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PubMedDate not supplied

[Potentiation of deltamethrin toxicity by organophosphorus insecticides].

There is a potential hazard in mixed intoxications by pyrethroids and organophosphate insecticides, due to the fact that low toxicity of pyrethroids on mammals is chiefly due to quick cleavage of molecule by esterases, which can be thwarted by esterase inhibitors. We have developed a method in order to measure the duration and the intensity of potentiation of deltamethrin by a variety of organophosphate compounds. It was demonstrated that some of them (azinphos, dichlorvos, dimethoate, fenitrothion, omethoate) induce an increase of toxicity of deltamethrin. But, the total toxicity of association of Deltamethrin with Dimethoate, Fenitrothion, is weak, and does not prohibit their use. Others (methyl-parathion, acephate, phosphamidon, monocrotophos) have no such effects, even if they have a very high intrinsic toxicity. Cholinesterase inhibitors of the carbamate group are ineffective. It is suggested that the potentiation is mainly in relation with the kinetic of esterase inhibition, which is different, and specific to each organophosphate compound. So, it is essential that a specific toxicological measurement must be performed with any different insecticide, in order to anticipate the danger of a mixed intoxication by pyrethroids and organophosphates.

Animals↗
PubMedDate not supplied

[Insecticidal activity of pyrethroids for houseflies and German cockroaches].

Insecticidal and knock-down effects of eight pyrethroids, belonging to 2 types as to their chemical structure and specific action towards the nervous system, on the domestic flies' and German cockroaches' imago were assessed comparatively. Pyrethroids of the 2nd type, especially deltametrine, proved to be more effective against domestic flies as well as German cockroaches. Activity of the pyrethroids of the 1st type featured rapid knock-down effect and was practically independent from varying concentrations. The knock-down was reversible even at high concentrations. In case of the 2nd type of pyrethroids, the knock-down effect was concentration-dependent. Domestic flies, on the whole, were more sensitive to the effect of pyrethroids of the 1st type. The use of pyrethroids of the 2nd type against nonflying sinathropic insects would be advisable because they produce a higher insecticidal effect as well as irreversible knock-down.

Animals↗
PubMed1989

Effects of sublethal dosages of insecticides on Culex quinquefasciatus.

Groups of Culex quinquefasciatus were exposed as fourth instar larvae to sublethal concentrations (0.1 LC50 and LC50) of malathion, methoprene, propoxur or resmethrin. Females exposed as larvae to an LC50 level of methoprene had reduced wing length and longevity. Egg production was reduced by 50% and 39% in those mosquitoes exposed to LC50 levels of malathion or methoprene, respectively. In contrast, egg production and egg raft size increased following treatment with 0.1 LC50 levels of malathion or methoprene. Females exposed as larvae to methoprene laid 30% fewer eggs per raft, and egg hatching decreased 36% compared with controls. Females exposed as larvae to LC50 levels of malathion or methoprene laid shorter eggs than controls. The proportion of females in the adult population was reduced following exposure to either propoxur or resmethrin, and increased following exposure to malathion. Time to pupation and time of emergence of the adult populations were increased following exposure to most of the insecticidal treatments. These results indicated that a single, sublethal exposure to certain insecticides had a significant effect on mosquito reproduction.

Animals↗
PubMed1989

[Study on inhibiting effect of 14 insecticides on esterase of Culex tritaeniorhynchus from five geographic populations].

Isoelectrofocusing technique was used to study the inhibiting effect of 14 insecticides on esterase isozymes of Culex tritaeniorhynchus from natural populations in Fuzhou, Shanghai, Qingdao, Dalian and Beijing areas. Among 14 insecticides, organophosphates were good inhibitors to all esterase isozymes, but Allethrin, Propoxur, DDT, Dieldrin had no or almost no inhibiting effect on esterase. 26 esterase isozyme bands of Culex tritaeniorhynchus were revealed by isoelectrofocusing.

Animals↗
PubMedDate not supplied

[Cytomorphologic changes in bronchial epithelial cells in a patient exposed to an aerosol of the organophosphorus insecticide, Ekalux 25 (quinalphos), 0,0-diethyl-0-quinoxaline-2-phosphorothioate].

