How many premature deaths from pesticide suicide have occurred since the agricultural Green Revolution?

Chlorpyrifos intermittent exposure enhances cardiovascular but not behavioural responses to contextual fear conditioning in adult rats: Possible involvement of brain oxidative-nitrosative stress

Exposure to organophosphorus compounds (OPs) may cause psychiatric, neurologic, biochemical, and cardiovascular abnormalities. Neurotoxicity of OP compounds is primarily due to irreversibly inhibition of the acetylcholinesterase (AChE) enzyme both centrally and peripherally. Chlorpyrifos (CPF) is a widely used OP classified as moderately toxic. Previously, it has been shown that CPF administration, given every other day to adult rats, impairs spatial memory and prepulse inhibition associated with brain AChE inhibition. Our group also found that intermittent treatment with CPF, simulating occupational exposure, impairs the cardiorespiratory reflexes and causes cardiac hypertrophy. Thereby, we aimed to examine whether subchronic and intermittent administration of CPF would affect the behavioural (freezing) and cardiovascular (mean arterial pressure, MAP; heart rate, HR) responses elicited during contextual fear conditioning (CFC) and extinction. Wistar adult male rats were injected with sublethal and intermittent CPF doses (4 and 7 mg/kg) three times a week for one month. Two days after the last injection, a range of tests were performed to assess depression (sucrose preference), anxiety (elevated plus-maze, EPM), locomotion (open field, OF), and conditioned fear expression and extinction. Separate cohorts of animals were euthanized to measure plasma butyrylcholinesterase (BChE), erythrocyte AChE, brain AChE activity, and markers of oxidative-nitrosative stress. Intermittent CPF treatment did not affect sucrose preference. CPF (4 and 7 mg/kg) reduced open-arms exploration in the EPM, suggesting an anxiogenic effect. The higher dose of CPF decreased the total distance travelled in the OFT, suggesting motor impairment. After a seven-day CPF-free washout period, CPF (7 mg/kg) increased the tachycardic response without affecting freezing behaviour in the CFC extinction session. CPF 7 mg/kg decreased AChE activity in the hippocampus, pre-frontal cortex and brainstem 72 after the last administration whilst transiently increasing oxidative-nitrosative stress specifically in the brainstem. Overall, our results outlined the behavioural, autonomic and biochemical abnormalities caused by an intermittent dosing regimen of CPF that elicits brain AChE inhibition and brain oxidative-nitrosative stress. This paradigm might be valuable in further exploring long-term consequences and mechanisms of OP neurotoxicity as well as comprehensive therapeutic approaches.

The relationships of plasma profenofos and ethanol concentrations to clinical outcome in acute profenofos self-poisoning

INTRODUCTION

Many patients acutely self-poisoned with organophosphorus insecticides have co-ingested ethanol. Currently, profenofos 50% emulsifiable concentrate (EC50) is commonly ingested for self-harm in Sri Lanka. Clinical experience suggests that ethanol co-ingestion makes management more difficult. Therefore, we aimed to determine the relationships between plasma ethanol concentration, plasma profenofos concentration and its toxicokinetics, and clinical outcome in acute profenofos self-poisoning.

METHODS

Demographic and clinical data, including a history of ethanol ingestion and blood samples, were prospectively collected from all cases of acute poisoning with profenofos EC50 presenting to Teaching Hospital Peradeniya, Sri Lanka, over four years. Plasma samples were analyzed by gas chromatography-mass spectrometry to quantify the ethanol (n = 99) and profenofos (n = 30 [15 with ethanol, 15 without ethanol]) concentrations. The PKSolver program was used to calculate the toxicokinetic parameters.

RESULTS

Of 99 patients (male 78/99) with acute profenofos self-poisoning, 50 reported a history of ethanol co-ingestion. Plasma from 44 of 99 profenofos-poisoned patients had detectable ethanol concentrations. No statistical difference was observed between the mortality in the ethanol group and the no ethanol group (5/44 [11.4%] versus 3/55 [5.5%]; P = 0.461). Similarly, the median half-lives of plasma profenofos absorption in the ethanol and no ethanol groups (0.1 h and 0.1 h, respectively; time 0-24 h) were not statistically different (P = 0.6594). However, the median half-life of plasma profenofos elimination was significantly longer in the ethanol group than the no ethanol group (23.1 h and 9.9 h, respectively; time 0-24 h; P = 0.0002). According to the regression analysis, the half-life of plasma profenofos elimination was longer by 29.4 h in the ethanol group (P = 0.013).

DISCUSSION

No significant differences in outcomes, including death and endotracheal intubation rates, were found between those who did and did not co-ingest ethanol. No differences were found in toxicokinetic variables between the ethanol and no ethanol groups, but the ethanol group had a longer elimination half-life.

CONCLUSION

The co-ingestion of ethanol leads to a slowing of the elimination kinetics of profenofos. However, the study did not reveal a significant impact of ethanol co-ingestion on clinical outcomes.

Ecotoxicological bioassays with terrestrial plants: a holistic view of standards, guidelines, and protocols

Terrestrial and aquatic ecosystems face various chemicals that might induce acute and/or long-term harm. To assess these impacts, ecotoxicological bioassays are essential. However, bioassays using animals, particularly mammals, are costly, time-consuming, and raise ethical concerns. In this context, terrestrial plants emerge as a viable alternative to conventional assays. Thus, the aim of this review was to address the history and evolution of plant bioassays, highlighting the main regulations, guidelines, and protocols governing the use of terrestrial plants in ecotoxicological tests. Initially, plant bioassays were employed to assess the cytogenotoxic effects of chemicals, gaining prominence with the GENE-TOX program in the 80s. Subsequently, plants were used in allelopathy bioassays and in studies aimed to examine the ecotoxicity of pesticides in soil. Currently, ecotoxicological bioassays with plants are regulated by specific standards, such as ASTM E1963-22, EPA 600/3-88/029, EPS 1/RM/45, ISO 11269-1, ISO 11269-2, ISO 17126, ISO 18763, ISO 29200, ISO 22030, OECD-208, OECD-227, OCSPP 850.4100, OCSPP 850.4230, OCSPP 850.4800 and OPPTS 850.4200. The existing protocols standardize bioassays in greenhouse and lab environments, and the duration of the tests varies from hours to months. The main ecotoxicological parameters to be analyzed after exposure include germination percentage, survival rate, root length, aerial part length, fresh mass of exposed plants, and phytotoxicity symptoms. In addition, the absorption rate of substances and genotoxic and mutagenic effects might also be assessed. Therefore, data in this review demonstrate that terrestrial plants represent an important tool in the analysis of environmental risks associated with chemicals and might serve as crucial allies in modern ecotoxicology.

Association between a large change between the minimum and maximum monthly values of solar insolation and a history of suicide attempts in bipolar I disorder

BACKGROUND

The rate of suicide attempts by patients with bipolar disorder is high. In addition to patient and country specific factors, environmental factors may contribute to suicidal behavior. Sunlight has multiple diverse impacts on human physiology and behavior. Solar insolation is defined as the electromagnetic energy from the sun striking a surface area on earth. We previously found that a large change in solar insolation between the minimum and maximum monthly values was associated with an increased risk of suicide attempts in patients with bipolar I disorder.

METHODS

The association between solar insolation and a history of suicide attempts in bipolar disorder was again investigated using an international database with 15% more data and more sites at diverse locations and countries.

RESULTS

Data were available from 5641 patients with bipolar I disorder living at a wide range of latitudes in 41 countries in both hemispheres. A large change in solar insolation between the minimum and maximum monthly values was associated with a history of suicide attempts in patients with bipolar I disorder, a replication of our prior analysis. The estimated model also associated state sponsored religion in the onset country, female gender, a history of alcohol or substance abuse, and being part of a younger birth cohort with a history of suicide attempts.

CONCLUSIONS

A large change between the minimum and maximum monthly values of solar insolation was associated with a history of suicide attempts in bipolar I disorder, replicating our prior research. Physicians should be aware that daylight has wide ranging physiological and psychiatric impacts, and that living with large changes in solar insolation may be associated with an increased suicide risk.

Prediction of chemical-induced acute toxicity using in vitro assay data and chemical structure

Exposure to various chemicals found in the environment and in the context of drug development can cause acute toxicity. To provide an alternative to in vivo animal toxicity testing, the U.S. Tox21 consortium developed in vitro assays to test a library of approximately 10,000 drugs and environmental chemicals (Tox21 10K compound library) in a quantitative high-throughput screening (qHTS) approach. In this study, we assessed the utility of Tox21 assay data in comparison with chemical structure information in predicting acute systemic toxicity. Prediction models were developed using four machine learning algorithms, namely Random Forest, Naïve Bayes, eXtreme Gradient Boosting, and Support Vector Machine, and their performance was assessed using the area under the receiver operating characteristic curve (AUC-ROC). The chemical structure-based models as well as the Tox21 assay data demonstrated good predictive power for acute toxicity, achieving AUC-ROC values ranging from 0.83 to 0.93 and 0.73 to 0.79, respectively. We applied the models to predict the acute toxicity potential of the compounds in the Tox21 10K compound library, most of which were found to be non-toxic. In addition, we identified the Tox21 assays that contributed the most to acute toxicity prediction, such as acetylcholinesterase (AChE) inhibition and p53 induction. Chemical features including organophosphates and carbamates were also identified to be significantly associated with acute toxicity. In conclusion, this study underscores the utility of in vitro assay data in predicting acute toxicity.

