Management of pyrethroid exposure

Differences in Knowledge, Awareness, Practice, and Health Symptoms in Farmers Who Applied Organophosphates and Pyrethroids on Farms

OBJECTIVE

This cross-sectional study aimed to examine farmers' knowledge, awareness, practices regarding pesticide use, and prevalence of health symptoms related to pesticides exposure among farmers who applied organophosphates (OP) and pyrethroids (PY).

METHODS

Data regarding demographic variables and health symptoms pertinent to pesticide use was collected from 67 farmers who applied OP and 50 farmers who applied PY using interviews from January to March 2021.

RESULTS

The farmers who applied OP had lower knowledge, awareness, and prevention practices regarding pesticide use than those who applied PY. After adjustment of covariate variables, the farmers who applied OP had a significantly higher prevalence of respiratory conditions (OR = 8.29 for chest pain, OR = 6.98 for chest tightness, OR = 27.54 for dry throat, and OR = 5.91 for cough), neurological symptoms (OR = 10.62 for fatigue and OR = 6.76 for paresthesia), and neurobehavioral symptoms (OR = 13.84 for poor concentration, OR = 3.75 for short term memory, and OR = 8.99 for insomnia) related to pesticide exposure than those who applied PY.

CONCLUSION

Our findings suggest that OP had a more adverse effect on human health than PY, resulting in a higher prevalence of pesticide-related symptoms. The outcomes of this study have the benefit of providing vital information for all stakeholders with regard to the implementation of safe practices in the utilization of personal protective equipment (PPE) and pesticide use in a health intervention and health promotion program.

A Case of Pyrethroid Poisoning with Clinical Presentation Mimicking Organophosphate Poisoning

We report an 89-year-old retired farmer with prolonged bradycardia and hypotension after pyrethroid insecticides ingestion in a suicidal attempt. This patient also had a clinical manifestation mimicking organophosphate poisoning, included confusion, lacrimation and salivation. He required intensive care support, atropine and inotrope infusions treatments. Only metabolites of synthetic pyrethroid insecticides (3-phenoxybenzoic acid and 3-phenoxybenzaldehyde) were detected in the urine sample. In the serum toxicology screening, specific analysis for organophosphate pesticides was negative. He eventually recovered without major sequela. (Hong Kong j.emerg.med. 2016;23:47-51)

Chemical Necrotising Fasciitis Secondary to Self-Injection of Permethrin Insecticide

We report a 65-year-old male with chemical necrotising fasciitis after self-injection of permethrin insecticide. The patient also developed persistent hypoglycemia secondary to massive insulin overdose. There was no evidence of systemic toxicities from the insecticide poisoning. Multiple debridement and skin grafting were performed over his right forearm due to extensive tissue damage. He eventually recovered with impairment of his right hand function. The clinical features and the management of this uncommon route of insecticide poisoning are discussed. (Hong Kong j.emerg.med. 2011;18:441-445)

Validation of a Rapid and Sensitive UPLC-MS-MS Method Coupled with Protein Precipitation for the Simultaneous Determination of Seven Pyrethroids in 100 µL of Rat Plasma by Using Ammonium Adduct as Precursor Ion

United States Environmental Protection Agency has recommended estimating pyrethroids' risk using cumulative exposure. For cumulative risk assessment, it would be useful to have a bioanalytical method for quantification of one or several pyrethroids simultaneously in a small sample volume to support toxicokinetic studies. Therefore, in the present study, a simple, sensitive and high-throughput ultraperformance liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous analysis of seven pyrethroids (fenvalerate, fenpropathrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, cypermethrin and deltamethrin) in 100 µL of rat plasma. A simple single-step protein precipitation method was used for the extraction of target compounds. The total chromatographic run time of the method was 5 min. The chromatographic system used a Supelco C18 column and isocratic elution with a mobile phase consisting of methanol and 5 mM ammonium formate in the ratio of 90 : 10 (v/v). Mass spectrometer (API 4000) was operated in multiple reaction monitoring positive-ion mode using the electrospray ionization technique. The calibration curves were linear in the range of 7.8-2,000 ng/mL with correlation coefficients of ≥ 0.99. All validation parameters such as precision, accuracy, recovery, matrix effect and stability met the acceptance criteria according to the regulatory guidelines. The method was successfully applied to the toxicokinetic study of cypermethrin in rats. To the best of our knowledge, this is the first LC-MS-MS method for the simultaneous analysis of pyrethroids in rat plasma. This validated method with minimal modification can also be utilized for forensic and clinical toxicological applications due to its simplicity, sensitivity and rapidity.