In this paper, the authors present cytomorphological changes of the bronchial epithelial cells in the patient who inhaled aerosol organophosphate insecticide "Ekalux 25" 0,0-diethyl-0-quinoxaline-2-il-phosphorothioate, while spraying crops, i.e. Colorado beetle. Our cytomorphologic examination of the sputum (obtained on the 13th and 15th day after the patient's exposure to the insecticide) revealed neutrophil granulocytes, degenerate changed macrophages, degenerate changed bronchial epithelial cells, squamous metaplasia with a poor number of lymphocytes and erythrocytes. Beside this, we also found atypical hypertropic cells of the bronchial epithelium (occurring in single forms or in groups) most of which appeared to be without cilia. Cytoplasm of those cells occurred to be not sharply bordered but poor and had a grey blue colour. Chromatin pattern of the nuclei was more coarse or "wiped", while nucleoli, as rule, appeared to be not discernible. There also occurred some nuclei in mitosis. The number of nuclei in those cells varies from one to several. Sputum specimens obtained later for cytologic analysis as well as bronchoscopic specimens, obtained on the 17th day after the patient's admission to the hospital, did not show any similar cytomorphologic changes. The authors of this paper think that it would be interesting to examine and follow-up the cytomorphologic specimens (bronchial secret, catheter bronchial aspirate smears, brushing and histopathologically) as early as the first days (if it is possible) of a patient's exposure to the organophosphate compounds.

Adult↗
PubMed1988

[Antagonistic and insecticidal properties of soil micromycetes].

It was shown that microscopic fungi isolated in plague foci had an antagonistic effect on the plague causative agent. In the majority of the cases it was associated with their insecticidal activity against plague-transmitting fleas. It is expedient to consider the relations revealed between the burrow biocenosis components in investigation of plague enzootic aspects and development of new biological insecticides for control of the infection carriers.

Animals↗
PubMed1988

[The mutagenicity of organic microcontaminants in the environment. I. The mutagenicity of selected herbicides and insecticides in the Salmonella microsome test (Ames test) with regard to the pathogenic potency of contaminated ground and drinking water].

For determination of the mutagenicity of herbicides and insecticides in working and environmental relevant concentrations we examined 26 pure substances of the chemical groups of polychlorinated alicyclic hydrocarbons, phenoxy fatty acids and and triazines with the Salmonella-microsome-test (S. typhimurium strains TA 97, TA 98, TA 100 and TA 102 with and without metabolic activation with Aroclor 1254 induced rat liver microsome fraction). Only one substance--Chlorthiamide--showed mutagenicity in concentrations of 0.001 microgram/plate. In all the other substances examined we found numbers of revertants near the spontaneous mutagenic rates. However a human carcinogenic potential can't be excluded, because several toxicological studies with mammalians showed a carcinogenic activity of organohalogenic insecticides without mutagenic activity in biological short term tests.

Animals↗
PubMed1988

Comparative effects of synthetic insecticides--endosulfan, phosalone and permethrin--on Chlamydomonas reinhardtii algal cells.

Presence of insecticide-endosulfan, phosalone or permethrin in the growth medium caused concentration dependent inhibition in the vegetative growth of Chlamydomonas reinhardtii algal cells. The rate of inhibition produced by endosulfan was two-fold higher than that of phosalone or permethrin. Endosulfan affected the cell growth completely at 100 times less concentration as compared to that of phosalone or permethrin. Non-dividing cell populations encountered significant losses in cells during their exposure (2 h) to endosulfan and did not show further loss in the 72 h post-treatment period. The populations treated with phosalone exhibited losses of considerable magnitude in the post-treatment period. Permethrin treated non-diving cell populations did not lower the cell number, either after the treatment period (2 h) or the post-treatment period (72 h). However, these populations showed reduced levels of chlorophyll following the exposure of the insecticide and did not display recovery or further reduction in the levels in the post-treatment period. The chlorophyll levels of endosulfan or phosalone treated cell populations remained unaffected. The cells remaining intact after the treatment (2 h) of endosulfan or phosalone exhibited significant decreases in their post treatment vegetative growth abilities. The growth ability of such permethrin exposed cells was similar to that of untreated cells.

Cell Count↗
PubMed1988

Acute pancreatitis after cutaneous exposure to an organophosphate insecticide.