Features of fatal pesticide ingestion in South Australia

Pesticides are used to kill, repel or control any animal or plant species which are considered pests, but have also been associated with intentional and unintentional human fatalities. A rapid increase in pesticide suicides was observed during 'The Green Revolution' after pesticides were introduced into low- and middle-income rural households without appropriate guidelines for safe use and storage. While national pesticide bans have contributed to a significant decrease in pesticide-related suicides, such cases still comprise a large proportion of all suicides around the world. The aim of the current study was to provide a profile of pesticide suicides in a high-income country as a point of comparison against studies from low- and middle-income countries. Statistical analyses were performed using R (version 4.2.3). Over the 20-year study period, there were a low, yet consistent number of pesticide suicides which were most common among males over the age of 40. Paraquat and methomyl pesticides collectively contributed to almost half (48.8%) of all fatalities. Consistent with the literature, such cases often occurred with little premeditation in response to an acute emotional crisis. While interpretation of autopsy findings was mostly limited, there were some pesticides that demonstrated findings consisted with previously reported characteristics (e.g., gastroesophageal erosions with paraquat). Given the high proportion of cases where paraquat and methomyl pesticides were implicated, it may be appropriate to review the availability and accessibility of such compounds to reduce the occurrence of pesticide suicides in South Australia and potentially the wider Australian population.

Innovative disposable in-tip cellulose paper (DICP) device for facile determination of pesticides in postmortem blood samples: A proof-of-concept study

Accurately identifying and quantifying toxicants is crucial for medico-legal investigations in forensic toxicology; however, low analyte concentrations and the complex samples matrix make this work difficult. Therefore, a simplified sample preparation procedure is crucial to streamline the analysis to minimize sample handling errors, reduce cost and improve the overall efficiency of analysis of toxicants. To address these challenges, an innovative disposable in-tip cellulose paper (DICP) device has been developed for the extraction of three pesticides viz. Chlorpyrifos, Quinalphos and Carbofuran from postmortem blood samples. The DICP device leverages cellulose paper strips housed within a pipette tip to streamline the extraction process, significantly reducing solvent usage, time, and labor while maintaining high analytical accuracy. The extraction of pesticides from postmortem blood using the DICP device involves a streamlined process characterized by adsorption and desorption. The diluted blood samples were processed through the DICP device via repeated aspirating and dispensing calyces to adsorb the pesticides onto the cellulose paper. The adsorbed pesticides are then eluted using acetone, which is collected for GC-MS analysis. The method was meticulously optimized, achieving a limit of quantification in the range of 0.009-0.01 µg mL-1. The intra-day and inter-day precisions were consistently less than 5 % and 10 %, respectively, with accuracy ranging from 94-106 %. Relative recoveries for the analytes were observed to be between 60 % and 93.3 %, and matrix effects were determined to be less than 10 %. The method's sustainability was validated with a whiteness score of 98.8, an AGREE score of 0.64, a BAGI score of 70 and ComplexMoGAPI score of 77. Applicability was demonstrated through successful analysis of real postmortem blood samples and proficiency testing samples, highlighting its potential utility in forensic toxicology.

Application of the theory of planned behavior to model the intention and behavior of tomato growers in pesticide exposure

Widespread and indiscriminate use of pesticides has become one of the most important environmental and public health problems around the world. This study was conducted with the aim of applying the theory of planned behavior model to investigate the knowledge, attitude, and behavior of tomato growers in the face of pesticides in agricultural lands located in Kurdistan province, western Iran. We included 300 tomato growers in this study and they filled up a standard TPB questionnaire containing questions about basic information, knowledge, attitude and behavior about pesticides and their actions for disposing of the residual spray solution, washing place of pesticide sprayer, and the disposal of water from washing the equipment. Most of the respondents, 86.7 %, had not participated in promotional classes on how to dispose of the residual solution. Approximately 46.15, 38.46, and 15.39 % of pesticides contained moderately toxic, slightly toxic and practically non-toxic compounds, respectively. More than two-thirds (89 %) of the tomato growers stated that they leave the water from washing the equipment in the field. In addition, among the three variables of TPB, attitudes had the highest score (3.38), which indicated the positive to relatively neutral attitude of farmers towards the safe use of pesticides. These findings can be useful for planners and environmental organizations to make effective interventions to reduce environmental pollution caused by pesticides. Since the incorrect use of pesticides is one of the important environmental and health factors, education and awareness programs can help farmers to consider the correct use of pesticides and environmental protection more.

Restrictions on Pesticides and Deliberate Self-Poisoning in Sri Lanka

Importance

Deliberate self-poisoning using pesticides as a means of suicide is an important public health problem in low- and middle-income countries. Three highly toxic pesticides-dimethoate, fenthion, and paraquat-were removed from the market in Sri Lanka between 2008 and 2011. In 2015, less toxic pesticides (chlorpyrifos, glyphosate, carbofuran, and carbaryl) were restricted. Subsequent outcomes have not been well described.

Objective

To explore the association of pesticide bans with pesticide self-poisonings and in-hospital deaths.

Design, Setting, and Participants

In this cross-sectional study with an interrupted time series design, data were prospectively collected on all patients with deliberate self-poisonings presenting to 10 Sri Lankan hospitals between March 31, 2002, and December 31, 2019, and analyzed by aggregated types of poisoning. The correlates of pesticide bans were estimated within the pesticide group and on self-poisonings within other substance groups. The data analysis was performed between April 1, 2002, and December 31, 2019.

Exposures

Implementation of 2 sets of pesticide bans.

Main Outcomes and Measures

The main outcomes were changes in hospital presentations and in-hospital deaths related to pesticide self-poisoning as measured using segmented Poisson regression.

Results

A total of 79 780 patients (median [IQR] age, 24 [18-34] years; 50.1% male) with self-poisoning from all causes were admitted to the study hospitals, with 29 389 poisonings (36.8%) due to pesticides. A total of 2859 patients died, 2084 (72.9%) of whom had ingested a pesticide. The first restrictions that targeted acutely toxic, highly hazardous pesticides were associated with an abrupt and sustained decline of the proportion of poisonings with pesticides (rate ratio [RR], 0.85; 95% CI, 0.78-0.92) over the study period and increases in poisonings with medications (RR, 1.11; 95% CI, 1.02-1.21) and household and industrial chemicals (RR, 1.20; 95% CI, 1.05-1.36). The overall case fatality of pesticides significantly decreased (RR, 0.33; 95% CI, 0.26-0.42) following the implementation of the 2008 to 2011 restrictions of highly hazardous pesticides. Following the 2015 restrictions of low-toxicity pesticides, hospitalizations were unchanged, and the number of deaths increased (RR, 1.98; 95% CI, 1.39-2.83).

Conclusions and Relevance

These findings support the restriction of acutely toxic pesticides in resource-poor countries to help reduce hospitalization for and deaths from deliberate self-poisonings and caution against arbitrary bans of less toxic pesticides while more toxic pesticides remain available.

Carbamate compounds induced toxic effects by affecting Nrf2 signaling pathways

Carbamate (CBs) is a class of insecticides which is being known as an important cause of intentional or accidental poisoning. CBs, cause carbamylation of acetylcholinesterase at neuronal synapses and neuromuscular junction. Exposure to CBs through skin contact, inhalation, or ingestion can result in significant cholinergic toxicity. This is due to the elevation of acetylcholine levels at ganglionic synapses found in both the sympathetic and parasympathetic nervous systems, as well as muscarinic receptors located in target organs of the parasympathetic nervous system, nicotinic receptors situated in skeletal muscle tissue, and the central nervous system. The association between human illnesses and environmental exposures to CBs have been extensively studied in several studies. Although CBs-triggered toxicity leads to overproduction of reactive oxygen species (ROS), the detailed association between the toxicity under CBs exposure and NFE2-related factor 2 (Nrf2) signaling pathways has not been completely clarified. In this review we aimed to summarize the latest findings on the functional interrelationship between carbamates compounds and Nrf2 signaling.

Emergency Medical Service responses as latent social capital toward Deliberate Self-Harm, Suicidality and Suicide

Escalation in Deliberate Self-Harm (DSH) is indicative of a rise in poor mental health and/or a failure of social and health services. The phenomenon of DSH exacerbates mental illness sequela, while being an essential indicator of suicide risk. Globally, about 800 000 people commit suicide yearly, averaging almost one suicide every 40 s. Based on a Retrospective Cross-Sectional Study, the aim sought to establish the scope of the DSH, suicidality and suicide case-load from a Western Cape Emergency Medical Services (EMS) prehospital perspective. A census of 3 years of EMS Incident Management Records (IMR) from a large rural district with seven local municipalities was undertaken using a novel data collection instrument. The 2976 (N) mental health-related incidents that met the inclusion criteria (from 413 712 cases) suggest a presentation rate of 7 per 1000 EMS calls. Sixty percent (n = 1776) were regarded to have deliberately self-harmed, attempted suicide or committed suicide. Overdose/deliberate self-poisoning accounted for 52% (n = 1550) of all the DSH caseload of the study. Attempted suicide accounted for 2.7% (n = 83) and Suicide for 3.4% (n = 102) of the suicidality case-load from the study, respectively. Suicide averaged 2.8. suicides per month in the Garden Route District over the 3-year period. Men were five times more likely to commit suicide than women, commonly using strangulation, while women mostly ingested household detergents and poison, and overdosed on chronic medication. Understandably, the EMS needs to assess its own capability to respond, treat, and transport health-care users with DSH and suicidality. This study demonstrates the EMS 'everyday' exposure to DSH, suicidality and suicide case-load. It represents a critical first step in the problem-space definition upon which a determination of the need for EMS responses can be based, to interrupt suicidality by removing methods of harm and strengthening the mental health economy through social capital investment.

