbance unit full scale. Recoveries of 9 pyrethroid insecticides from 6 crops (cucumbers, tomatoes, cabbages, apples, pears, and peaches) fortified at 0.5-5.0 mg/kg were 62.7-129.2%. Detection limits were about 0.05 mg/kg, except for py-115, for which detection limit was 0.10 mg/kg.

Chromatography, Liquid↗
PubMed1996

Insecticide susceptibility status of some anophelines in district Bikaner, Rajasthan.

Insecticide susceptibility tests were conducted on the adults of four anopheline species namely. Anopheles annularis, An. culicifacies, An. stephensi and An. subpictus against the diagnostic doses of six insecticides, viz. DDT (4.0%), dieldrin (0.4%), malathion (5.0%). fenitrothion (1.0%), propoxur (0.1%) and permethrin (0.25%) in District Bikaner (Rajasthan). A time dependent effect has been observed with each insecticide. All the four species were found resistant to DDT and dieldrin and susceptible to fenitrothion and permethrin. An culicifacies and An. subpictus showed susceptibility to malathion, while further verification for the other two species was required. However, with propoxur An. annularis showed resistance, whereas for other three species further studies are required. DDT and dieldrin, the two organochlorines, were found least effective as compared to organophosphates and carbamates.

Animals↗
PubMed1996

Evaluation of cattle insecticide treatments on attraction, mortality, and fecundity of mosquitoes.

Attraction, engorgement, mortality, and fecundity were observed on host-seeking Aedes vexans and Psorophora confinnis given the opportunity to feed on insecticide-treated steers in stable traps. Individual steers were treated with Ectrin ear tags, Ectrin spray, Terminator ear tags, Saber ear tags, or Ivomec injection or were left untreated. Aedes vexans and Ps. confinnis accounted for over 98% of 20,738 mosquitoes collected. Relative attraction ranged from 0.45 with Saber ear tag to 0.84 with Terminator ear tag. Engorgement rates of mosquitoes from insecticide-treated steers ranged from 55 to 91%. Engorgement was reduced 18-45% by Terminator ear tag, Ectrin spray, and Saber ear tag treatments. Forty-eight percent mortality of unengorged Ae. vexans and 61% mortality of unengorged Ps. confinnis was observed at collection with the Saber ear tag treatment. Percentage of mortality of engorged mosquitoes of both species was generally much lower. Ivomec injection treatment showed the greatest effect on delayed (48-h) mortality of engorged mosquitoes, with 41 and 82% mortality for Ae. vexans and Ps. confinnis, respectively. No insecticide treatment had a significant effect on fecundity.

Aedes↗
PubMed1996

Systemic application of pyrethroid insecticides evokes differential expression of c-Fos and c-Jun proteins in rat brain.

Expression of the c-Fos and c-Jun transcription factor was investigated by immunocytochemistry in the thalamus, hypothalamus, hippocampus and cortex of adult rats following intraperitoneal application of proconvulsant doses of the pyrethroid insecticides, cypermethrin and permethrin. Pyrethroid insecticides are used world-wide and their uptake, e.g., by nutrition and inhalation evokes severe neurological symptoms in animals and humans, but their effects on neuronal gene expression has not been elucidated. Cypermethrin induced a strong expression of c-Fos and c-Jun in all the thalamic nuclei, except the ventro-posterior complex and substantia nigra, and in all the hypothalamic nuclei. In general, the immunoreactivities (IR) persisted for 8 h on their maximal levels, and were still above control levels after 24 h in several thalamic and hypothalamic areas. c-Fos-IR was strongly increased in all cortical layers with a predominance in the superficial layers II-IV, whereas c-Jun-IR was only slightly increased. In the hippocampus, cypermethrin induced a weak expression of c-Fos, but not of c-Jun, in the dentate gyrus and CA-3 area. Permethrin that has a lower pharmacological potency, evoked a similar pattern of c-Fos and c-Jun expression, however, intensity and persistence of the neuronal labeling were less pronounced. Our results demonstrate that the neurotoxic effects of pyrethroid insecticides comprise molecular genetic alterations in the brain such as early and lasting induction of Fos and Jun transcription factor proteins. These changes in the neuronal program are prominent in the hypothalamus and thalamus that are involved in the regulation of the autonomic and visceral nervous systems.

Animals↗
PubMed1996

Bee head acetylcholinesterase as an indicator of exposure to organophosphate and carbamate insecticides.

Insect acetylcholinesterase has received special attention following the discovery that inhibition of the enzyme is the mechanism of activity of the organophosphate and carbamate insecticides. Apiculture is an important source of Greek income and as the detection of anticholinesterase insecticides in bees is very difficult, investigation of the cause of death of honeybees due to acetylcholinesterase inhibition is of great value and will contribute to the differential diagnosis of bee diseases. The enzymatic assay is not capable of distinguishing between individual pesticides', but is an indicator of the exposure of bees to anticholinesterase insecticides.

Animals↗
PubMed1997

Assessment of the ability of propoxur, methomyl, and aldicarb, three carbamate insecticides, to induce micronuclei in vitro in cultured Chinese hamster ovary cells and in vivo in BALB/c mice.