Pancreatitis secondary to organophosphate insecticide toxicity is extremely rare. The few previously reported cases have resulted from oral ingestion of these agents. We present the first reported case of acute pancreatitis occurring after cutaneous exposure to an organophosphate insecticide. Symptoms of pancreatitis persisted for 6 months, followed by total resolution. The proposed mechanisms of pancreatic injury caused by organophosphate compounds are discussed.

Acute Disease↗
PubMedDate not supplied

Residues of insecticides, fungicides, and herbicides on Ontario-grown vegetables, 1980-1985.

Between 1980 and 1985, 354 composite vegetable samples representing 9 vegetable commodities were collected from farm deliveries to the market place in Ontario, Canada. All samples were analyzed for insecticides, 275 for fungicides, and 135 for herbicides. The analyses included organochlorine, organophosphorus, synthetic pyrethroid, and N-methylcarbamate insecticides; dithiocarbamate, acylalanine, phthalimide, dicarboximide, and other fungicides; and, chlorophenoxy acid, chlorobenzoic acid, bipyridilium, phenylurea, carbamate, and other herbicides. The commodities tested included asparagus, beans, carrots, cauliflower, cucumbers, onions, potatoes, sweet corn, and tomatoes. In most samples, pesticide residues were below the detection limits (i.e., 0.005 to 0.1 mg/kg), and most of the positive findings were a fraction (i.e., less than 1 to 20%) of the maximum residue limit (MRL) permitted for each commodity under the Canadian Food and Drugs Act and Regulations. A small number of samples had residues that exceeded the MRL, and these involved aldicarb and linuron on potatoes and chlorobromuron on carrots.

Fungicides, Industrial↗
PubMed1987

Carbamate poisoning: the 'other' insecticide.

A 16-month-old child who ingested rat poison, according to her parents, was noted to have signs of cholinergic poisoning. In the emergency department, the child was intubated and given atropine via the endotracheal tube until venous access was established. Phytonadione (vitamin K) and pralidoxime (2-PAM) were also administered. The child recovered after an uneventful hospital course. The toxic agent was determined to be a carbamate insecticide, for which treatment with pralidoxime is considered controversial. Treatment of cholinergic poisoning due to unknown or mixed agents and poisoning caused by known carbamate insecticides are discussed.

Antidotes↗
PubMedDate not supplied

[Cytogenetic activity of various organophosphorus insecticides].

The action of certain insecticides belonging to the group of organophosphorous compounds (chlorophos, metaphos, etaphos, phosphamid, phosalone, carbophos, selecron) has been studied by the test of chromosome aberrations in Crepis capillaris cells. It is shown that these insecticides possess mutagenic activity in all phases of the cell cycle and are mutagens of the undelayed action.

Chromosome Aberrations↗
PubMed1985

Safety measures associated with the use of organophosphate insecticides in the Haitian malaria control programme.

A programme emphasizing intensive training, use of protective equipment and uniforms, daily supervision of safety measures at work, and weekly monitoring of blood cholinesterase levels by the tintometric method was instituted to prevent toxicity in Haitian malaria workers during spraying with the organophosphate insecticides fenitrothion and malathion. The programme functioned well, depressed cholinesterase activity (</= 50% of normal) being detected rapidly prior to the development of serious symptoms. Evidence of fenitrothion overexposure appeared in spraymen early in the first spray cycle, and was associated with faulty protective clothing and a failure to observe strictly the recommended safety measures at work. After these deficiencies were corrected, insecticide application continued without serious incidents or interruption of the programme. No serious reduction of cholinesterase activity was seen in a more limited study of spraymen using malathion. It is strongly recommended that similar training and monitoring programmes should be instituted whenever organophosphate pesticides are used as residual sprays for malaria control. This is particularly important in areas where the more toxic compound, fenitrothion, is to be used.

Cholinesterases↗
PubMed1985

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

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

Animals↗
PubMed1970

Evaluation of compounds for insecticidal activity on adult mosquitos. 2. Toxicity to adult mosquitos and the physical properties of some new carbamates.