Immuno-Kachiks formula immunomodulates and ameliorates hepatic damage induced by monosodium glutamate in rats

The immune system plays a vital role in controlling liver fibrosis and enhancing the pathogenesis of liver inflammation. Monosodium glutamate is a common flavor-enhancement food additive. This study evaluated the immunomodulatory and hepato-curative effects of the Immuno-Kachiks polyherbal formulation against monosodium glutamate-induced immune suppression and hepatic damage in rats. Monosodium glutamate was given orally at a 2000 mg/kg dose to male Wistar rats for three months to induce liver damage and immune suppression. After three months of successful induction, three groups were separately administered orally with Immuno-Kachiks formula at 400, 800, and 1500 mg/kg/day for 28 days. At the end of the treatment period, liver and blood samples were collected for histological and biochemical analysis. The lymphocyte count remained significantly low while the neutrophil count and the neutrophil-to-lymphocyte ratio increased significantly, despite the cessation of monosodium glutamate ingestion for 28 days. The Immuno-Kachiks formula (IKF) significantly increased the lymphocyte count, reduced the neutrophil-to-lymphocyte ratio, and normalized the neutrophil count. Neither monosodium glutamate nor the IKF significantly caused alpha-fetoprotein levels to rise or fall below normal. High doses (800 and 1500 mg/kg) of the Immuno-Kachiks formula significantly raised serum levels of aspartate aminotransferase, alkaline phosphatase, and total bilirubin. 1500 mg/kg of the IKF caused mild liver inflammation. The IKF restored the liver morphologic alterations observed in monosodium glutamate-induced liver damage in rats. The results suggest that the Immuno-Kachiks herbal formulation is a potential curative agent for early-stage liver damage and could restore suppressed adaptive immunity.

Glyphosate: Impact on the microbiota-gut-brain axis and the immune-nervous system, and clinical cases of multiorgan toxicity

Glyphosate (GLP) and GLP-based herbicides (GBHs), such as polyethoxylated tallow amine-based GLP surfactants (GLP-SH), developed in the late 70', have become the most popular and controversial agrochemicals ever produced. Nowadays, GBHs have reached 350 million hectares of crops in over 140 countries, with an annual turnover of 5 billion and 11 billion USD in the U.S.A. and worldwide, respectively. Because of the highly efficient inhibitory activity of GLP targeted to the 5-enolpyruvylshikimate-3-phosphate synthase pathway, present in plants and several bacterial strains, the GLP-resistant crop-based genetic agricultural revolution has decreased famine and improved the costs and quality of living in developing countries. However, this progress has come at the cost of the 50-year GBH overuse, leading to environmental pollution, animal intoxication, bacterial resistance, and sustained occupational exposure of the herbicide farm and companies' workers. According to preclinical and clinical studies covered in the present review, poisoning with GLP, GLP-SH, and GBHs devastatingly affects gut microbiota and the microbiota-gut-brain (MGB) axis, leading to dysbiosis and gastrointestinal (GI) ailments, as well as immunosuppression and inappropriate immunostimulation, cholinergic neurotransmission dysregulation, neuroendocrinal system disarray, and neurodevelopmental and neurobehavioral alterations. Herein, we mainly focus on the contribution of gut microbiota (GM) to neurological impairments, e.g., stroke and neurodegenerative and neuropsychiatric disorders. The current review provides a comprehensive introduction to GLP's microbiological and neurochemical activities, including deviation of the intestinal Firmicutes-to-Bacteroidetes ratio, acetylcholinesterase inhibition, excitotoxicity, and mind-altering processes. Besides, it summarizes and critically discusses recent preclinical studies and clinical case reports concerning the harmful impacts of GBHs on the GI tract, MGB axis, and nervous system. Finally, an insightful comparison of toxic effects caused by GLP, GBH-SH, and GBHs is presented. To this end, we propose a first-to-date survey of clinical case reports on intoxications with these herbicides.

Differences in the characteristics of people who purchase pesticides from shops for self-harm versus those who use pesticides available in the domestic environment in Sri Lanka

OBJECTIVE

Data from South Asia indicate that for 15%-20% of suicide attempts, pesticides are purchased from shops; otherwise, pesticides are obtained from an individual's house or nearby environment. We aimed to investigate the difference between individuals who directly purchase pesticides from shops for suicide attempts and suicide deaths versus those related to accessing the pesticides from an individual's house or nearby environment.

METHODS

We conducted two comparative studies in rural Sri Lanka: (1) non-fatal shop cases (n = 50) were survivors of self-poisoning with pesticides who ingested the pesticides after purchasing them from a shop; non-fatal domestic cases (n = 192) were survivors who accessed pesticides from their house or nearby environment. (2) fatal shop cases (n = 50) were individuals who died after ingesting pesticides they purchased for the act; fatal domestic cases (n = 102) were patients who died after ingesting pesticides they accessed at house or nearby environment. Logistic regression analysis was used to assess the characteristics which distinguished between the shop and domestic cases.

RESULTS

Data indicate that 20.7% and 32.9% of individuals who used pesticides for suicide attempts and suicide deaths had purchased them from shops, respectively. Being a non-farmer was the main distinguishing characteristic of shop cases: adjusted odds ratios (AOR) 8.9, 95% confidence intervals (CI) 3.2-24.4 for non-fatal shop cases, and AOR 4.0, 95% CI 1.5-10.6 for fatal shop cases. Non-fatal shop cases also had higher suicide intent (AOR 3.0, CI 1.0-8.9), and ingesting an insecticide (AOR 4.8, CI 1.8-1.0-8.9) than non-fatal domestic cases.

CONCLUSION

A high suicide intent of individuals who purchase pesticides for the event explains the high proportion of such fatal cases. Such high suicide intent makes the prevention implications difficult to spell out for those individuals who purchase pesticides for self-poisoning. However, our findings are valuable for clinicians to assess pesticide poisoning cases in hospitals.

Banning highly hazardous pesticides saves the lives of young people, particularly females, in low- and middle-income countries

Pesticide self-poisoning is a public health problem mostly affecting low- and middle-income countries. In Sri Lanka, India and China suicide rates have reduced among young people, particularly females, following highly hazardous pesticides (HHP) bans. This success story requires attention to encourage more research on differential effects of HHP bans.

Organophosphorus and carbamate pesticides: Molecular toxicology and laboratory testing

Population and food requirements are increasing daily throughout the world. To fulfil these requirements application of pesticides is also increasing. Organophosphorous (OP) and Organocarbamate (OC) compounds are widely used pesticides. These pesticides are used for suicidal purposes too. Both inhibit Acetylcholinesterase (AChE) and cholinergic symptoms are mainly used for the diagnosis of pesticide poisoning. Although the symptoms of the intoxication of OP and OC are similar, recent research has described different targets for OP and OC pesticides. Researchers believe the distinction of OP/OC poisoning will be beneficial for the management of pesticide exposure. OP compounds produce adducts with several proteins. There is a new generation of OP compounds like glyphosate that do not inhibit AChE. Therefore, it's high time to develop biomarkers that can distinguish OP poisoning from OC poisoning.

Impact of pesticide regulations on mortality from suicide by pesticide in China: an interrupted time series analysis

Background

Pesticide bans and regulatory restrictions have been shown to be effective strategies for preventing suicide in several countries. Suicide and suicide by pesticides have decreased significantly in China over the past two decades. However, whether the reduction was associated with pesticide regulation is unknown.

Methods

The monthly data on suicide and suicide by pesticide from 2006 to 2018 were obtained from China's Disease Surveillance Point (DSP) system. Information on China's pesticide regulations since 1970 was obtained from Pesticide Action Network International (PAN International), Joint Meeting on Pesticide Management Highly Hazardous Pesticides (JMPM HHP) lists, the website of the Ministry of Agriculture of China, Pesticide Information Network of China, and the Wan Fang database. Change point detection and policy analysis were combined to identify the time of any trend change breakpoint of suicide and suicide by pesticide. Interrupted time series analysis was used to investigate the pre- and post-breakpoint trends of monthly standardized rates in suicide and suicide by pesticide.

Results

The standardized pesticide suicide rate decreased by 60.5% from 6.50 in 2006 to 2.56 per 100,000 in 2018. Larger declines were evident among people in urban areas (67.3%), female individuals (63.5%), and people aged 15-44 years (68.1%). The effect of policies banning highly hazardous organophosphorus pesticides (HHOP) [rate ratio (RR) = 0.993, 95% CIs (0.991-0.994)] in December 2008 and stopping domestic sales and use of paraquat aqueous solution (RR = 0.992, 95% CIs: 0.990-0.994) in July 2016 were more pronounced than regulating the paraquat-related products (RR = 1.003, 95% CIs: 1.002-1.004) in April 2012.

Conclusion

Declines in suicide by pesticide in China occurred contemporaneously with regulatory bans and restrictions implemented on several pesticides, particularly in urban areas, among female individuals, and the relatively low age profile. These findings indicate the potential influence of these bans on trends of suicide by pesticides.

A lethal cocktail - shining a light on the relationship between alcohol use and pesticide self-poisoning

INTRODUCTION

Alcohol and pesticides are toxic substances that each cause acute and chronic harm to humans. Alcohol plays an important and complex role in pesticide self-poisoning, involving toxicological, public health, and social aspects important for research, prevention, and interventions.

ALCOHOL USE DISORDER AND SOCIAL HARMS

While the evidence on alcohol co-ingestion in the context of pesticide self-poisoning is limited, it appears that alcohol use increases complications. Even fewer studies address alcohol use disorder and dependence among pesticide self-poisoning patients. The harmful use of alcohol also impacts social life, families, and communities in several ways, including pesticide self-poisoning among individuals around the alcohol user. This, however, is vastly understudied.

OUTSIDE INFLUENCES

Agrochemicals and alcohol are produced by industries with financial interests, and the outcome of individual acts of pesticide self-poisoning depends on the lethality of the pesticide purchased and ingested. The promotion of acutely toxic pesticides by companies must be acknowledged within this issue.

