A study of neurologic symptoms on exposure to organophosphate pesticides in the children of agricultural workers

The relationship between pesticide exposures and primary headaches in adults: A cross-sectional study based on Rafsanjan cohort study

Objectives

Toxic substances can trigger headaches. The prevalence of pesticide use and headaches was high among the population of Rafsanjan.

Methods

A cross-sectional study was used to collect data from 9991 adults who participated via sampling people aged 35-70 years old of both genders from the Rafsanjan Cohort Study (RCS) in Iran. Demographic characteristics, habits, chronic primary headache (CPH), and episodic primary headache (EPH) were measured.

Results

The prevalence of CPH and EPH were 7.4 % and 29.9 % respectively. The multivariable model showed the odds of EPH increased significantly by the pesticide exposure on farm OR: 1.16 (1.02-1.34), in yard OR: 1.18 (1.01-1.39), duration of pesticide exposure in yard > median OR: 1.35 (1.06-1.73), at home OR: 1.31 (1.17-1.46), duration of pesticide exposure at home ≤ median OR: 1.24 (1.10-1.40) and > median OR: 1.38 (1.22-1.57). Also, pesticide preparation OR: 1.20 (1.03-1.39), duration of exposure in pesticide preparation ≤ median OR: 1.31 (1.09-1.57), and duration of exposure in managed spraying pesticide > median OR: 1.28 (1.04-1.57) increased odds of EPH. These results showed that the odds of CPH increased in participants using pesticides at home OR: 1.22 (1.02-1.48), duration of pesticide exposure at home > median OR: 1.37 (1.11-1.70), and duration of pesticide exposure in pesticide preparation > median OR: 0.47 (0.27-0.82). The odds of EPH increased with more pesticide exposures (18 %) and duration of pesticide exposure (25 %).

Conclusions

As evidenced by the obtained results, there is a relationship between pesticide exposure and headaches.

Current-use pesticide exposure pathways in Czech adults and children from the CELSPAC-SPECIMEn cohort

INTRODUCTION

In this study, we aimed to characterise exposure to pyrethroids, organophosphates, and tebuconazole through multiple pathways in 110 parent-child pairs participating in the CELSPAC-SPECIMEn study.

METHODS

First, we estimated the daily intake (EDI) of pesticides based on measured urinary metabolites. Second, we compared EDI with estimated pesticide intake from food. We used multiple linear regression to identify the main predictors of urinary pesticide concentrations. We also assessed the relationship between urinary pesticide concentrations and organic and non-organic food consumption while controlling for a range of factors. Finally, we employed a model to estimate inhalation and dermal exposure due to spray drift and volatilization after assuming pesticide application in crop fields.

RESULTS

EDI was often higher in children in comparison to adults, especially in the winter season. A comparison of food intake estimates and EDI suggested diet as a critical pathway of tebuconazole exposure, less so in the case of organophosphates. Regression models showed that consumption per g of peaches/apricots was associated with an increase of 0.37% CI [0.23% to 0.51%] in urinary tebuconazole metabolite concentrations. Consumption of white bread was associated with an increase of 0.21% CI [0.08% to 0.35%], and consumption of organic strawberries was inversely associated (-61.52% CI [-79.34% to -28.32%]), with urinary pyrethroid metabolite concentrations. Inhalation and dermal exposure seemed to represent a relatively small contribution to pesticide exposure as compared to dietary intake.

CONCLUSION

In our study population, findings indicate diet plays a significant role in exposure to the analysed pesticides. We found an influence of potential exposure due to spray drift and volatilization among the subpopulation residing near presumably sprayed crop fields to be minimal in comparison. However, the lack of data indicating actual spraying occurred during the critical 24-hour period prior to urine sample collection could be a significant contributing factor.

The Assessment of Organophosphate Pesticide Exposure among School Children in Four Regions of Thailand: Analysis of Dialkyl Phosphate Metabolites in Students' Urine and Organophosphate Pesticide Residues in Vegetables for School Lunch

In Thailand, pesticides containing organophosphates (OP) are frequently applied to crops to suppress insects. School children can be exposed to OPs on a daily basis, from food consumption to breathing and touching pesticides drifted near classrooms. Living in an agricultural area can also be one of the causes. As a result, it is important to monitor OPs residues in the food chain and biomarkers of exposure. The Gas Chromatography-Flame Photometric Detector method was employed to examine the relationship between OPs residue and DAPs (Diakly phosphate) in four targeted locations in Thailand, as well as to examine the residues of OPs in vegetable samples and DAPs in 395 school children's urine samples. Vegetables were found to contain at least one OP, with chlorpyrifos being the most prevalent. The OPs detected frequencies for Sakon Nakhon, Chiang Mai, Phang Nga, and Pathum Thani are 96.1%, 94%, 91.7%, and 83.3%, respectively. The overall centration level of OPs showed 0.3261 mg/kg, 0.0636 mg/kg, 0.0023 mg/kg, 0.0150 mg/kg, 0.2003 mg/kg, 0.0295 mg/kg, and 0.0034 mg/kg for diazinon, dimethoate, pirimiphos-methyl, chlorpyrifos, profenofos, ethion, and triazophos, respectively. Nearly 98% of school children were detected with at least one DAP. The overall level of dimethyl phosphate metabolites (5.258 µmole/mole creatinine) in urine samples is higher than diethyl phosphate metabolites (2.884 µmole/mole creatinine), especially in the case of Pathum Thani. Our findings show a consistent relationship between OPs in vegetables from wet markets and DAPs in urine samples of school children in various parts of Thailand.