Three carbamate insecticides (propoxur, methomyl, and aldicarb) were evaluated for their ability to induce micronuclei (MN) in vitro using cultured Chinese hamster ovary (CHO) cells, and in vivo in mouse bone marrow erythrocytes. In vitro, all three insecticides induced a significant increase in micronucleated binucleate cells, which was generally both dose and sample time dependent. The in vivo studies involved treating male BALB/c mice by different routes, either once or on 3 consecutive days, followed by multiple or single sampling. Treatment by intraperitoneal injection or oral gavage induced a significant increase in micronucleated reticulocytes (MNRETs) in peripheral blood. For all three chemicals, the MN response depended on sample time and the number of treatments, while for aldicarb, the response depended also on the route of exposure. These positive results demonstrate that propoxur, methomyl, and aldicarb are capable of inducing structural and/or numerical chromosomal aberrations in mammalian cells either in vitro or in vivo. Furthermore, based on the results obtained, on optimal in vivo MN protocol for carbamate insecticides is a single treatment followed by blood sampling at 24 and 48 hr after treatment.

Aldicarb↗
PubMed1997

Cell culture models of interspecies selectivity to organophosphorous insecticides.

In toxicology, the need to reduce uncertainties in human risk assessment is met by understanding why species and individuals within that species respond differently to chemical exposure. This kind of information is needed when extrapolating data from experimental (i.e., whole animal) systems to the human condition in terms of risk assessment. In 1993 the Neurotoxicology Division of the Environmental Protection Agency funded several investigators to examine this phenomenon (i.e., interspecies selectivity) using cell culture models. Organophosphorous (OP) insecticides were examined since they are characterized by an extremely divergent interspecies response. In 1995, a symposium entitled Novel Insights into Chemical Neurotoxicity, sponsored by the Society for In Vitro Biology featured this research. In it, a historical overview of the phenomenon of interspecies selectivity to OP insecticides was given, current explanations for it were discussed and contemporary in vitro models being used to explain it, were described. Data from these studies have helped to redefine the underlying mechanisms that characterize and influence the cross-species response to insecticides. These experiments have refocused the explanation of this phenomenon to include cellular metabolism, target enzyme baseline activities, and receptor-mediated electrophysiological and second-messenger events. Several investigators on this panel also reported on the use of subcellular markers (e.g., target esterases, second messengers, ionic fluxes) to differentiate neuropathy-causing OP compounds from acetylcholinesterase inhibitors. After these presentations, technical considerations used in the designed of in vitro neurotoxicity studies were discussed.

Animals↗
PubMed1997

Acceptability and use of insecticide impregnated bednets in northern Ghana.

A district-wide study was undertaken in a rural population of northern Ghana to identify factors influencing the acceptance and use of insecticide-impregnated bednets (IIBNs). A series of focus group discussions were conducted during 2 years of implementation of IIBNs to gauge community reactions to the introduction of the nets and a structured questionnaire was administered to approximately 2000 randomly selected individuals. Although the IIBNs were accepted and used because they provided protection from mosquito bites, seasonal factors, patterns of use, and questions of cost were key factors likely to influence the dissemination and effectiveness of bednets. Use of the bednets was highly seasonal. Almost all recipients used their IIBNs in the rainy season (99%), corresponding to the period of high mosquito density and 20% used them in the dry seasons, the period of low mosquito density. Mothers with young children were more likely to wash the bednets frequently (because the children soiled the bednets with faeces and urine), resulting in no protection from the insecticide. Provision of wider bednets, or the provision of plastic sheets with the bednets or possible incorporation of the insecticide in washing soaps could improve protection for young children. The success of the promotion of IIBNs in malaria control programmes will depend on the cost of the package and the time of year that it is delivered. Financing mechanisms for individual and village groups are discussed. Social research effectively monitored the intervention in this study, and it should be included as an important component of national malaria control programmes.

Adult↗
PubMed1997

New treatment regimens in organophosphate (diazinon) and carbamate (methomyl) insecticide-induced toxicosis in fowl.

The objective of this work was to determine optimal treatment regimens for organophosphate (OP) or carbamate insecticide toxicoses in fowl using the antidotes atropine sulfate and pralidoxime chloride (2-PAM). Broiler chicks in treatment groups, each comprising 3 replicates of 6-7 birds/replicate, were gavaged on a body weight (BW) basis with the OP and carbamate insecticides, diazinon and methomyl, respectively, at lethal dosages. Treatment groups were injected with either or both of the antidotes at various dosages as soon as clinical signs appeared. Birds appearing healthy 24 h thereafter were regarded as having been treated successfully. At a dosage of 100 mg/kg BW, atropine was mildly toxic and at 200 mg/kg 2-PAM was severely toxic (but not lethal), whereas at dosages of 50 and 100 mg/kg BW, respectively, the antidotes were at their most effective. With diazinon, atropine alone was only partially effective (12/20 survivors), whereas 2-PAM was extremely efficacious. (20/20 survivors); the combination of the 2 antidotes at 2 dosages was slightly less effective (19/20 survivors) than 2-PAM alone. For methomyl toxicity, atropine was largely successful (18/20 survivors), whereas 2-PAM was mostly unsuccessful (10/20 survivors); the combination at high dosage was less effective (15/20 survivors) than atropine alone, but at a low dosage the combination was the most successful (20/20 survivors). The results indicate that anticholinesterase insecticide toxicoses in fowl should not be treated according to textbook recommendations, and antidotal dosage with atropine should be up to 100 times greater than is commonly recommended. The specific cause of the toxicoses should ideally be determined before treatment is given, but as this is often unknown, a combination of antidotes may be the optimal treatment protocol.

Animals↗