CONCLUSION

The relationship between alcohol and pesticide self-poisoning is increasingly clear, but more studies are needed to guide management. We cannot ignore that pesticide self-poisoning and harmful use of alcohol occur within the context of wider, often structural, stressors and are influenced by commercial entities.

Additive screening and formula optimization of microbial inhibitor having disease prevention and growth promotion effects on Avena sativa

In order to develop environment friendly microbial inhibitor that can also control disease and promote oat (Avena sativa) growth, the growth rate method and response surface methodology were used to screen wetting agents, preservatives and protective agents at optimal concentrations in this study. Antagonistic activity of the tested bacterium and cell-free fermentation liquid against pathogenic fungi was evaluated on potato dextrose agar (PDA) substratum plates by dual culture technique. Oxford cup method was used to measure antagonistic reaction between screened bacteria. According to each screened bacteria with 50 mL were mixed and cultured in Luria-bertani (LB) substratum. Additives of Wetting agents, UV-protectors, and preservatives were screened by single factor test on the growth concentration of screened mixed bacteria. Afterwards, the optimal additives and concentrations were screened by Box-Behnken method. The microbial inhibitor was detected according to national standards GB20287-2006 and tested on oat in a pot experiment. The results showed that: (1) Functional bacteria which including Bacillus velezensis and Brevundimonas faecalis had control effects of 50.00% to 83.29% on three pathogenic fungi, and their cell free-fermentation liquid could inhibit the growth of pathogenic fungi from 23.51% to 39.90%; (2) Tween-80 was most suitable as wetting agents for Mix biocontrol bacteria (MBB) with 1.00% mass fraction; Sorbitol was selected as UV protective agents for MBB with 0.50% mass fraction. And methyl paraben was used as a preservative for MBB, with 0.50% mass fraction; (3) The most effective adjuvant contained 14.96 mL/L Tween-80, 5.12 g/L methylparaben and 5.6 g/L sorbitol; and (4) The microbial inhibitor controlled 45.57% of oat root rot and increased plant height, root length and seedling biomass. This study provides a suitable environment for the protection of mixed biocontrol bacteria, and lays a foundation for the prevention and control of oat diseases, the promotion of growth and the improvement of quality.

Treatment of cholinergic-induced status epilepticus with polytherapy targeting GABA and glutamate receptors

Despite new antiseizure medications, the development of cholinergic-induced refractory status epilepticus (RSE) continues to be a therapeutic challenge as pharmacoresistance to benzodiazepines and other antiseizure medications quickly develops. Studies conducted by Epilepsia. 2005;46:142 demonstrated that the initiation and maintenance of cholinergic-induced RSE are associated with trafficking and inactivation of gamma-aminobutyric acid A receptors (GABAA R) thought to contribute to the development of benzodiazepine pharmacoresistance. In addition, Dr. Wasterlain's laboratory reported that increased N-methyl-d-aspartate receptors (NMDAR) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR) contribute to enhanced glutamatergic excitation (Neurobiol Dis. 2013;54:225; Epilepsia. 2013;54:78). Thus, Dr. Wasterlain postulated that targeting both maladaptive responses of reduced inhibition and increased excitation that is associated with cholinergic-induced RSE should improve therapeutic outcome. We currently review studies in several animal models of cholinergic-induced RSE that demonstrate that benzodiazepine monotherapy has reduced efficacy when treatment is delayed and that polytherapy with drugs that include a benzodiazepine (eg midazolam and diazepam) to counter loss of inhibition, concurrent with an NMDA antagonist (eg ketamine) to reduce excitation provide improved efficacy. Improved efficacy with polytherapy against cholinergic-induced seizure is demonstrated by reduction in (1) seizure severity, (2) epileptogenesis, and (3) neurodegeneration compared with monotherapy. Animal models reviewed include pilocarpine-induced seizure in rats, organophosphorus nerve agent (OPNA)-induced seizure in rats, and OPNA-induced seizure in two mouse models: (1) carboxylesterase knockout (Es1-/- ) mice which, similarly to humans, lack plasma carboxylesterase and (2) human acetylcholinesterase knock-in carboxylesterase knockout (KIKO) mice. We also review studies showing that supplementing midazolam and ketamine with a third antiseizure medication (valproate or phenobarbital) that targets a nonbenzodiazepine site rapidly terminates RSE and provides further protection against cholinergic-induced SE. Finally, we review studies on the benefits of simultaneous compared with sequential drug treatments and the clinical implications that lead us to predict improved efficacy of early combination drug therapies. The data generated from seminal rodent studies of efficacious treatment of cholinergic-induced RSE conducted under Dr. Wasterlain's guidance suggest that future clinical trials should treat the inadequate inhibition and temper the excess excitation that characterize RSE and that early combination therapies may provide improved outcome over benzodiazepine monotherapy.

Intermediate Syndrome Due to Organophosphate Poisoning: A Case Report

Organophosphates, also known as phosphate esters, are a category of pesticide compounds that function by indirectly inhibiting the activity of an enzyme called acetylcholinesterase (AChE). AChE is responsible for breaking down acetylcholine (ACh) at the neuromuscular junction into acetic acid and choline. These compounds cause various clinical presentations upon acute toxicity, among which intermediate syndrome (IMS) exhibits an unpredictable course. This report describes the case of a farmer who ingested monocrotophos and ethanol in a suicide attempt, leading to a prolonged stay in the hospital and invasive ventilation, along with complications including ventilator-associated pneumonia. The patient received a total of 9000 mg of atropine over his 14-day hospitalization period.

The role of a combination of N-acetylcysteine and magnesium sulfate as adjuvants to standard therapy in acute organophosphate poisoning: A randomized controlled trial

Background

Mortality in acute organophosphate (OP) poisoning remains high despite current standard therapy with atropine and oximes. Due to dose-limiting side effects of atropine, novel therapies are targeting other putative mechanisms of injury, including oxidative damage, to reduce atropine dosage.

Objectives

N-acetylcysteine (NAC) and magnesium sulfate (MgSO₄) have different mechanisms of actions and should act synergistically in OP poisoning. In this study, we wanted to evaluate whether this novel combination, used as an adjuvant to standard care, could improve clinical outcomes.

Methods

The study was conducted in the Emergency Department and ICU of AIIMS Bhubaneswar (a tertiary care center and government teaching institute) between July 2019 and July 2021. Eighty-eight adult patients with history and clinical features of acute OP poisoning were randomly allocated (1:1) into two groups. The Study group received 600 mg NAC via nasogastric tube thrice daily for 3 days plus a single dose of 4 g Inj. MgSO₄ IV on first day and the Control group received suitably matched placebo (double-blinding) - in addition to standard care in both the groups. The primary outcome measure was to compare the total dose of Inj. Atropine required (cumulative over the entire treatment duration) between the control group and the study group receiving NAC and MgSO₄. The secondary outcome measures were lengths of ICU and hospital stays, need and duration of mechanical ventilation, the differences in BuChE activity, oxidative stress biomarkers - MDA and GSH levels, the incidences of adverse effects including delayed sequalae like intermediate syndrome and OPIDN, and comparison of mortality between the two groups.

Results

Data from 43 patients in Control and 42 patients in Study group was finally analyzed. The baseline parameters were comparable. Total atropine requirements were lower in the Study group [175.33 ± 81.25 mg (150.01-200.65)] compared to the Control [210.63 ± 102.29 mg (179.15-242.11)] [Mean ± SD (95% CI)], but was not statistically significant. No significant differences in any of the other clinical or biochemical parameters were noted.

Conclusion

The N-acetylcysteine and MgSO₄ combination as adjuvants failed to significantly reduce atropine requirements, ICU/hospital stay, mechanical ventilatory requirements, mortality and did not offer protection against oxidative damage.

Organophosphate Toxicity Presenting as a Stroke Alert

Altered mental status is a common emergency department presentation. It has a broad differential and can be particularly challenging when the patient is unable to give a history and collateral information is not immediately available. The authors present a case of altered mental status initially brought in as a stroke alert but later discovered to be intentional organophosphate ingestion. Although organophosphate poisoning is relatively rare in the United States, it should be considered in patients with altered mental status with miosis who are unresponsive to naloxone, especially in the setting of bradycardia or copious secretions.

Agriculture without paraquat is feasible without loss of productivity-lessons learned from phasing out a highly hazardous herbicide

A small proportion of the thousands of pesticides on the market today are associated with a disproportionately high incidence of severe acute pesticide poisoning and suicide. Paraquat stands out as one of the most lethal pesticides in common use, frequently involved in fatal incidents due to suicides or accidental exposure. Even though paraquat has been banned in over 67 countries, it is still widely used in many others, particularly in Asia and Latin America. Based on a literature review and consultations, this paper identifies options for replacing paraquat and distils practical lessons from numerous successes around the world. Our aim is to support regulators, policymakers, agronomists and the supply chain sector with practical information related to phasing out paraquat. Production data consistently failed to show any negative effects of banning paraquat on agricultural productivity. A wide range of alternative approaches to weed management and crop defoliation are available, many of which do not rely on herbicides. Over 1.25 million farmers in low- and middle-income countries (LMICs) successfully produce a range of crops for private voluntary standards (PVS) in food and fiber supply chains which prohibit paraquat use. We conclude from the findings of this study that eliminating paraquat will save lives without reducing agricultural productivity. Less hazardous and more sustainable alternatives exist. To enhance successful adoption and uptake of these methods on a wide scale, farmers require training and support within an enabling policy environment.