A comparative study: rural versus urban children as regard exposure to organophosphorus pesticides using cholinesterase enzyme activity

Background

The uncontrolled long-term exposure to organophosphorus (OP) pesticides is hazardous to health especially in children. The present study aimed to determine the acetyl cholinesterase enzyme serum level in exposure and non-exposure children groups, to explore other clinical and laboratory outcomes of organophosphorus pesticides exposure on children living in rural versus urban areas, and to establish the hemotoxic alterations as a result of the exposure. A ninety clinically free children—forty-five from rural areas and forty-five children from urban areas—were assessed, and the clinical and laboratory effects of their exposure to organophosphorus pesticides were evaluated via measuring acetyl cholinesterase (AChE) enzyme activity.

Results

Significant differences between the two areas of residence were found in weight %, visits to the field, eating vegetables without washing, presence of insecticides at home, and previous organophosphorus pesticides toxicity of the patients and their families. Eye, respiratory, cardiac, nervous, muscle, gastrointestinal, and urinary symptoms were more common in the rural residence group which shows more exposure to pesticides. The mean level of the AChE enzyme was less in the rural residence group than the other one, and it showed significant correlations with the anemia indicating parameters. A weak positive correlation was found with platelets count.

Conclusions

Chronic organophosphorus toxicity that is more prevalent in rural areas may result in many transient neglected symptoms, unrevealed acetyl cholinesterase (AChE) enzyme deficiency, anemia, and thrombocytopenia. Acetyl cholinesterase enzyme serum level can be used as a screening test for organophosphorus pesticides exposure.

Pesticide-loaded colloidal nanodelivery systems; preparation, characterization, and applications

The fast developments in pesticide-loaded nanodelivery systems over the last decade have inspired many companies and research organizations to highlight potential applications by employing encapsulation approaches in order to protect the agricultural crops. This approach is being used to retard the indiscriminate application of conventional pesticides, as well as, to make ensure the environmental safety. This article shed light on the potential of colloidal delivery systems, particularly controlled releasing profiles of several pesticides with enhanced stability and improved solubility. Colloidal nanodelivery systems, being efficient nanoformulations, have the ability to boost up the pest-control competence for prolonged intervals thru averting the early degradation of active ingredients under severe ecofriendly circumstances. This work is thus aimed to provide critical information on the meaningful role of nanocarriers for loading of pesticides. The smart art of pesticide-loaded nanocarriers can be more fruitful owing to the use of lower amount of active ingredients with improved efficiency along with minimizing the pesticide loss. Also, the future research gaps regarding nano-pesticide formulations, such as role of nanomaterials as active ingredients are discussed briefly. In addition, this article can deliver valuable information to the readers while establishing novel pesticide-loaded nanocarriers for a wide range of applications in the agriculture sectors.

Endocrine disruptors also function as nervous disruptors and can be renamed endocrine and nervous disruptors (ENDs)

Endocrine disruption (ED) and endocrine disruptors (EDs) emerged as scientific concepts in 1995, after numerous chemical pollutants were found to be responsible for reproductive dysfunction. The World Health Organization established in the United Nations Environment Programme a list of materials, plasticizers, pesticides, and various pollutants synthesized from petrochemistry that impact not only reproduction, but also hormonal functions, directly or indirectly. Cells communicate via either chemical or electrical signals transmitted within the endocrine or nervous systems. To investigate whether hormone disruptors may also interfere directly or indirectly with the development or functioning of the nervous system through either a neuroendocrine or a more general mechanism, we examined the scientific literature to ascertain the effects of EDs on the nervous system, specifically in the categories of neurotoxicity, cognition, and behaviour. To date, we demonstrated that all of the 177 EDs identified internationally by WHO are known to have an impact on the nervous system. Furthermore, the precise mechanisms underlying this neurodisruption have also been established. It was previously believed that EDs primarily function via the thyroid. However, this study presents substantial evidence that approximately 80 % of EDs operate via other mechanisms. It thus outlines a novel concept: EDs are also neurodisruptors (NDs) and can be collectively termed endocrine and nervous disruptors (ENDs). Most of ENDs are derived from petroleum residues, and their various mechanisms of action are similar to those of "spam" in electronic communications technologies. Therefore, ENDs can be considered as an instance of spam in a biological context.

