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The effect of organophosphorus insecticide, valexon, has been investigated on hydrobionts from different taxonomic groups. Survival, locomotor activity, oxygen consumption and free radical spectra were determined. High sensitivity to the effect of the insecticide was found in Daphnia, due to the specific action of it on locomotor and respiratory functions, which are closely related in crustaceans.
The usefulness was tested of the biological insecticides containing B. thuringiensis available in the market in the eradication of cockroaches. Thuridan was the most effective out of the tested insecticides in reducing the number of the insects. Its higher activity in relation to Thuricide was evident at all tested concentrations. Males were more sensitive than females. On the other hand, no significant response of cockroaches to M-one preparation was noted, since the per cent of dying insects was only slightly higher than in the control group.
Rat metabolism studies were conducted with three organophosphorus ester insecticides: [phenyl- or ethoxy-14C]Dyfonate, O-ethyl S-phenyl ethylphosphonodithioate; [phenyl-14C]Trithion, S-[(4-chlorophenylthio)methyl]O,O-diethylphosphorodithioate; and [phenyl-14C]R-14805, 4-[O,0-diethyl phosphorothioyl)]-acetophenoneoxime-N'-methylcarbamate. Compounds were administered orally to rats at 2 to 8 mg/kg, and biotransformation pathways were established from identified metabolites. Metabolites were isolated from O-96 hr urine and identified by using one or more methods including thin-layer chromatography, radio-gas-liquid chromatography, mass spectrometry, and nuclear magnetic resonance. Each of these model insecticides displayed a distinct bioactivation and detoxification pathway. Conversion to potent acetylcholinesterase inhibitors resulted from desulfuration of Dyfonate, desulfuration and thioether oxidation of Trithion, and desulfuration and a variety of modifications of the leaving group of R-14805. The compounds were deactivated primarily via cleavage of an organophosphorus ester group. All three compounds and their metabolites were rapidly excreted primarily in urine without any bioaccumulation in tissues.
North Bohemia is recognized to be one of the most polluted areas in Europe. Combustion processes in several power plants, other industrial activities, transportation, waste incineration and household furnaces belong to the main sources of the air pollution. Therefore, the presence of numerous organic pollutants, namely polycyclic aromates (PAHs), chlorinated insecticides and polychlorinated biphenyls (PCBs) is expected to contribute significantly to the impaired health conditions. Samples of the ambient air collected in different seasons were analysed using GC-ECD, GC-MS and HPLC methods. Chlorinated insecticides and PCBs have been found of minor importance with concentrations laying below 0.1 ng/m3 and 1.0 ng/m3 respectively. Among PAHs, phenanthrene, fluoranthene and pyrene have been the major components. Concentrations of PAHs found during heating period have been about 10 times higher than those observed in the late spring. The role of household furnaces and motor vehicles in production of compounds is discussed.
A high insecticidal activity of K-otrin (flow), a preparation containing 2.5% of deltametrin, towards various arthropods, was revealed in laboratory experiments and in field trials. The effective doses were determined: 0.01-0.1 g/m2. Residual effects of the insecticide on the treated surfaces persist for 3 months and longer. Toxicologic studies revealed the possibility of using K-otrin for medical disinfection. The preparation is permitted for use by the Ministry of Health.
Anopheles koliensis, an important malaria vector in the interior region of Irian Jaya, Indonesia, was evaluated for susceptibility to three different insecticide compounds using the standard World Health Organization diagnostic test kit and pretreated impregnated papers. A series of tests were conducted in Arso PIR I, a transmigrant settlement 60 km south of Jayapura, from January 1988 to May 1989. All compounds were tested at the recommended diagnostic dosage and exposure time. An. koliensis were susceptible to 1.0% fenitrothion at two hour exposure (N = 358) and 5.0% malathion at one hour exposure (N = 371) after the 24-hour holding period. Significant resistance to DDT was observed in both the An. koliensis and Culex quinquefasciatus populations. Approximately 30% of the An. koliensis population (N = 468) was resistant to 4% DDT at both one and two hour exposures. These findings indicate that routine use of DDT in Arso PIR I for indoor residual house spraying may be of limited effectiveness, in part, because of physiological resistance. However, use of an alternative insecticide will be more expensive and might prove equally ineffective because of the exophilic behavior of the species. This is the first confirmed report from repeated observations of DDT resistance in An. koliensis from Indonesia.