High hazzard pesticides (HHPs) in Near East and North Africa (NENA), constrains and recommendations to mitigate the risk of HHPs

This study presents an overview of the current situation of highly hazardous pesticides (HHPs) in North Africa and Near East countries (NENA). This work reviews the registered pesticides in the region and identify HHPs being used according to the criteria 1-8 for HHPs of FAO/WHO Guidelines on HHPs. In addition, to identify the weakness and the need of the region to mitigate the risk from the use of HHPs, the report ended with recommendations needed in the region to improve the pesticide managements and registration, such as improving the agricultural practices by adopting the integrated pest management IPM and including replacing HHPs with ecosystem-friendly alternatives if available. The total number of pesticides registered and used in NENA region is 642 active ingredients (IA). Eighty-nine HHPs are still in use in NENA region and 50% of them are evaluated under 1-7 criteria of GHS HHPs. This evaluation shows that 50% of HHPs are insecticides, 22% fungicides, 10% herbicides, 8% nematocides, and 10% rodenticides. The rest of 38 HHPs are identified under criteria 8. This high number of HHPs still in use in some NENA countries urges the need of technical assistance to reduce the use of HHPs. The type of assistant varies from country to other; to identify the priority of technical and legal assistant needed, a country-based assessments must be carried out at the near future.

Suicide rates among people with serious mental illness: a systematic review and meta-analysis

BACKGROUND

People with serious mental illness are at great risk of suicide, but little is known about the suicide rates among this population. We aimed to quantify the suicide rates among people with serious mental illness (bipolar disorder, major depression, or schizophrenia).

METHODS

PubMed and Web of Science were searched to identify studies published from 1 January 1975 to 10 December 2020. We assessed English-language studies for the suicide rates among people with serious mental illness. Random-effects meta-analysis was used. Changes in follow-up time and the suicide rates were presented by a locally weighted scatter-plot smoothing (LOESS) curve. Suicide rate ratio was estimated for assessments of difference in suicide rate by sex.

RESULTS

Of 5014 identified studies, 41 were included in this analysis. The pooled suicide rate was 312.8 per 100 000 person-years (95% CI 230.3-406.8). Europe was reported to have the highest pooled suicide rate of 335.2 per 100 000 person-years (95% CI 261.5-417.6). Major depression had the highest suicide rate of 534.3 per 100 000 person-years (95% CI 30.4-1448.7). There is a downward trend in suicide rate estimates over follow-up time. Excess risk of suicide in males was found [1.90 (95% CI 1.60-2.25)]. The most common suicide method was poisoning [21.9 per 100 000 person-years (95% CI 3.7-50.4)].

CONCLUSIONS

The suicide rates among people with serious mental illness were high, highlighting the requirements for increasing psychological assessment and monitoring. Further study should focus on region and age differences in suicide among this population.

A rapid and reliable immunochromatographic strip for detecting paraquat poinsoning in domestic water and real human samples

Paraquat (PQ) is one of the most commonly used herbicides, but it has polluted the environment and threatened human health through extensive and improper usage. Here, a new naked-eye PQ immunochromatographic strip was developed to recognize PQ in domestic water and real human samples within 10 min based on a novel custom-designed anti-PQ antibody. The PQ test strip could recognize PQ at a concentration as low as 10 ng/ml, reaching the high-efficiency time-of-flight mass spectrometry detection level and identifying trace amounts of PQ in samples treated with a diquat (DQ) and PQ mixture. Notably, both the performance evaluation and clinical trial of the proposed PQ strips were validated in multiple hospitals and public health agencies. Taken together, our study firstly provide the clinical PQ-targeted colloidal gold immunochromatographic test strip designed both for environment water and human sample detection with multiple advantages, which are ready for environmental monitoring and clinical practice.

Environmental toxicity risk evaluation of nitroaromatic compounds: Machine learning driven binary/multiple classification and design of safe alternatives

Nitroaromatic compounds (NACs) represent a significant source of organic pollutants in the environment. In this study, a well-rounded dataset containing 371 NACs with rat oral median lethal doses (LD50s) was developed. Based on the dataset, binary and multiple classification models were established. Seven machine learning algorithms were used to establish the prediction models in combination with six fingerprints. In the binary classification models, the overall predictive accuracy of 10-fold cross-validation for training set in the top ten models ranged from 0.823 to 0.874. In the multiple classification models, the combination of graph fingerprint and random forest (Graph-RF) yielded the best predictive effects with AUC values of 0.929 and 0.956 for the training set and the test set, respectively. Model prediction performance was further evaluated using the true external set comprising 1366 NACs, including 96.6% belonging to the applicability domain. Further, we determined the structural features influencing the acute oral toxicity based on information gain and substructure frequency analysis. Finally, we identified highly toxic compounds based on the structural alerts and successfully transformed a representative highly toxic compound into low-toxic alternatives via structural modification. Overall, the models constructed facilitate environmental risk assessment and the design of green and safe chemicals.

Exploring China stepping into the dawn of chemical pesticide-free agriculture in 2050

China has implemented a series of policies to reduce the usage of chemical pesticides to maintain food production safety and to reduce water and soil pollution. However, there is still a huge gap in developing biological pesticides to replace chemical agents or managing pests to prevent crop production loss. It is necessary to predict the future use of chemical pesticides and to exploit the potential ways to control pests and crop diseases. Pesticide usage is affected by seasonal changes and analyzed by using a seasonal autoregressive integrated moving average (ARIMA) model (a statistical model that predicts future trends using time-series data). The future development of biopesticides in China was predicted using the compound annual growth rate (CAGR), which is calculated via the equation [(Final value/Starting value)1/years - 1] according to the annual growth rate of target products over time. According to the reducing trend of pesticide and biological pesticide usage annually, China is predicted possibly step into the era of pesticide-free agriculture in 2050 based on the analysis of the ARIMA model. With CAGR calculation, China will produce from 500 thousand to one million tons of biopesticides in 2050, which can meet the need to replace chemical pesticides in agriculture to prevent the present crop production loss. To achieve the goal, China still has the greatest challenges to develop biopesticides and use various strategies to control pest and crop diseases. China may step into the dawn of chemical pesticide-free agriculture in 2050 if biopesticides can be developed smoothly and pests can be controlled well using various strategies.

Organophosphorus Poisoning among Patients Admitted to the Intensive Care Unit of the Department of Internal Medicine in a Tertiary Care Centre: A Descriptive Cross-sectional Study

INTRODUCTION

Organophosphates are potent cholinesterase inhibitors that when ingested in excessive amounts can be fatal. Organophosphorus poisoning has become an important clinical problem with increased mortality in the country from accidental or intentional ingestion of, or exposure to the pesticide. This study aimed to find out the prevalence of organophosphorus poisoning among patients admitted to the Intensive Care Unit of the Department of Internal Medicine in a tertiary care centre.

METHODS

A descriptive cross-sectional study was conducted among patients admitted to the Intensive Care Unit of the Department of Internal Medicine of a tertiary care centre after receiving ethical approval from the Institutional Review Committee (Reference number: 2003202205). The study was conducted between 1 February 2021 and 1 February 2022 using hospital records. Convenience sampling was done among the patients who met the eligibility criteria. The diagnosis of organophosphorus poisoning was made based on the patient's history, clinical examination and the measurement of serum acetylcholinesterase levels. Point estimate and 95% Confidence Interval were calculated.

RESULTS

Among 1108 patients admitted, organophosphorus poisoning was seen in 50 (4.15%) (3.29-5.73, 95% Confidence Interval).

CONCLUSIONS

Our study found that the prevalence of organophosphorus poisoning was lower when compared to similar studies done in similar settings.

Acute fungicide self-poisoning - a prospective case series

BACKGROUND

Pesticide self-poisoning is a global clinical and public health problem. While self-poisoning with insecticides and herbicides has been extensively studied, there is minimal literature on acute fungicide self-poisoning. We aimed to study the clinical course and outcome of fungicide self-poisoned patients recruited to a prospective cohort in Sri Lanka.

METHODS

We conducted a prospective study of patients presenting with fungicide self-poisoning to nine hospitals in Sri Lanka between 2002 and 2020. Patients were enrolled by clinical research assistants, with clinical outcomes being recorded at regular review for each patient.

RESULTS

We identified 337 cases of self-poisoning with fungicides (alcohol as only co-ingestant), including 28 different fungicides across 5 different fungicide classes. Median time from ingestion to examination was 3.1 (1.8-5.7) h. Nearly all presented to hospital fully conscious (GCS 15, 15-15)- only 27 patients (8.0%) presented with reduced GCS (<15) and only 2 (0.6%) had GCS 3/15. Most patients (333/337, 98.8%) made a full recovery, of whom only eight (2.37%) required intubation and ventilation. Four patients died (case fatality rate: 1.2%; 95% CI 0.0-23.4) after ingestion of edifenphos (n = 2), propamocarb and pyraclostrobin.

CONCLUSION

Fungicide self-poisoning appears to be less hazardous than insecticide or herbicide self-poisoning, with a substantially lower case fatality in the same cohort. Edifenphos is an exception to this 'less toxic' rule; as a WHO Class Ib highly hazardous pesticide, we recommend its withdrawal from, and replacement in, global agricultural practice. Propamocarb should be listed in the WHO hazard classification as propamocarb hydrochloride to reflect the higher toxicity of the common agricultural formulation. Pyraclostrobin currently has no WHO classification; one is urgently required now that its ingestion has now been linked the death of a patient. Additional prospective clinical data on fungicide self-poisoning is required to expand knowledge on the effects of these diverse compounds.