An Enzyme-Based Biosensor for the Detection of Organophosphate Compounds Using Mutant Phosphotriesterase Immobilized onto Reduced Graphene Oxide

Enzymatic detection of organophosphate (OP) compounds can be tailored using highly sensitive and selective enzymes in the development of biosensors. Previously, mutant (YT) phosphotriesterase (PTE) was reported to efficiently hydrolyze Sp and Rp enantiomers of phosphotriester. This study reports the use of phosphotriesterase mutant YT (YT-PTE) immobilized onto reduced graphene oxide (rGO) and fabricated onto a screen-printed carbon electrode (SPCE) for electrochemical detection of OP compounds. Immobilization of YT-PTE onto rGO was secured using N-hydroxysuccinimide (NHS) and N-(3-dimethylaminopropyl)-N’-ethylcarbodiimide (EDC) cross-linker, and the resulting immobilized enzyme was able to retain up to 90% of its activity. Electrochemical analysis of the SPCE/rGO/YT-PTE showed detection of paraoxon in a linear range of 1 mM–0.005 μM with its limit of detection as low as 0.11 μM. SPCE/rGO/YT-PTE exhibited high selectivity towards paraoxon and parathion and have good reproducibility. Furthermore, detection of paraoxon was also possible in a real water sample with only minor interferences.

Association of activities related to pesticide exposure on headache severity and neurodevelopment of school-children in the rural agricultural farmlands of the Western Cape of South Africa

OBJECTIVE

Children and adolescents living in agricultural areas are likely to be exposed to mixtures of pesticides during their daily activities, which may impair their neurodevelopment. We investigated various such activities in relation to headache severity and neurodevelopment of school-children living in rural agricultural areas in the Western Cape of South Africa.

METHOD

We used baseline date from 1001 school-children of the Child Health Agricultural Pesticide Cohort Study in South Africa (CapSA) aged 9-16 from seven schools and three agriculture areas in the Western Cape. Questionnaires were administrated to assess activities related to pesticide exposure and health symptoms addressing four types of activities: 1) child farm activities related to pesticide handling, 2) eating crops directly from the field, 3) contact with surface water around the field, and 4) seen and smelt pesticide spraying activities. Neurocognitive performance across three domains of attention, memory and processing speed were assessed by means of an iPad-based cognitive assessment tool, Cambridge Automated NeuroPsychological Battery (CANTAB). Headache severity was enquired using a standard Headache Impact Test (HIT-6) tool. Cross-sectional regression analysis was performed.

RESULTS

About 50% of the cohort report to have ever been engaged in activities related to pesticide exposure including farm activities, eating crops directly from the field and leisure activities. Headache severity score was consistently increased in relation to pesticide-related farm activities (score increase of 1.99; 95% CI: 0.86, 3.12), eating crops (1.52; 0.41, 2.67) and leisure activities of playing, swimming or bathing in nearby water (1.25; 0.18, 2.33). For neurocognitive outcomes, an overall negative trend with pesticide exposure-related activities was observed. Among others, involvement in pesticide-related farm activities was associated with a lower multi-tasking accuracy score (-2.74; -5.19, -0.29), while lower strategy in spatial working memory (-0.29; -0.56; -0.03) and lower paired associated learning (-0.88; -1.60, -0.17) was observed for those who pick crops off the field compared to those who do not pick crops off the field. Eating fruits directly from the vineyard or orchard was associated with a lower motor screening speed (-0.06; -0.11, -0.01) and lower rapid visual processing accuracy score (-0.02; -0.03, 0.00).

CONCLUSIONS

Children who indicate activities related to pesticide exposure may be at higher risk for developing headaches and lower cognitive performance in the domains of attention, memory and processing speed. However, self-reported data and cross-sectional design are a limitation. Future research in CapSA will consider pesticide exposure estimations via urinary biomarkers and longitudinal assessment of cognitive functions.

Systematic mapping of organophosphate contaminant (OPC) research trends between 1990 and 2018

Since the addition of polybrominated diphenyls and organochlorine pesticides (OCPs) to the world banned list, toxic organophosphate contaminants (OPCs) such as organophosphate flame retardants and organophosphate pesticides have been, respectively, used as substitutes. These chemicals are reported to be more toxic than their halogenated counterparts. It is rare to find a study that focuses on visualising the publication trends of these chemical classes. In this study, we employed a bibliometric model to systematically map research activities between 1990 and 2018 using OPC articles retrieved from the WoS and Scopus databases. A total of 1090 articles were retrieved from the hybrid databases with an article/author and author/article ratio of 0.33 and 3.02, respectively. Articles on OPC studies were positively correlated with the number of years (r² = 0.96; y = 0.23x² - 3.82x + 27.90) suggesting an increase in the number of articles on this subject in future. The USA ranked first in terms of articles (n = 245) and citations (n = 12,922) followed by China and India (203 and 89 articles, respectively). Articles from China and the USA had strong collaboration with other countries. Research priorities and top author keywords included pesticides (n = 112), organophosphate (n = 83) and acetylcholinesterase (n = 60) and were also well represented in keywords-plus. Developed countries had higher outputs compared to developing countries. It was observed that from our thematic literature classifications, human toxicity, ecotoxicological impacts, and environmental monitoring of OPCs were of greater importance to scholars, thus indicating the direction of future research. Futuristic studies need to foster partnership with policymakers, journalists, consultants, farmers, artisans and community workers on OPC research. This will not only enhance scientific communication and community engagement but will also increase the awareness of these pollutants to the general public.