Histomorphometric study of testis in deltamethrin treated albino rats

Deltamethrin, a type II synthetic pyrethroid, has lead to a widespread concern over the potential adverse effects on human health. Adult Wistar albino rats, weighing 150-200 g, were divided into two groups of ten animals each. The group II rats were injected with deltamethrin (1 mg/kg body weight) intraperitoneally, for five days/week for a month. The group I were controls. Animals were sacrificed within 24 h of the last injection by perfusion under anesthesia. Paraffin sections (8 μm) were cut, and stained with hematoxylin and eosin. Histomorphometry was done. There was a decrease in the body weight but increase in the weight of the testis of rat. The mean vertical, antero-posterior and transverse diameter of the testis is reduced. The basement membrane enclosing the seminiferous tubules appeared thickened at sites. The number of seminiferous tubules per unit area is statistically significantly reduced. There was a generalized significant decrease in the diameter and the epithelium thickness (height) of the seminiferous tubules, associated collapse and distortion at sites of the tubules predominantly in the central region. The data obtained in the present work suggest that gonadal (testis) changes could seriously affect the reproductive potential of the rat.

Identification and characterization of two phospholipid hydroperoxide glutathione peroxidase genes from Apis cerana cerana

Phospholipid hydroperoxide glutathione peroxidase (PHGPX) plays a crucial role in maintaining the integrity of membrane by reducing hydroperoxides of phospholipids. Here, we report the identification and characterization of two genes, designated AccGtpx-1 and AccGtpx-2, encoding PHGPX proteins from the Chinese honeybees, Apis cerana cerana. Alignment analysis showed that AccGtpx-1 and AccGtpx-2 shared high similarity with other known PHGPXs, which show similar structure to thioredoxin. These single copy genes showed complex exon-intron structures. The mRNA of AccGtpx-1 was detected in larvae, pupae and adults and that AccGtpx-2 was only found in adult worker bees. Furthermore, the expression of AccGtpx-1 could be induced by H(2)O(2), ultraviolet (UV) light, heat shock (37 degrees C), HgCl(2), imidacloprid, cyhalothrin, pyriproxyfen and methomyl. In contrast, AccGtpx-2 expression could only be induced by UV. These results indicated for the first time that the AccGtpx-1 and AccGtpx-2 genes encoding A. cerana cerana PHGPXs are regulated differently in response to environmental stressors.

Prallethrin induced biochemical changes in erythrocyte membrane and red cell osmotic haemolysis in human volunteers

Changes in biochemical composition in erythrocyte membrane, erythrocytic osmotic haemolysis, and nitrite and nitrate levels in plasma were analyzed in 12 human volunteers who were exposed regularly to prallethrin, a type I pyrethroid mosquito repellent. The results revealed a decrease in cholesterol (C) and phospholipid (P) moieties in erythrocyte membrane with no consequent change in C:P ratio. Further, a significant decrease in the content of phosphatidyl serine suggested that PS is a sensitive phospholipid species to the pyrethroid action. Significant decrease in membrane lipid peroxidation and enhanced levels of nitrite and nitrate in plasma and erythrocyte indicate that increased generation and availability of nitric oxide might have rendered tolerance to erythrocyte membrane by protecting the cells from haemolysis. Increased NO(2) and NO(3) may be due to increased activity of nitric oxide synthase (NOS) and/or expression of isoforms of NOS. A possible involvement of free radical scavenging and antioxidant effects of nitric oxide might have contributed to the observed decrease in lipid peroxidation in the present study.

The synaptosomal membrane bound ATPase as a target for the neurotoxic effects of pyrethroids, permethrin and cypermethrin

Pyrethroids are used widely as insecticides both in agriculture and in households. A cellular target of pyrethroids is the sodium channel in the membrane. In the present study, the activity of the membrane bound integral protein ATPase was studied as a biomarker for the membrane effect of the pyrethroids permethrin and cypermethrin. Male Sprague-Dawley rats were used for cerebral synaptosome preparation. The isolation of synaptosomes was performed with the Percoll gradient method. Both total ATPase and Mg(2+) activated ATPase were studied by determining inorganic phosphate liberated from the substrate ATP. One hour exposure to permethrin (Biokill) and cypermethrin (Ripcord) insecticide products affected ATPase activities. The activity of Na(+), K(+) ATPase decreased dose-dependently in 10-50 microM concentrations of permethrin, and Mg(2+) activated ATPase increased over twofold in the same concentrations of the active components. The effect of the cypermethrin compound Ripcord was not clearly dose-dependent. The activity of total ATPase was almost entirely lost in the concentrations of 100 microM of permethrin and cypermethrin. The results support the idea that membrane ATPases are one target of the neurotoxic effect of pyrethroid compounds.