Perception of the criminality of attempted suicide in Nepal and its impact on suicide reporting

In 2018-2019, according to the official statistics, 5754 people died as a result of suicide in Nepal. This is a high number for a country with a population of 29 million people. Experts believe that the actual rate is considerably higher and that many suicides are not reported. This underreporting of suicide is frequently blamed on the stigma and the criminality of attempted suicide. Yet, there has never been a criminal liability for attempted suicide in Nepal. This article discusses the reasons for the perception of the criminality of attempted suicide in the country, its consequences, and the ways of addressing them. We found that the involvement of the police at the initial stages of suicide investigation confirms public perceptions that attempted suicide is a punishable offense and this may reinforce the stigma of suicide. Recent criminalization of the abetment of suicide has contributed to this perception as the public may not be clear about the distinction between abetment of suicide and attempted suicide. Criminalization of suicide not in the laws but in minds discourages reporting and help-seeking behaviour and victimizes people who need support and services. We argue that decriminalization is more than removing the outdated legal clauses from the legal statutes, but also public awareness raising about the reasons for police investigation of suspicious deaths, sensitivity training, and education of government officials, policymakers, and police about suicide and its prevention. These are needed to dispel the myth of criminalization of attempted suicide in Nepal. Our findings could be of wider interest to scholars working on reducing the stigma of suicide and decriminalization of suicide attempts.

Recent advances on botanical biosynthesis of nanoparticles for catalytic, water treatment and agricultural applications: A review

Green synthesis of nanoparticles using plant extracts minimizes the usage of toxic chemicals or energy. Here, we concentrate on the green synthesis of nanoparticles using natural compounds from plant extracts and their applications in catalysis, water treatment and agriculture. Polyphenols, flavonoid, rutin, quercetin, myricetin, kaempferol, coumarin, and gallic acid in the plant extracts engage in the reduction and stabilization of green nanoparticles. Ten types of nanoparticles involving Ag, Au, Cu, Pt, CuO, ZnO, MgO, TiO₂, Fe₃O₄, and ZrO₂ with emphasis on their formation mechanism are illuminated. We find that green nanoparticles serve as excellent, and recyclable catalysts for reduction of nitrophenols and synthesis of organic compounds with high yields of 83-100% and at least 5 recycles. Many emerging pollutants such as synthetic dyes, antibiotics, heavy metal and oils are effectively mitigated (90-100%) using green nanoparticles. In agriculture, green nanoparticles efficiently immobilize toxic compounds in soil. They are also sufficient nanopesticides to kill harmful larvae, and nanoinsecticides against dangerous vectors of pathogens. As potential nanofertilizers and nanoagrochemicals, green nanoparticles will open a revolution in green agriculture for sustainable development.

Lung injury caused by aspiration of organophosphorus insecticide and gastric contents in pigs

INTRODUCTION

Patients who require mechanical ventilation after self-poisoning with ingested organophosphorus (OP) insecticides often die. Aspiration of stomach contents may contribute to lung injury and lethality. This study was designed to assess the severity of direct and indirect pulmonary injury created by pulmonary instillation of mixtures of OP insecticide, solvent (Solv) and porcine gastric juice (GJ) compared to controls.

METHODS

Terminally anaesthetised minipigs (groups n = 5) were exposed to sham bronchoscopy or given mixtures (0.5 mL/kg) of: saline, GJ, OP insecticide and GJ (OP + GJ), or Solv and GJ (Solv + GJ), placed into the right lung, and monitored for 48 h. Lung injury was assessed through analysis of bronchoalveolar lavage fluid (BALF), computed tomography and histopathology.

RESULTS

OP + GJ created a direct lung injury consisting of neutrophil infiltration, oedema and haemorrhage, as well as indirect injury to the other lung. OP + GJ directly-injured lung parenchyma had increased concentrations of BALF protein, albumin, IL-6, IL-8 and C-reactive protein (CRP) at 24 h (p < 0.05), and BALF protein, albumin and CRP at 48 h (p < 0.05), when compared with controls. Aspiration of GJ produced similar direct effects to OP + GJ but less indirect lung injury. Lung injury was less severe after Solv + GJ, for combined lung histopathology scores (vs. OP + GJ, p < 0.05) and for the proportion of directly-injured lung that was poorly/non-aerated at 48 h.

CONCLUSION

Pulmonary instillation of OP + GJ created more lung damage than controls or Solv + GJ. In patients with severe OP insecticide poisoning and reduced consciousness, early airway protection is likely to reduce pulmonary damage.

Pesticide use, agricultural outputs, and pesticide poisoning deaths in Japan

OBJECTIVE

Although pesticide poisonings occur worldwide, most high-income countries have not been severely affected. Japan is a key exception, with pesticide suicides becoming a major public health concern in the 1980s. We here report the epidemiology of lethal pesticide poisoning in Japan in relation to its pesticide regulation and agricultural output.

METHODS

We obtained data on pesticide registration and sales from the Japan Plant Protection Association's annual Pesticide Handbook, National Food and Agricultural Materials Inspection Center, and Food and Agriculture Organization of the United Nations. Data on deaths due to pesticide poisoning and population were obtained from Vital Statistics of Japan. We reviewed the registration status and hazard classification of pesticides in Japan and analysed the relationships between the use/sales, pesticides fatalities, and agricultural output.

RESULTS

Five hundred and twenty-nine pesticide active ingredients are currently registered in Japan, including four WHO hazard class IB organophosphorus and carbamate insecticides. Paraquat was registered in 1962 as a liquid SL20 formulation. In 1986, restrictions were imposed on its sale/use and a 4.3% paraquat ion/4.1% diquat ion combination product registered by ICI. There were 221 pesticide poisoning fatalities in 2019, down from 2648 in 1986, a 92% reduction over 33 years. Self-poisoning was responsible for most pesticide deaths in both 1985 (2013/2476, 81.3%) and 2019 (146/221, 66.1%). Pesticide poisoning made up 8.6% of all suicides in 1985, down to 0.7% in 2019. Unintentional pesticide poisoning deaths also all fell by 83.8%, from 463 to 75. These reductions were associated with reduced sales of both OP/carbamate insecticides and paraquat/diquat but no apparent change in agricultural output across a broad range of crops.

CONCLUSIONS

Reduced use of highly hazardous pesticides and lowered concentration formulations in Japan were associated with major decreases in all deaths from pesticide poisoning and the proportion of all suicides due to pesticide ingestion.

Impact of large-scale, government legislated and funded organic farming training on pesticide use in Andhra Pradesh, India: a cross-sectional study

BACKGROUND

The use of pesticides in agriculture has been associated with the destruction of biodiversity and damage to human health. A marked reduction in pesticide use is urgently required globally, but whether this can be achieved rapidly and at scale is unclear. We aimed to assess whether government-legislated and funded organic farming training in Andhra Pradesh, India, reduced pesticide use by farmers and sales of pesticides by pesticide retailers.

METHODS

We did a cross-sectional survey between Aug 11 and Nov 26, 2020, among farmers and pesticide retailers in Kurnool District of Andhra Pradesh (India). We assessed the impact of the Andhra Pradesh Community Managed Natural Farming (APCNF) programme, which aims to transition 100% of the agricultural land of Andhra Pradesh (population approximately 49 million, 6 million of whom are farmers) to organic farming practices by 2030. We did cross-sectional phone interview surveys of farmers and face-to-face surveys of pesticide retailers. We used multivariable Poisson regression models to estimate relative risks (RRs) and logistic regression models to estimate odds ratios (ORs).

FINDINGS

962 farmers were invited to participate, of whom 894 (93%) consented (709 conventional farmers and 149 APCNF farmers). 47 pesticide retailers were invited to participate, of whom 38 (81%) consented. APCNF farmers had practised APCNF for a median of 2 years (IQR 1-3). APCNF farmers were less likely to use pesticides than conventional farmers (adjusted RR 0·65 [95% CI 0·57-0·75]), although pesticide use remained high among both APCNF and conventional farmers (73 [49%] of 148 APCNF farmers vs 695 [99%] of 700 conventional farmers; p<0·0001). APCNF farmers had lower pesticide expenditures than conventional farmers (median US$0 [IQR 0-170] for APCNF farmers vs $175 [91-281] for conventional farmers; p=0·0001). Increased frequency of meeting with agricultural extension workers was associated with reduced pesticide use among ACPNF farmers. Seven (18%) of 38 retailers reported a decrease in sales of pesticides in the past 4 years; no difference in the odds of reporting a decrease in pesticide sales in the past 4 years was identified between APCNF retailers and conventional retailers (OR 0·95 [95% CI 0·58-1·57]).

INTERPRETATION

Despite a major government drive for organic agriculture, about half of APCNF farmers continued to use pesticides and no impact on pesticide sales at local retailers was observed. A combination of policy instruments (eg, bans on highly hazardous pesticides), not solely training for farmers, might be needed to eliminate pesticide use in agriculture.

FUNDING

Scottish Funding Council and UK Research and Innovation.

Death in the paddy field: Carcass decomposition and associated arthropods in subunits of a rice field landscape

Although rice production landscapes are often the scene of homicides, vertebrate decomposition and associated arthropods have never been described from rice paddies. Tropical rice landscapes are typically composed of irrigated/non-irrigated rice fields, fallow land (i.e., uncultivated fields), and low earthen levees (bunds) used as access pathways. The specific microclimatic and environmental conditions associated with each subunit of rice field landscapes are likely to impact carcass decomposition as well as the arthropod species associated with carrion. Here, we tested the hypothesis that the combined effects of constraints on arthropod colonization and survival, scarcity of necromass, limited habitat architecture, and recurrent disturbance limit the ability of carrion-related arthropods to colonize corpses and large carcasses in tropical rice-fields. Our results from monitoring pig carcasses in Philippine rice fields indicated that vertebrate decomposition in irrigated fields was slower and incomplete when compared to non-irrigated fields and bunds. Carcasses were colonized by a small complex of carrion-related arthropods that differed in composition and relative species abundance between dry bunds and relatively humid rice paddies. Fire ants (Solenopsis germinata) were observed frequently on carcasses exposed on bunds, rarely in non-irrigated fields, and almost never in irrigated fields. The presence of fire ants was associated with reduced blow fly (Chrysomya megacephala) abundance. Taken together, this indicates that the arthropod fauna associated with carcasses in tropical rice fields is relatively simple in contrast to the generally high arthropod diversity reported for other ecosystems at tropical latitudes. The limited richness of the community also means that an understanding of the development of one abundant calliphorid blow fly, C. megacephala, may be sufficient to investigate deaths and homicides under conditions similar to the ones described in this study.