In Vitro Evaluation of Neutral Aryloximes as Reactivators for Electrophorus eel Acetylcholinesterase Inhibited by Paraoxon

Casualties caused by organophosphorus pesticides are a burden for health systems in developing and poor countries. Such compounds are potent acetylcholinesterase irreversible inhibitors, and share the toxic profile with nerve agents. Pyridinium oximes are the only clinically available antidotes against poisoning by these substances, but their poor penetration into the blood-brain barrier hampers the efficient enzyme reactivation at the central nervous system. In searching for structural factors that may be explored in future SAR studies, we evaluated neutral aryloximes as reactivators for paraoxon-inhibited Electrophorus eel acetylcholinesterase. Our findings may result into lead compounds, useful for development of more active compounds for emergencies and supportive care.

Retrograde activation of CB1R by muscarinic receptors protects against central organophosphorus toxicity

The acute toxicity of organophosphorus-based compounds is primarily a result of acetylcholinesterase inhibition in the central and peripheral nervous systems. The resulting cholinergic crisis manifests as seizure, paralysis, respiratory failure and neurotoxicity. Though overstimulation of muscarinic receptors is the mechanistic basis of central organophosphorus (OP) toxicities, short-term changes in synapse physiology that precede OP-induced seizures have not been investigated in detail. To study acute effects of OP exposure on synaptic function, field excitatory postsynaptic potentials (fEPSPs) were recorded from Schaffer collateral synapses in the mouse hippocampus CA1 stratum radiatum during perfusion with various OP compounds. Administration of the OPs paraoxon, soman or VX rapidly and stably depressed fEPSPs via a presynaptic mechanism, while the non-OP proconvulsant tetramethylenedisulfotetramine had no effect on fEPSP amplitudes. OP-induced presynaptic long-term depression manifested prior to interictal spiking, occurred independent of recurrent firing, and did not require NMDA receptor currents, suggesting that it was not mediated by activity-dependent calcium uptake. Pharmacological dissection revealed that the presynaptic endocannabinoid type 1 receptor (CB1R) as well as postsynaptic M₁ and M₃ muscarinic acetylcholine receptors were necessary for OP-LTD. Administration of CB1R antagonists significantly reduced survival in mice after a soman challenge, revealing an acute protective role for endogenous CB1R signaling during OP exposure. Collectively these data demonstrate that the endocannabinoid system alters glutamatergic synaptic function during the acute response to OP acetylcholinesterase inhibitors.

Rice pest management with reduced risk pesticides in India

Sitapur district in the Uttar Pradesh (U.P.) state of northern India has been observed to consume large amounts of WHO classified "extremely" and "highly hazardous" pesticides, in rice crop, posing significant health and environmental threats. Keeping in view this problem, integrated pest management (IPM) modules were synthesized for rice crop and then compared with non-IPM/farmer's practice (NIPM). This study assisted in identifying pesticides with reduced risk to the environment. To measure and compare risks, environmental impact quotient (EIQ) has been used as a pesticide risk indicator model, between IPM and NIPM programs. Using this model, the field EIQ values (EIQ field use rating or EIQ-FUR), for 32 commonly used pesticides in the region, were evaluated based on dosage, frequency, and percent active ingredients present in the pesticide formulations. The results conclude that copper oxychloride (CuOCl₂) (50 WP at 1.25 kg/ha) and mancozeb (75 WP at 1.25 kg/ha) were the most detrimental to arthropod parasitoids and were the highest contributors to environmental risk (13-16%), in rice crop. This is based on the comparison of total dosage and active ingredients of pesticides applied under IPM and NIPM, with the total field EIQ values. The IPM modules were observed to have least impact on natural enemies with 30-40% increase in population, while keeping the weed population below 10%. NIPM, on the other hand, had resulted in 20% reduction in crop yields, 50% reduction in biodiversity, and about 150% increase in weed population, relative to the control (untreated) rice fields. Moreover, NIPM practices had been observed to pose 56% greater risk as per the total field EIQ values (62 for IPM and 141 for NIPM). The observations concluded that the EIQ model is a useful tool and can be easily used by the pesticide managers for assessing the risk against NIPM.

Neuropsychiatric Disorders in Farmers Associated with Organophosphorus Pesticide Exposure in a Rural Village of Northwest México

This study aims to determine the degree of acetylcholinesterase inhibition and neurological symptoms for each of the psychiatric disorders diagnosed in the farm workers of a rural population in the state of Baja California, Mexico. We conducted a cross-sectional study on 140 agricultural workers (exposed participants). The study was run using the Mini International Neuropsychiatric Interview Diagnostic Test (MINI), a pre-established questionnaire to diagnose the mental state of each agricultural worker. Analysis of enzymatic activity was carried out using the modified Ellman method. The results showed that, among agricultural workers with slightly inhibited enzymatic activity, 25% met the criteria for the diagnosis of major depression with suicidal attitudes, 23.9% with inhibited enzymatic activity showed generalized anxiety, 23.5% showed combined depression⁻anxiety, and 22% met the criteria for major depression and no psychiatric diagnosis disorder. These results suggest the need for the development of effective public-health strategies to inform farm workers about integrated pesticide management in order to prevent serious health complications.