The N,N-dimethylcarbamates are much less toxic and much more volatile than the corresponding N-methylcarbamates. N-acylation of N-methylcarbamates is also generally accompanied by a loss in intrinsic toxicity to adult mosquitos by topical application, but the reduction in toxicity may be relatively small and in some N-acetyl derivatives may not occur at all. N-acylation is also accompanied by changes in physical properties such as lipid solubility and partition coefficient, which influence contact toxicity, and volatility, which affects residual activity. In the series of compounds examined, contact toxicity is maximal in the N-acetyl derivatives but their volatility is often so high that they lack the persistence required of residual insecticides. This does not apply, however, to the N-acetyl derivatives of OMS-597 and OMS-708 because the volatility of the parent compound is so low that some degree of persistence can be sacrificed to obtain some improvement in contact activity.OMS-1064 is the only N-chloroacetyl derivative tested so far that shows promise as a residual insecticide.

Animals↗
PubMed1965

A village-scale trial with the insecticides carbaryl and folithion in Southern Nigeria.

The insecticides carbaryl and Folithion were tested on a village scale in the vicinity of Lagos, Nigeria, by the WHO Insecticide Testing Unit in 1963. Whereas carbaryl reduced the density of anophelines and culicines for two months, Folithion greatly reduced their density for six months or more. The mortality among mosquitos leaving treated dwellings and caught in window-traps in the carbaryl-treated village was fairly high for only one month after treatment, but in the Folithion-treated village it was high for seven months. Bio-assay results showed that Folithion was effective on mud for two-and-a-half months, on wood for seven months, and on thatch for six months. Carbaryl was not effective on mud; on wood it was effective for nine months or more, and on thatch for six to nine months.Anopheles hargreavesi was found to be more exophilic than Anopheles gambiae or culicines.

Insecticides↗
PubMed1966

Development of resistance to various insecticides in Culex pipiens fatigans Wiedemann.

Since larvicidal treatment to reduce the numbers of Culex fatigans, the tropical house mosquito, offers a promising means of preventing the spread of filariasis, an assessment was made of the liability of C. fatigans to develop resistance to certain important insecticides. Strains of this mosquito from Burma, Cameroon, Sierra Leone and the USA (California) were submitted to larval selection for periods of seven to 23 generations. It was found that resistance to DDT or deutero-DDT rapidly developed to high levels and that to dieldrin or CP-47412 to moderate levels; dieldrin did not select for DDT-resistance.The organophosphorus compounds chosen developed only a modest tolerance-fivefold to sixfold with malathion or parathion, twofold to fourfold with fenthion or diazinon; the carbamate insecticide Hercules 5727 induced a threefold to fivefold tolerance. There was a general cross-tolerance from the selecting agent to all of the organophosphorus compounds tested and to the carbamate. A Rangoon strain that had already been made DDT-resistant subsequently developed a ninefold resistance to fenthion after 23 generations of selection with this organophosphorus compound, but this is still insufficient to annual the larvicidal effectiveness of fenthion.

Animals↗
PubMed1969

Ortho-isopropoxphenyl methylcarbamate (OMS-33) as a residual spray for control of anopheline mosquitos. With special reference to its evaluation in the WHO programme for evaluating and testing new insecticides.

More than 1300 compounds have so far been included in the WHO Programme for Evaluating and Testing New Insecticides, which is designed to disclose compounds that may satisfactorily replace those to which insect vectors of disease have become resistant. The authors describe the successful passage of o-isopropoxyphenyl methylcarbamate (OMS-33) through the first 6 stages of the 7-stage programme that has been established for compounds intended for use against anopheline mosquitos and conclude that this product is suitable for testing in the final stage-large-scale epidemiological evaluation.In operational field trials (at 2 g/m(2)) OMS-33 has been shown capable of controlling Anopheles stephensi (in Iran), An. gambiae and An. funestus (in Nigeria) for 3-4 months, An. albimanus (in El Salvador) for 2-4 months and An. dthali (in Iran) for 2(1/2) months. It has an airborne effect by which anophelines are killed for a considerable time after OMS-33 has been sprayed, even though they do not make contact with a sprayed surface; this quality would appear advantageous in areas where anophelines enter houses and bite man but do not rest long enough on sprayed surfaces to acquire a lethal dose of insecticide or where significant outdoor biting occurs. The observance of simple safety precautions protects occupants of sprayed houses, spraymen and others from danger. Chemical studies have indicated that commercially produced water-dispersible powders of OMS-33 are stable under field conditions of storage and use.

Aerosols↗