A 61-year-old female was admitted to our hospital because of cough, hemosputum and right chest pain. The P-A and L-R chest films revealed focal consolidation in the right upper filed and mass-like shadow in the right S3. Transbronchial lung biopsy specimens showed collections of lipid-laden macrophages. The lipid material of macrophages in broncholaveolar lavage fluid was stained yellow-orange with Sudan IV. The patient had no difficulty in swallowing and had no history of regular use of oily drugs. Fiberoptic bronchoscopy and chest CT showed no obstruction of bronchi. She had used much domestic insecticide with the doors closed before going to bed every summer and autumn for 10 years. We concluded that the domestic insecticide containing mineral oil had resulted in exogenous lipoid pneumonia. Her symptoms and abnormal shadows in chest X-ray film disappeared soon after antimicrobial chemotherapy was started. She is now healthy without recurrence.
A comparative insecticide village-scale trial was carried out to determine the efficacy of low-volume (LV) indoor spray of bendiocarb, deltamethrin and cyfluthrin for the control of Anopheles albimanus in a coastal plain of southern Mexico. Low-volume spray was conducted with knapsack mist-blowers, giving an average discharge rate of 215 ml/min, which deposited droplets of 50-100 microns. Using this technique, 25 houses were treated/sprayman/day as compared with 8 houses/sprayman/day using conventional hand compression pumps. Indicators of LV mortality showed a residual activity of 10 wk as compared with 13 wk of activity for wettable powder (WP) (bendiocarb). When comparing expenditures, LV spray costs were 43% less when using bendiocarb, 83% less with deltamethrin and 74% less with cyfluthrin with respect to the conventional WP spray of the same insecticides. Low-volume spray time was reduced by one-third, with respect to WP. Malaria incidence was reduced by 53 and 56%, respectively, in the bendiocarb LV and deltamethrin LV treated villages as compared with the untreated village.
A comparative regional-scale evaluation of the epidemiological impact of low volume (LV) spray of bendiocarb and the conventional spray of DDT against malaria in an endemic area of northern Chiapas was carried out. Three Anopheline species were found: Anopheles pseudopunctipennis, An. albinanus and An. argyritarsis. The most prevalent was An. pseudopunctipennis, a species we suspect may be involved in the transmission of most malaria cases. This species showed high levels of resistance to DDT. However, this insecticide had a long residual effect in wall bioassays, with mortalities > or = 95 per cent for up to 21 weeks in wood, sticks and plaster. Susceptibility to bendiocarb was total, and mortality to LV bendiocarb was > or = 75 per cent for up to 16 weeks in wood, sticks and straw. Very low numbers of mosquitoes were found throughout the evaluation, although malaria transmission continued in control villages (sprayed with DDT), as well as treated villages (sprayed with LV bendiocarb). No plasmodium infected mosquitoes were found, perhaps due to a very small sample size. The LV spray methodology was found to be 1.7 times more effective than conventional spraying in reducing malaria incidence. A net reduction of 1.6 times in insecticide application time was also found, which would allow spraying at the right time, especially when urgent control measures have to be applied, such as in malaria outbreaks. Finally, the new methodology costs 2.2 times more than the conventional ddt spraying, but if the potential of using spray workers in other activities is considered, costs would be comparable to those of DDT spraying.
Organophosphate toxicity can be fatal. It accounts for almost 40 percent of all insecticide- and pesticide-related illnesses reported by the American Association of Poison Control Centers. Skin contamination is the most important route of occupational exposure. Carbamate insecticides exhibit a similar mechanism of acute toxicity. Organophosphate pesticides act as irreversible acetylcholinesterase inhibitors, while carbamate pesticides produce reversible effects. The inhibition of acetylcholinesterase causes accumulation of acetylcholine at nerve endings, resulting in a cholinergic or hypersecretory syndrome. Persons who are exposed to organophosphates must be admitted to the hospital for careful observation. Symptoms should be treated with atropine, and most patients should also receive pralidoxime, a cholinesterase-regenerating drug.