Pesticides as the drivers of neuropsychotic diseases, cancers, and teratogenicity among agro-workers as well as general public

The need to maximize agricultural productivity has made pesticides an indispensable part of current times. Farmers are unaware of the lurking consequences of the pesticide exposure, which endanger their health. It also puts the unsuspecting consumers in peril. The pesticides (from organophosphates, organochlorine, and carbamate class) disrupt the immune and hormonal signaling, causing recurrent inflammation, which leads to a wide array pathologies, including teratogenicity. Numerous farmers have fallen victim to neural disorders-driven suicides and lungs, prostate/breast cancer-caused untimely deaths. Green revolution which significantly escalated agricultural productivity is backfiring now. It is high time that environmental and agricultural authorities act to restrain the excessive usage of the detrimental chemicals and educate farmers regarding the crisis. This review discusses the biological mechanisms of pesticide-driven pathogenesis (such as the activation or inhibition of caspase, serine protease, acetylcholinesterase) and presents the pesticide-exposure-caused health deterioration in USA, India, and Africa. This holistic and critical review should be an eye-opener for general public, and a guide for researchers.

Superior efficacy of HI-6 dimethanesulfonate over pralidoxime methylsulfate against Russian VX poisoning in cynomolgus monkeys (Macaca fascicularis)

Organophosphorus nerve agents still represent a serious risk to human health. In the French armed forces, the current emergency treatment against OP intoxications is a fully licensed wet-dry dual-chambered autoinjector (Ineurope ®), that contains pralidoxime methylsulfate (2-PAM) to reactivate inhibited acetylcholinesterase (AChE), atropine sulfate (AS) and avizafone chlorhydrate (AVZ). While this treatment is effective against several of the known nerve agents, it shows little efficacy against the Russian VX (VR), one of the most toxic compounds. HI-6 dimethanesulfonate (HI-6 DMS) is an oxime able to reactivate in vitro and in vivo VR-inhibited AChE. To confirm the superiority of HI-6 DMS towards 2-PAM prior to licensing, we compared the two 3-drug-combinations (HI-6 vs 2-PAM, 33 and 18 mg/kg respectively, equimolar doses; AS/AVZ 0.25/0.175 mg/kg respectively) in VR-poisoned cynomolgus macaques, the model required by the French drug regulatory agency. In parallel we performed HI-6 pharmacokinetics analysis using a one compartment model. A better efficacy of the HI-6 DMS combination was clearly observed: up to 5 LD₅₀ of VR (i.m.), a single administration of the HI-6 DMS combination, shortly after the onset of clinical signs, prevented death of the four intoxicated animals. Conversely 2-PAM only prevented death in one out of three subjects exposed to the same amount of VR. As expected with V agents, reinhibition of blood AChE was observed but without any apparent impact on the clinical recovery of the animals. A single administration of the HI-6 DMS combination was still but partially effective at 15 LD₅₀ of VR, allowing a 50% survival rate.

Neurobehavioural symptoms and acute pesticide poisoning: a cross-sectional study among male pesticide applicators selected from three commercial farming systems in Ethiopia

OBJECTIVE

To estimate prevalence of acute pesticide poisoning (APP) and its association with neurobehavioural symptoms in Ethiopian pesticide applicators.

METHODS

We performed a cross-sectional survey among 256 pesticide applicators from small-scale irrigated farms, a large-scale open farm and large-scale greenhouses. APP was ascertained using a modified WHO case definition, and neurobehavioural symptoms were collected with a standardised questionnaire (Q16). Exposure to pesticides was estimated using detailed exposure algorithms specifically developed for Ethiopian farms. Multiple logistic regression models were used to estimate risk of APP and its association with neurobehavioural symptoms.

RESULTS

Overall APP prevalence was 16%. Working as an applicator in greenhouses was strongly associated with APP (OR 3.00, 95% CI 1.38 to 6.54). Estimated annual pesticide exposure was also associated with APP (OR 1.14, 95% CI 1.00 to 1.20). Longer duration of employment appeared to be negatively associated with APP. Having had an APP was strongly associated with reporting more neurobehavioural symptoms (OR 2.15, 95% CI 1.01 to 4.58) independent of cumulative pesticide exposure. Cumulative exposure to pesticides appeared to be associated with neurobehavioural symptoms among applicators without and with APP.

CONCLUSIONS

We showed a substantial prevalence of APP that differed between farming systems and was strongly associated with neurobehavioural symptoms. Intensity of exposure was also clearly associated with these symptoms. Reduction and control of occupational exposure to pesticides is urgently needed in Ethiopia.