Highly sensitive and selective rGO based Non-Enzymatic electrochemical sensor for propamocarb fungicide pesticide detection

In this study, reduced graphene oxide (rGO) was prepared using a green ultrasonic microwave assisted method and investigated rGO based non-enzymatic electrochemical sensor for detecting a synthetic fungicide as a propamocarb (PM) pesticide. The rGO-based sensor exhibited rapid response within 1 min, low detection limit of 0.6 μM and wide linear range of (1-5) μM with a high sensitivity of 101.1 μAμM^-1 cm^-2 for PM. Besides this, the sensor detected the propamocarb pesticide on the real cucumber sample with high sensitivity in the concentration range of (1-5) μM within a 1-minute cycle. The sensor is highly selective against propamocarb pesticide. The prepared non-enzymatic electrochemical sensor exhibited high sensitivity, high selectivity, reproducibility, and rapid response.

CON: Oximes should be used routinely in organophosphorus insecticide poisoning

Organophosphorus (OP) insecticide poisoning causes respiratory failure due to acetylcholinesterase (AChE) inhibition. The AChE reactivating antidote pralidoxime was developed in the 1950s and soon noted to benefit patients occupationally poisoned with the highly potent OP insecticide parathion. Routine use of pralidoxime and other oximes such as obidoxime then became widely recommended. However, nearly all severe cases of OP poisoning now result from self-poisoning with large volumes of less potent (WHO hazard class Ib and II) insecticides and co-formulated solvents. Unfortunately, oxime clinical trials have never shown benefit from their use for these patients, and some have shown that pralidoxime may be associated with harm, including increased mortality. Oximes should not be used routinely for the care of OP insecticide poisoned patients until translational and clinical studies have identified a safe and effective oxime regimen and identified the patients who benefit.

Hemoperfusion in combination with hemofiltration for acute severe organophosphorus pesticide poisoning: A systematic review and meta-analysis

Background:

Acute severe organophosphorus pesticide poisoning (ASOPP) is one of the major diseases that endanger human life and health. However, the effects of conventional therapy including gastric lavages, mechanical ventilation, muscarinic antagonist drugs, and cholinesterase reactivators were uncertain. This meta-analysis aims to investigate the safety and efficacy of hemoperfusion combined with hemofiltration besides routine therapy for ASOPP.

Materials and Methods:

A comprehensive search for candidate publications was performed through PubMed, Medline, Cochrane Library, WanFang, Chinese Biomedical Literature, and China National Knowledge Infrastructure from database inception to May 12, 2020. The retrieved studies were screened by the predefined inclusion and exclusion criteria. The data of important end points were extracted. The risk ratio (RR) and weighted mean difference (WMD) were pooled for categorical variables and continuous variables, respectively. Meta-analyses and publication bias were conducted by using STATA software version 15.1.

Results:

A total of 11 randomized controlled trials with 811 patients were included. Compared to conventional therapy group, patients in the hemoperfusion plus hemofiltration group were significantly superior with regard to mortality (RR 0.38, 95% confidence interval [CI] [0.25, 0.57], P < 0.001), total atropine dosing (WMD −147.34 mg, 95% CI [−199.49, −95.18], P < 0.001), duration of mechanical ventilation (WMD −2.34 days, 95% CI [−3.77, −0.92], P < 0.001), cholinesterase recovery time (WMD −2.49 days, 95% CI [−3.14, −1.83], P < 0.001), and length of stay (WMD −4.52 days, 95% CI [−5.31, −3.73], P < 0.001).

Conclusion:

Combined hemoperfusion and hemofiltration was a very safe and effective treatment protocol for ASOPP, not only resulting in significantly decreased mortality but also resulting in reduced total atropine dosing, duration of mechanical ventilation, cholinesterase recovery time, and length of stay.

Antagonistic postsynaptic and presynaptic actions of cyclohexanol on neuromuscular synaptic transmission and function

Intentional ingestion of agricultural organophosphorus insecticides is a significant public health issue in rural Asia, causing thousands of deaths annually. Some survivors develop a severe, acute or delayed myasthenic syndrome. In animal models, similar myasthenia has been associated with increasing plasma concentration of one insecticide solvent metabolite, cyclohexanol. We investigated possible mechanisms using voltage and current recordings from mouse neuromuscular junctions (NMJs) and transfected human cell lines. Cyclohexanol (10-25 mM) reduced endplate potential (EPP) amplitudes by 10-40% and enhanced depression during repetitive (2-20 Hz) stimulation by up to 60%. EPP decay was prolonged more than twofold. Miniature EPPs were attenuated by more than 50%. Cyclohexanol inhibited whole-cell currents recorded from CN21 cells expressing human postjunctional acetylcholine receptors (hnAChR) with an IC₅₀ of 3.74 mM. Cyclohexanol (10-20 mM) also caused prolonged episodes of reduced-current, multi-channel bursting in outside-out patch recordings from hnAChRs expressed in transfected HEK293T cells, reducing charge transfer by more than 50%. Molecular modelling indicated cyclohexanol binding (-6 kcal/mol) to a previously identified alcohol binding site on nicotinic AChR α-subunits. Cyclohexanol also increased quantal content of evoked transmitter release by ∼50%. In perineurial recordings, cyclohexanol selectively inhibited presynaptic K⁺ currents. Modelling indicated cyclohexanol binding (-3.8 kcal/mol) to voltage-sensitive K⁺ channels at the same site as tetraethylammonium (TEA). TEA (10 mM) blocked K⁺ channels more effectively than cyclohexanol but EPPs were more prolonged in 20 mM cyclohexanol. The results explain the pattern of neuromuscular dysfunction following ingestion of organophosphorus insecticides containing cyclohexanol precursors and suggest that cyclohexanol may facilitate investigation of mechanisms regulating synaptic strength at NMJs. KEY POINTS: Intentional ingestion of agricultural organophosphorus insecticides is a significant public health issue in rural Asia, causing thousands of deaths annually. Survivors may develop a severe myasthenic syndrome or paralysis, associated with increased plasma levels of cyclohexanol, an insecticide solvent metabolite. Analysis of synaptic transmission at neuromuscular junctions in isolated mouse skeletal muscle, using isometric tension recording and microelectrode recording of endplate voltages and currents, showed that cyclohexanol reduced postsynaptic sensitivity to acetylcholine neurotransmitter (reduced quantal size) while simultaneously enhancing evoked transmitter release (increased quantal content). Patch recording from transfected cell lines, together with molecular modelling, indicated that cyclohexanol causes selective, allosteric antagonism of postsynaptic nicotinic acetylcholine receptors and block of presynaptic K⁺ -channel function. The data provide insight into the cellular and molecular mechanisms of neuromuscular weakness following intentional ingestion of agricultural organophosphorus insecticides. Our findings also extend understanding of the effects of alcohols on synaptic transmission and homeostatic synaptic function.

A Microbial Electrochemical Technology to Detect and Degrade Organophosphate Pesticides

Organophosphate (OP) pesticides cause hundreds of illnesses and deaths annually. Unfortunately, exposures are often detected by monitoring degradation products in blood and urine, with few effective methods for detection and remediation at the point of dispersal. We have developed an innovative strategy to remediate these compounds: an engineered microbial technology for the targeted detection and destruction of OP pesticides. This system is based upon microbial electrochemistry using two engineered strains. The strains are combined such that the first microbe (E. coli) degrades the pesticide, while the second (S. oneidensis) generates current in response to the degradation product without requiring external electrochemical stimulus or labels. This cellular technology is unique in that the E. coli serves only as an inert scaffold for enzymes to degrade OPs, circumventing a fundamental requirement of coculture design: maintaining the viability of two microbial strains simultaneously. With this platform, we can detect OP degradation products at submicromolar levels, outperforming reported colorimetric and fluorescence sensors. Importantly, this approach affords a modular, adaptable strategy that can be expanded to additional environmental contaminants.

Effect of paraquat on cytotoxicity involved in oxidative stress and inflammatory reaction: A review of mechanisms and ecological implications

Paraquat (PQ) is a cheap and an effective herbicide, which is widely being used worldwide to remove weeds in cultivated crop fields. However, it can cause soil and water pollution, and pose serious harm to the environment and organisms. Several countries have started to limit or prohibit the use of PQ because of the increasing number of human deaths. Its toxicity can damage the organisms with a multi-target mechanism, which has not been fully understood yet. That is why it is hard to treat as well. The current research on PQ focuses on its targeted organ, the lungs, in which PQ mostly trigger pulmonary fibrosis. While there is a lack of systematic research, there are few studies published discussing its toxic effects at systematic level. This review summarizes the major damages caused by PQ in different organisms and partial mechanisms by which it causes these damages. For this purpose, we consulted several research articles that studied the toxicity of PQ in various tissues. We also listed some drugs that can be used to alleviate the toxicity of PQ. However, at present, the effectiveness of these drugs is still being explored in animal experiments and the study of their mechanism will also help in understanding the poisoning mechanism of PQ, which will ultimately lead to effective treatment in future.

Importance of pesticides for lethal poisoning in India during 1999 to 2018: a systematic review

BACKGROUND

Poisoning is a major problem in India. However, there is little systematic information on the key poisons responsible for most deaths by geographical area and over time. We aimed to review the literature to identify the poison classes causing the greatest number of deaths in India over the last 20 years.