Allethrin is a widely used pyrethroid insecticide with an alkenylmethylcyclopentenolone group in its structure. We have analyzed its interaction with model and native membranes using DPH and its polar derivative TMA-DPH fluorescence polarization. Allethrin modified the bilayer order in the temperature range of the phase transition when incorporated into liposomes made with dimyristoyl-(DMPC), dipalmitoyl-(DPPC) and distearoyl-(DSPC) phosphatidylcholine. In DMPC: allethrin mixtures the pyrethroid decreased the bilayer order in the gel phase, without altering the liquid-crystalline one. In native membranes, DPH and TMA-DPH fluorescence polarization remained unchanged after incubation with allethrin. The release of hemoglobin was notably facilitated by the incorporation of allethrin into human erythrocytes. The results are discussed in terms of a possible aggregation of the insecticide in the lipid bilayer to create special domains with a consequent increase in membrane instability.
Spontaneous motor activity (SMA), conditioned avoidance response (CAR), muscle coordination (MC) and pentobarbital sleep were tested in rats treated orally for 90 days with tolerated doses of the cyclodiene insecticides, aldrin (1 mg/kg) and endosulfan (2 mg/kg). The same tests were repeated in similarly treated animals after injecting chlorpromazine (4 mg/kg, i.p.). Both the insecticides shortened pentobarbital sleeping time indicating their microsomal enzyme inducing property. Aldrin suppressed SMA, CAR and MC, whereas endosulfan stimulated SMA, inhibited CAR and unaltered MC. However, their concurrent action with CPZ did not result in change in the central depressive effects of the latter, but its potency during the course of its action was altered. Its potency 15 min after injection was greater and 60-180 min later was lesser in these animals than that observed in control animals. This finding was interpreted to suggest that aldrin and endosulfan has quickened the biotransformation of CPZ and thereby shortened its duration of action. A temporary promotion of its potency was accounted to its active metabolites, since prior to inactivation, CPZ is known to be metabolized by the microsomal enzymes to active compounds.
The dispersion of testing results is due not only to an error in the representative choice of specimens for an experiment, but also to the specific features of each specific experiment. In defining the confidence interval of the value of insecticidal activity it should not be oriented to data on variability of individual tests rather than to the error in the dose-mortality regression representativeness. The test permits one to establish differences in the insecticidal activity of the agents which differ in this index at least by 1.5-fold.
The effect of the organophosphorus insecticide methylparathion and its main metabolite methylparaoxon on chloride and sulfate equilibrium exchange in pig erythrocytes was investigated using an isotope labelling technique. Efflux of both radioactive isotopes with time followed a single exponential. Methylparathion and methylparaoxon inhibited the chloride equilibrium exchange in erythrocyte ghosts in a dose- and time-dependent manner. There was no difference between effects evoked by these two compounds. Methylparathion and methylparaoxon inhibited sulfate efflux from resealed ghosts. The effect was also dose- and time-dependent. Again, there was no difference between the action of both agents. Dixon analysis revealed a non-competitive character of the inhibition of the exchange of both anions with apparent Ki values 183 and 184 microM for methylparathion and methylparaoxon, respectively in the case of chloride transport; for sulfate exchange these values were 675 and 648 microM. It was suggested that structural similarity between the parent agent and its metabolite accounts for their identical effects. Methylparathion and methylparaoxon might inhibit the anion exchange indirectly by changing the fluidity of the erythrocyte membrane or directly by binding to the band 3 protein and evoking conformational changes that lead to the inhibition of the anion transport. The insecticides, due to their ability to phosphorylate, might also disturb some regulation processes in the band 3 protein and affect anion transport in this way.