Molecular detection of M. tuberculosis and M. bovis and hematological and biochemical analyses in agricultural sprayers exposed to pesticides: A cross-sectional study in Punjab, Pakistan during 2014-2016

We determined the correlation between a pesticide exposure, physical health and susceptibility toward tuberculosis along with hematological indices and liver enzymes' alterations in sprayers exposed to pesticides. Molecular detection of Mycobacterium tuberculosis and Mycobacterium bovis was detected by targeting histone-like protein (hupB) gene. The WBC (white blood cells) and RBC (red blood cells) levels of male sprayers and non-sprayers were significantly different (P<0.05). In female spray workers, the WBC and neutrophils levels were significantly different as compared with non-sprayers. Overall, in both male and female pesticide-exposed sprayers, mean values of alanine amino transferase and aspartate amino transferase were higher as compared with unexposed workers. M. Tuberculosis were detected in 15% male sprayers and 36% female sprayers while, M. bovis was detected in 5% male sprayers and 10% female sprayers. A χ²-test indicated that there existed a significant different (P<0.05) between positive and negative M. tuberculosis and M. bovis in both male/female spray workers out of total. The susceptibility of pesticide-exposed sprayers to tuberculosis and alterations in hematology and liver enzymes is crucial for health. Toxic effects of pesticides may lead to a weak immune system and increased tuberculosis susceptibility.

A retrospective study on non-drug related poisoning in the community among children from south India

OBJECTIVES

This retrospective study was performed to determine the incidence, demographic distribution, types and outcomes across various non-drug related poisonings among children attending a tertiary care center in south India.

METHODS

All children from 0-16 years who presented to the Paediatric Emergency Department, Christian Medical College, Vellore with non-drug related poisoning from October 2004 to September 2013 were included.

RESULTS

Out of the total 997 cases of poisoning, 629 (63.1%) cases were contributed by chemicals and plants: mainly hydrocarbons (kerosene) 309 (49.1%); organophosphates 72 (11.5%); corrosive acids and alkalis 57 (9.1%); insecticides 51 (8.1%); and plant poisons 20 (3.2%). Males (62.79%) and children < 5 years (77.42%) were mostly affected. Although many children developed complications requiring intensive care unit admissions, the total mortality was only 9 (1.4%). The incidence of poisoning showed a decreasing trend over the last 4 years.

CONCLUSION

This study for the first time gives an elaborative insight on non-drug related pediatric poisoning from a tertiary care center in south India for almost a decade.

Association of Long-Term Pesticide Exposure and Biologic Parameters in Female Farm Workers in Tanzania: A Cross Sectional Study

The study aimed to assess the association of long-term pesticide exposure (≥5 years) with hematological, serum biochemical parameters and acetylcholinesterase activity in farm workers. These pesticides included organophosphorus pesticides, carbamates, pyrethroids, dithiocarbamates, and other pesticides such as endosulfan. Applying a cross-sectional study design, 69 females from a pesticide-exposed farm population and 30 females from a district not using pesticides (reference group) were studied. The mean red cell corpuscular volume and hematocrit values were significantly lower (74.7 ± 9.1 fl; 95% CI 72.5-76.9 and 32.0% ± 4.6%; 95% CI 30.9-33.1, respectively) in the exposed compared to the reference group, whereas mean corpuscular hemoglobin concentration and platelets were significantly higher (37.4 ± 3.8 g/dL; 95% CI 36.5-38.3 and 374.1 ± 95.3/L; 95% CI 351.2-396.9, respectively) in the exposed compared to the reference group. Mean serum glutamic oxaloacetate transaminase (20.7 ± 8.9 U/L; 95% CI 18.5-22.9) and creatinine (83.9 ± 6.6 μmol/L; 95% CI 82.3-85.5) were significantly higher in the exposed compared to the reference group. A higher mean esterase activity (AChE 0.6 ± 0.2 mM/min/mg protein; 95% CI 0.56-0.7; BChE 0.9 ± 0.4 mM/min/mg protein; 95% CI 0.9-1.1) was noted in the exposed group. Regression models suggest that occupational exposure (p < 0.001) could be a predictor of esterase (AChE and BChE) activity and biochemical changes (β = 0.4, 95% CI: 0.3-0.5; β = 0.7, 95% CI: 0.6-0.9, respectively). Long-term pesticide exposure affects the hemato-biochemical and esterase responses, establishing the need for further studies.

Mitigation of diazinon-induced cardiovascular and renal dysfunction by gallic acid

Studies of the link between environmental pollutants and cardiovascular dysfunction, neglected for decades, have recently provided new insights into the pathology and consequences of these killers. In this study, rats were divided into four groups, each containing 10 rats. The rats in group one served as controls and were administered normal saline, whereas the rats in group two were orally gavaged with 3 mg/kg of diazinon (DZN) alone for twenty one consecutive days. The rats in groups 3 and 4 were administered respective 60 mg/kg and 120 mg/kg gallic acid (GA) in addition to DZN for twenty one consecutive days. Exposure of rats to diazinon significantly (p<0.05) reduced the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and reduced glutathione (GSH) content. Malondialdehyde, hydrogen peroxide (H2O2) and nitric oxide (NO) contents were also significantly (p<0.05) elevated following DZN exposure. DZN further caused a significant (p<0.05) decrease of heart rate and QT interval prolongation. Hematologic analysis revealed significant reduction (p<0.05) in packed cell volume (PCV), hemoglobin concentration (Hb), red blood cell (RBC) count, and total white blood cell count of rats administered only DZN. Observations in this study suggest a modulatory role of gallic acid in diazinon-induced anemia and associated cardiovascular dysfunction in rats. Treatment with gallic acid reversed the oxidative stress markers studied, increased the antioxidant defence system and reduced deleterious effects on hematological parameters in rats. Pathologic findings of the heart and kidney were also found to be lessened.