METHODS

We performed a systematic literature review in Medline, Embase and Google Scholar (1999-2018), and Indian online medical journals, to find papers that reported deaths from all forms of poisoning in India, with last search 20 April 2020. We included epidemiological studies, observational studies, randomised trials, interventional studies, and case series published from 1999 to 2018 that showed the number of deaths and autopsy studies indicating the specific poisons or poison classes. Studies providing the case fatality for specific poisons or classes, which enabled calculation of the number of deaths, were also included. We excluded deaths due to animal bites and stings, ethanol or methanol poisoning, and gas inhalation as well as papers reporting a single death (case study of single patient). We grouped the papers into 5-year intervals and identified the two most common poison classes in each paper. We used descriptive statistics to summarise the findings over time based on the causative poison and the location of the study.

RESULTS

We identified 186 papers reporting 16,659 poisoning deaths between 1999 and 2018. The number of publications per 5-year interval showed no clear trend over the period (48, 38, 67, and 36 for consecutive periods). Half of the deaths (n = 8338, 50.0%) were reported during the first 5 years of the study (1999-2003), the number of deaths declining thereafter (to n = 1714 in 2014-2018). Deaths due to pesticide poisoning (94.5%) were dominant across the study period compared to other classes of poison [hair dye paraphenylenediamine poisoning (2.6%), medicine overdose (1.4%) or plant poisoning (1.0%)]. Among the pesticides, aluminium phosphide was the most important lethal poison during the first 10 years before declining markedly; organophosphorus insecticides were important throughout the period, becoming dominant in the last decade as aluminium phosphide cases declined. Unfortunately, few papers identified the specific organophosphorus insecticide responsible for deaths.

CONCLUSION

Use of the published literature to better understand the epidemiology of lethal poisoning in India has clear limitations, including secular variation in publishing practices and interest in poisoning. Unfortunately, there are no long-term detailed, combination hospital and community studies from India to provide this information. In their absence, our review indicates that pesticides are the most important poison in India, with organophosphorus insecticides replacing aluminium phosphide as the key lethal poison after government regulatory changes in 2001 reduced the latter's lethality. Plant and hair dye poisoning and medicines overdose caused few deaths. Aluminium phosphide deaths mostly occurred in northern Indian states, whereas deaths from organophosphorus insecticide poisoning occurred throughout India. Paraquat poisoning has become a clinical problem in the last 10 years. Lethal pesticide poisoning remains alarmingly common, emphasising the need for additional regulatory interventions to curtail the burden of pesticide poisoning deaths in India. More detailed reporting about the specific pesticide involved in lethal poisoning will be helpful to guide regulatory decisions.

Subcutaneous injection of organophosphate (Fenitrothion)-Management of preventing the appearance of toxic symptoms: A case report

There is a risk of unnecessary extensive incision because of swelling after the subcutaneous injection; however, removing completely the injected organophosphate by making a skin incision before the appearance of toxic symptoms could reduce sequelae.

Glucocorticoid with cyclophosphamide for oral paraquat poisoning

BACKGROUND

This an update of a Cochrane Review. Paraquat is a widely used herbicide, but is also a lethal poison. In some low- and middle-income countries (LMICs) paraquat is commonly available and inexpensive, making poisoning prevention difficult. Most of the people poisoned by paraquat have taken it as a means of self-poisoning. Standard treatment for paraquat poisoning prevents further absorption and reduces the load of paraquat in the blood through haemoperfusion or haemodialysis. The effectiveness of standard treatments is extremely limited. The immune system plays an important role in exacerbating paraquat-induced lung fibrosis. Immunosuppressive treatment using glucocorticoid and cyclophosphamide in combination has been developed and studied as an intervention for paraquat poisoning.

OBJECTIVES

To assess the effects of glucocorticoid with cyclophosphamide for moderate to severe oral paraquat poisoning.

SEARCH METHODS

The most recent searches were run in September 2020. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Injuries Trials Register), Ovid MEDLINE(R), Ovid MEDLINE In-Process & Other Non-Indexed Citations, Ovid MEDLINE Daily and Ovid OLDMEDLINE, Embase Classic + Embase (Ovid), ISI WOS (SCI-EXPANDED, SSCI, CPCI-S, and CPSI-SSH), and trials registries. We also searched the following three resources: China National Knowledge Infrastructure database (CNKI ); Wanfang Data (); and VIP () on 12 November 2020. We examined the reference lists of included studies and review papers.

SELECTION CRITERIA

We included randomised controlled trials (RCTs). For this update, in accordance with Cochrane Injuries' Group policy (2015), we included only prospectively registered RCTs for trials published after 2010. We included trials which assessed the effects of glucocorticoid with cyclophosphamide delivered in combination. Eligible comparators were standard care (with or without a placebo), or any other therapy in addition to standard care. Outcomes of interest included mortality and infections.

DATA COLLECTION AND ANALYSIS

We calculated the mortality risk ratio (RR) and 95% confidence interval (CI). Where possible, we summarised data for all-cause mortality at relevant time periods (from hospital discharge to three months after discharge) in meta-analysis, using a fixed-effect model. We conducted sensitivity analyses based on factors including whether participants were assessed at baseline for plasma paraquat levels. We also reported data on infections within one week after initiation of treatment.

MAIN RESULTS

We included four trials with a total of 463 participants. The included studies were conducted in Taiwan (Republic of China), Iran, and Sri Lanka. Most participants were male. The mean age of participants was 28 years. We judged two of the four included studies, including the largest and most recently conducted study (n = 299), to be at low risk of bias for key domains including sequence generation. We assessed one study to be at high risk of selection bias and another at unclear risk, since allocation concealment was either not mentioned in the trial report or explicitly not undertaken. We assessed three of the four studies to be at unclear risk of selective reporting, as no protocols could be identified. An important source of heterogeneity amongst the included studies was the method of assessment of participants' baseline severity using analysis of plasma levels (two studies employed this method, whilst the other two did not). No studies assessed the outcome of mortality at 30 days following ingestion of paraquat. Low-certainty evidence from two studies indicates that glucocorticoids with cyclophosphamide in addition to standard care may slightly reduce the risk of death in hospital compared to standard care alone ((RR 0.82, 95% CI 0.68 to 0.99; participants = 322); results come from sensitivity analysis excluding studies not assessing plasma at baseline). However, we have limited confidence in this finding as heterogeneity was high (I2 = 77%) and studies varied in terms of size and comparators. A single large study provided data showing that there may be little or no effect of treatment at three months post discharge from hospital (RR 0.98, 95% CI 0.85 to 1.13; 1 study, 293 participants; low-certainty evidence); however, analysis of long-term results amongst participants whose injuries arose from self-poisoning must be interpreted with caution. We remain uncertain of the effect of glucocorticoids with cyclophosphamide on infection within one week after initiation of the treatment; this outcome was assessed by two small studies only (31 participants, very low-certainty evidence) that considered leukopenia as a proxy or risk factor for infection. Neither study reported infections in any participants.

AUTHORS' CONCLUSIONS

Low-certainly evidence suggests that glucocorticoids with cyclophosphamide in addition to standard care may slightly reduce mortality in hospitalised people with oral paraquat poisoning. However, we have limited confidence in this finding because of substantial heterogeneity and concerns about imprecision. Glucocorticoids with cyclophosphamide in addition to standard care may have little or no effect on mortality at three months after hospital discharge. We are uncertain whether glucocorticoid with cyclophosphamide puts patients at an increased risk of infection due to the limited evidence available for this outcome. Future research should be prospectively registered and CONSORT-compliant. Investigators should attempt to ensure an adequate sample size, screen participants for inclusion rigorously, and seek long-term follow-up of participants. Investigators may wish to research the effects of glucocorticoid in combination with other treatments.

Suicide by pesticide ingestion in Nepal and the impact of pesticide regulation

BACKGROUND

Nepal recorded 5754 suicides in 2018-19 - a high number for a relatively small country. Over 24% of these suicides were by poisoning, most by ingestion of highly concentrated agricultural pesticides. Nepal has actively regulated pesticides to reduce their health impacts since 2001. We aimed to analyse Nepal's history of pesticide regulation, pesticides responsible for poisonings, and relate them to national suicide rates.

METHODS

Information on pesticide regulation was collected from the Plant Quarantine and Pesticide Management Centre of the Ministry of Agriculture and Livestock Development. National data on suicides from 1980 to 2019 were obtained from the National Statistical Bureau and Nepal Police. Data on the pesticides responsible for self-poisoning and pesticide suicides over time were obtained from a systematic literature review.

RESULTS

As of June 2020, 171 pesticides were registered for use in Nepal, of which one was extremely hazardous (WHO Class Ia), one other highly hazardous (WHO Class Ib), and 71 moderately hazardous (WHO Class II). Twenty-four pesticides have been banned since 2001, with eight (including five WHO Class I compounds) banned in 2019. Although the suicide rate has increased more than twelve-fold since 1980, particularly for hanging (15-fold increase from 1980 to 2018), fatal pesticide self-poisoning has increased by 13-fold. Methyl-parathion is reported to be the key pesticide responsible for pesticide self-poisoning in Nepal, despite being banned in 2006.

CONCLUSION

The full effect of the recent pesticide policy reform in Nepal remains to be seen. Our analysis shows a continuing increase in suicide numbers, despite bans of the most important pesticide in 2006. This may indicate smuggling across the border and the use of the brand name (Metacid) for pesticides in general making it difficult to identify the responsible pesticide. More information is required from forensic toxicology labs that identify the individual compounds found. The effect of recent bans of common suicide pesticides needs to be monitored over the coming years. Evidence from other Asian countries suggests that HHPs bans will lead to a marked reduction in suicides, as well as fewer cases of occupational poisoning.