The effect of supermethrin on the overall health with respect to weight gains, diet intake, triad values (body temperature, pulse rate and breathing rate) and potential intoxication signs was investigated in sheep of the Slovak Mertino breed (age of 8 months, males and females) during 6-week feeding of the insecticide supermethrin (Research Institute of Chemical Technology, Bratislava). This insecticide supermethrin contains a cyanide group in its molecule and can be included in the group of type II pyrethroids. It is an analog of cypermethrin and it has a different proportion of cis- and trans-isomers. Supermethrin mixed with molasses feed M was administered daily at a dose of 50 mg/kg (about 1/70 of LD50) to five sheep of experimental group I, at a dose of 200 mg/kg (about 1/15 of LD50) to five sheep of experimental group II, and the dose increased from 200 mg to 300 mg/kg l.w. (about 1/20 of LD50) since the fourth week of trial. The main signs of its toxic action involved depressive effects on weight gains (Fig. 4) Over the whole period of trial, the live weight rose by 5.44 +/- 1.94 kg in control group, by 2.66 +/- 1.48 kg in experimental group I, which equates a significant decrease by 51.10% and only 0.34 +/- 0.95 kg in experimental group II, which equates a decrease in weight gains by up to 93.75% against the control. We do not believe that the growth depression can be related to diet intake. There were no larger differences in feed intake between the experimental groups and the control. The growth depression was caused by incessant diarrhea. The patho-morphological examination did not reveal hyperemia and/or intestinal inflammation, the histological examination did not show any lesions of epithelium in the intestinal mucosa. An increase in supermethrin dose from 200 to 300 mg/kg l.w. resulted in signs coming from the CNS. Hypersensibility manifested by moderate unrest, head and neck shaking after auditory, and especially after touch stimuli was observed. This tremor was increasing to became spontaneous 3-4 days before trial termination. The above findings clearly suggest that supermethrin administration at lower doses has harmful effects primarily on the digestive tract, but at higher doses these effects are more intensive accompanied by the effects on the CNS. No negative effects on pulse rate (Fig. 1), breathing rate (Fig. 2) and internal body temperature (Fig. 3) were recorded.
Permethrin is an active ingredient found in many public hygiene insecticide products and exposure to it was assessed in a survey of 45 professional users. The exposures measured were over a wide range, with more than a 100-fold difference between average levels and the highest levels. Dermal contamination was evident on 93% of the operators, the highest contamination resulting from the use of leaking application equipment, demonstrating that proper maintenance of equipment is vital. Where the insecticide was applied at ground level most contamination was on the legs, indicating the importance of appropriate footwear. Contamination of the hands occurred despite the use of protective gloves, higher levels of contamination occurring when liquids were used. Dermal contamination was not always the principle route of exposure, and high airborne concentrations were linked with use in confined areas. Airborne concentrations were also associated with the physical form of the product used and the treatment method. To help in assessing the effectiveness of protective clothing and control measures, biological monitoring was carried out. Monitoring of metabolites in urine showed that systemic uptake occurred but evidence from toxicological studies indicates that the levels found were well below those considered to cause harm.
Poisonings due to organophosphate insecticides are a common accident with serious consequences in Vietnam. In this report we describe a case due to ingestion of carbamate by a 4 years old boy. Muscarinic and nicotinic manifestations appeared within 90 minutes after ingestion. In addition to evacuation of the stomach and oxygenotherapy, treatment consisted of high dose atropine: 1,396 capsules in 18 days (349 mg). The authors review the mechanisms of poisoning which leads to accumulation of acetylcholine in nerve endings and emphasize the need for preventive measures in developing countries where use of this type of insecticide is widespread.
Toxicity of six larvicides ie fenthion, temephos, malathion, deltamethrin, alphamethrin (Fendona), OMS 3031 and five adulticides ie malathion, fenitrothion, propoxur, deltamethrin, permethrin to Aedes aegypti, Culex quiquefasciatus, Anopheles stephensi and the predator, Toxorhynchites splendens was studied for evaluating safety margin. Concentrations of alphamethrin that killed 50% larvae of T. splendens were 53 and 12 times more than that which killed Cx. quinquefasciatus and Ae. aegypti. In case of deltamethrin, concentrations required to kill 50% larvae of T. splendens were 14 and 5 times more than that required against other two species. Other larvicides tested were equally toxic to both T. splendens and vector mosquitos. There was no significant difference in the toxicity of larvicides to T. splendens and An. stephensi. Deltamethrin was 25-132 times less toxic to adults of T. splendens in comparison to vector mosquitos. For other adulticides the range was 1-10. Immature developmental time of T. splendens was not affected by any of the insecticides tested. However, predation rate was lowered when larvae of Ae. aegypti previously exposed to fenthion and temephos were offered. Whereas, alphamethrin and OMS 3031 did not affect the feeding rate of the predator. There was a significant reduction in the pupal weight and pupation as a result of the predator feeding on the insecticide treated prey. There was a significant negative relationship between rate of pupation and dosage. The present study indicates that synthetic pyrethroids owing to their higher safety margin can be used in an integrated vector management program.