Delayed Effects of Transcutaneous Organophosphate Poisoning in Four Children

Contamination or transcutaneous absorption of organophosphates (OP) is rare and there exist only few reports of such manner of poisoning. We report four children from the same family in whom temporal proximity of the disease onset, a detailed interrogation of parents and exclusion of other clinical differentials, led to the diagnosis of transcutaneous intoxication with organophosphates (diazinon). The contamination occurred during the game with a freshly used poison can. Uncommon clinical picture was marked by delayed signs predominantly reflecting certain nicotinic effects (muscle weakness, cramps) along with subtle neuropathic features occurring throughout a few weeks after initial event. Our illustrative cases can further contribute to the better awareness and understanding of variable spectrum of transcutaneous route of OP poisoning.

A systematic review of the influence of occupational organophosphate pesticides exposure on neurological impairment

OBJECTIVE

The aim of this study was to conduct a systematic review of the published literature and to estimate whether or not there is a causal relationship between occupational exposure to organophosphate pesticides (OPs) and either neurological impairment or depressive symptoms.

DATA SOURCES

EMBASE, MEDLINE, Global Health and PsycINFO (1980 to April 2014).

SETTING

Observational studies (cross-sectional, cohort and case-control studies) with exposed and unexposed groups.

PARTICIPANTS

People who occupationally use OPs for more than 1 month and their family.

PRIMARY OUTCOME

Results of neurological core test batteries or depressive symptoms such as headaches, anxiety and dizziness.

STUDY APPRAISAL AND SYNTHESIS METHODS

After an extensive search of various literature databases, one author screened titles and abstracts, searched the relevant publications manually and conducted data extraction. All extracted data from the selected articles were synthesised for analysis. Quality appraisal was conducted using the Newcastle Ottawa Scale.

RESULTS

Of the 1024 articles retrieved by database search, 24 studies that met the inclusion and exclusion criteria were selected for analysis. Of the selected studies, 17 were cross-sectional and the remaining 7 were cohort and nested case-control studies. The geographical areas included in the studies were the USA (10 studies), the UK (4 studies), Africa (4 studies), Asia (3 studies), Europe (2 studies) and South America (1 study). Each of the included studies used different exposure and outcome assessments such as neurological scores and depressive symptoms, making it difficult to compare the results exactly. Most studies showed that exposed groups had poorer results than unexposed groups; however, owing to the inconsistent neurological test batteries, there was not enough pooling evidence to conduct a meta-analysis.

CONCLUSIONS

The findings of this literature review indicate that it is necessary to standardise the neurological or neuropsychological test battery and methods of measuring exposure to OPs.

Longitudinal assessment of chlorpyrifos exposure and self-reported neurological symptoms in adolescent pesticide applicators

OBJECTIVES

Occupational exposure of organophosphorus pesticides, such as chlorpyrifos (CPF), in adolescents is of particular concern because of the potential vulnerability of the developing neurological system. The objectives of this study were to examine how neurological symptoms reported over the application season vary across time, whether these effects are reversible postapplication and if there are associations between CPF biomarkers and neurological symptoms in an adolescent study population.

SETTING

The longitudinal study was conducted in two agricultural districts of Menoufia Governorate, Egypt between April 2010 and January 2011.

PARTICIPANTS

Male adolescent participants, including CPF applicators (n=57) and non-applicators (n=38), were recruited.

PRIMARY AND SECONDARY OUTCOME MEASURES

Self-reported data for 25 neurological symptoms were collected at 32 time points over the 8-month period before, during and after the application season. Additionally, urine and blood samples were collected to measure urine trichloro-2-pyridinol (TCPy), a CPF-specific biomarker and blood cholinesterase activity.

RESULTS

Applicators and non-applicators report the highest numbers of symptoms during the application season, followed by a reduction in symptoms after the application ended. Applicators reported a greater percentage of neurological symptoms, relative to baseline, than non-applicators after accounting for potential covariates. Among the applicators, cumulative TCPy was positively and significantly associated with the average percentage of symptoms (B=4.56, 95% CI 3.29 to 5.84; p<0.001). Significant associations (p=0.03-0.07) between the change in butyrylcholinesterase activity from the preapplication to the postapplication season and several domains of neurological symptoms were also found, even after adjusting for potential covariates.

CONCLUSIONS

These observations demonstrate changes in the reporting of symptoms across the application season, showing an increase in symptom reporting during application and recovery following the end of pesticide application. These findings reinforce the growing concern regarding the neurotoxic health effects of CPF in adolescent applicators in developing countries and the need for developing and implementing intervention programmes.

Longitudinal assessment of chlorpyrifos exposure and self-reported neurological symptoms in adolescent pesticide applicators

OBJECTIVES

Occupational exposure of organophosphorus pesticides, such as chlorpyrifos (CPF), in adolescents is of particular concern because of the potential vulnerability of the developing neurological system. The objectives of this study were to examine how neurological symptoms reported over the application season vary across time, whether these effects are reversible postapplication and if there are associations between CPF biomarkers and neurological symptoms in an adolescent study population.

SETTING

The longitudinal study was conducted in two agricultural districts of Menoufia Governorate, Egypt between April 2010 and January 2011.

PARTICIPANTS

Male adolescent participants, including CPF applicators (n=57) and non-applicators (n=38), were recruited.

PRIMARY AND SECONDARY OUTCOME MEASURES

Self-reported data for 25 neurological symptoms were collected at 32 time points over the 8-month period before, during and after the application season. Additionally, urine and blood samples were collected to measure urine trichloro-2-pyridinol (TCPy), a CPF-specific biomarker and blood cholinesterase activity.

RESULTS

Applicators and non-applicators report the highest numbers of symptoms during the application season, followed by a reduction in symptoms after the application ended. Applicators reported a greater percentage of neurological symptoms, relative to baseline, than non-applicators after accounting for potential covariates. Among the applicators, cumulative TCPy was positively and significantly associated with the average percentage of symptoms (B=4.56, 95% CI 3.29 to 5.84; p<0.001). Significant associations (p=0.03-0.07) between the change in butyrylcholinesterase activity from the preapplication to the postapplication season and several domains of neurological symptoms were also found, even after adjusting for potential covariates.

CONCLUSIONS

These observations demonstrate changes in the reporting of symptoms across the application season, showing an increase in symptom reporting during application and recovery following the end of pesticide application. These findings reinforce the growing concern regarding the neurotoxic health effects of CPF in adolescent applicators in developing countries and the need for developing and implementing intervention programmes.

Health aspects of organophosphorous pesticides in asian countries

Organophosphorous (OP) pesticides are used frequently in agriculture, particularly in Asian countries over the past decades. Poisoning by these agents, either as acute or chronic in these nations, is a serious health problem. OP pesticides residue in fruits and vegetables that may not induce early clinical features, could also affect the human health. Therefore, medical and health professionals should be aware and learn more on the toxicology, prevention and proper management of OP poisoning. The well-known mechanism of OP toxicity is the inhibition of acetyl cholinesterase, resulting in an accumulation of acetylcholine and continued stimulation of acetylcholine receptors. Therefore, they are also called anticholinesterase agents. Determination of blood acetyl cholinesterase and butyryl cholinesterase activities remains a mainstay for the rapid initial screening of OP pesticides. Quantitative analysis of OP and their degradation products in plasma and urine by mass spectrometric methods is a more specific method, but is expensive and limited to specialized laboratories. Therefore, history of OP pesticides exposure and clinical manifestations of a cholinergic syndrome is sufficient for management of the exposed patients. However, electrophysiological tests may be required for the diagnosis of delayed neuropathy of OP poisoning. The standard management of OP poisoning includes decontamination, atropine sulphate with an oxime. Recent advances focus on blood alkalinisation and magnesium sulphate as promising adjunctive therapies. Preventive measures in OP exposure are of great importance in human health in developing countries. Therefore, regulations and controls on safe use of OP particularly in Asian countries are recommended.

Recent advances in the treatment of organophosphorous poisonings

Organophosphorous compounds have been employed as pesticides and chemical warfare nerve agents. Toxicity of organophosphorous compounds is a result of excessive cholinergic stimulation through inhibition of acetyl cholinesterase. Clinical manifestations include cholinergic syndromes, central nervous system and cardiovascular disorders. Organophosphorous pesticide poisonings are common in developing worlds including Iran and Sri Lanka. Nerve agents were used during the Iraq-Iran war in 1983-1988 and in a terrorist attack in Japan in 1994-1995. Following decontamination, depending on the severity of intoxication the administration of atropine to counteract muscarinic over-stimulation, and an oxime to reactivate acetyl cholinesterase are indicated. Supportive and intensive care therapy including diazepam to control convulsions and mechanical respiration may be required. Recent investigations have revealed that intravenous infusion of sodium bicarbonate to produce mild to moderate alkalinization is effective. Gacyclidine; an antiglutamatergic compound, was also proved to be beneficial in conjunction with atropine, pralidoxime, and diazepam in nerve agent poisoning. Intravenous magnesium sulfate decreased hospitalization duration and improved outcomes in patients with organophosphorous poisoning. Bio-scavengers including fresh frozen plasma or albumin have recently been suggested as a useful therapy through clearing of free organophosphates. Hemofiltration and antioxidants are also suggested for organophosphorous poisoning. Recombinant bacterial phosphotriesterases and hydrolases that are able to transfer organophosphorous-degrading enzymes are very promising in delayed treatment of organophosphorous poisoning. Recently, encapsulation of drugs or enzymes in nanocarriers has also been proposed. Given the signs and symptoms of organophosphorous poisoning, health professionals should remain updated about the recent advances in treatment of organophosphorous poisoning poisonings.