Forensic toxicological and analytical aspects of carbamate poisoning - A review.

Pesticides play a pivotal role in modern agricultural practices and effective domestic pest control. Despite their advantages, pesticides pose a great danger to humans and animals due to their toxicity. Pesticides, particularly carbamates, are extensively used all over the world in crop protection and domestic pest control, however, also causing morbidity and mortality on a larger scale, which is of great significance in both clinical and criminal justice management.Carbamates are derived from a carbamic acid (NH2COOH) that are commonly used as insecticides. Ethienocarb, Sevin, Carbaryl, Fenoxycarb, Furadan, Carbofuran, Aldicarb, and 2-(1-Methylpropyl) phenyl N-methylcarbamate are examples of insecticides that include the carbamate functional group. By reversibly inactivating the enzyme acetylcholinesterase, these insecticides can induce cholinesterase inhibition poisoning.Chromatographic methods, notably gas and liquid chromatography have traditionally been employed to analyse carbamate pesticides and their metabolites in various matrices. These approaches are employed due to their ability to separate the chemicals contained in a sample; as well as identify and quantify these compounds utilizing advanced detection systems. Aside from these GC and LC conventional methods, other detection and/or hyphenated techniques such as single-quadrupole, ion-trap, triple-quadrupole, or tandem mass spectrometry, have been used in carbamate analysis to provide quick results with excellent sensitivity, precision, and accuracy.The objective of this review is to describe various analytical techniques used to detect and determine carbamate pesticides in various matrices which include urine, blood, and tissues that are commonly encountered in emergency hospital laboratories and forensic science laboratories.

Intentional Carbofuran poisoning in 7 dogs.

BACKGROUND: Carbofuran is a widely used broad-spectrum pesticide that, despite strict regulation and being banned for more than a decade, is still encountered in cases of intentional poisoning in dogs and wildlife. The objective of the study was to provide a complete and detailed description of the pathological, histological and toxicological findings of 7 cases of intentional carbofuran poisoning in dogs. RESULTS: In this retrospective study, 7 cases of carbofuran intoxication recorded from July 2015 to June 2017 were analyzed. Following complete history recording, all cases were examined by complete necropsy and histopathology. Carbofuran intoxication was confirmed in all cases by gas chromatography. The postmortem examination revealed extensive hemorrhaging and congestion located mainly within the respiratory, nervous and cardiovascular systems, accompanied by degeneration and necrosis within the lungs, heart, and kidneys. CONCLUSIONS: Although carbamates have been banned in the European Union, carbamate poisoning is still frequently encountered, especially in wild animals. This paper will contribute to a better understanding of the occurrence and pathogenesis of acute carbofuran exposure in dogs and contribute some peculiar pathological features of this type of poisoning to the current literature.

[Investigation of acute poisoning event caused by carbofuran].

Objective: To analyze the epidemiological characteristics and response process of an acute poisoning event caused by carbofuran in buttered tea and provide scientific evidence for the investigation of similar events in the future. Methods: Field epidemiological survey, animal experiments and laboratory tests were conducted for an acute poisoning event occurred in Suopo township of Danba county of Sichuan province in 2018. Descriptive epidemiological method was used to analyze the epidemiological characteristics of the acute poisoning event. Results: A total of 26 poisoning cases occurred in 3 villages. The total attack rate was 41.27%. No death cases were reported. The 26 cases occurred in a few minutes after drinking buttered tea, the main symptoms were vomit, dizziness, miosis and nausea. A dog showed the same symptoms after drinking a sample of buttered tea. Carbofuran was detected in buttered tea, vomitus and zanba samples. Conclusions: The acute poisoning was caused by carbofuran in buttered tea, the transmission mode was point source spread. Effective epidemiological investigation and simple animal experiment can provide evidence for the rapid sample detection and clinical treatment of cases in emergency response. Timely case treatment and strict poisoning source control are the key measures to reduce casualty and prevent the spread of poisoning.

Exhumation of Wistar rats experimentally exposed to the carbamate pesticides aldicarb and carbofuran: A pathological and toxicological study.

Exhumation is required for the investigation of suspicions deaths when a body is buried and is usually performed under court order. Exhumation of animals is not a routine practice in forensic pathology. In this study, 30 male 70-day-old Wistar rats were experimentally exposed to the carbamate pesticides aldicarb and carbofuran. Toxicological, macroscopic and microscopic examinations were performed. Groups of 3 animals (2 exposed and 1 control) were evaluated at 24h, 3days, 5days, 7days and 10days post-mortem. In histopathological examination, the brain, liver, lungs and kidneys were assessed, and for toxicological analysis, the gastric contents, liver, vitreous humor, skeletal muscle and larvae (when available) were collected. The pesticides were detected by HPLC and quantified in the analyzed matrices, and a possible delay in tissue putrefaction due to the pesticides was observed. This study has revealed that it is possible to exhume animals for investigations of possible poisoning by carbamates and has demonstrated that the exhumation of an animal in a suspected case of poisoning should not be ruled out. The increasing demand for investigations of suspicious animal deaths, e.g., in cases of poisoning, will likely lead to an increase in the use of this type of procedure in veterinary pathology.

Poisoning of cats and dogs by the carbamate pesticides aldicarb and carbofuran.

The intentional and accidental poisoning of animals and people is a threat to public health and safety worldwide. Necropsies and histopathological examinations of 26 cats and 10 dogs poisoned by the carbamates aldicarb and carbofuran, confirmed by thin layer chromatography (TLC) and high performance liquid chromatography with diode-array detector (HPLC-DAD) were analysed, with variable post mortem interval and conservation of the carcass. Biological matrices were collected for toxicological and histopathological analyses. High performance liquid chromatography with diode-array detector (HPLC-DAD) was utilized to detect aldicarb and its metabolites, aldicarb sulphoxide and aldicarb sulphone, and carbofuran. The variable post mortem interval and the method of conservation of the carcass may be harmful to toxicological, necroscopic and histopathological analyses, that should be performed in order to provide reliable evidences to investigate possible poisoning of animals, which is cruel crime, and are usually linked to domestic or social conflict.

OCCUPATIONAL CARBAMATE POISONING IN THAILAND.

Carbamate insecticide is a leading cause of poisoning in Thailand. The objective of this study was to characterize the clinical manifestations and modes of occupational exposure in carbamate poisoning cases. We retrospectively studied all the cases of carbamate poisoning due to occupational exposure recorded in the Ramathibodi Poison Center Toxic Exposure Surveillance system during 2005 to 2010. Demographic data, clinical manifestations and severity were analyzed statistically. During the study period, 3,183 cases were identified, of which 170 (5.3%) were deemed to be due to occupational exposure. Ninety-six cases (56.5%) and 35 cases (20.6%) were poisoned by carbofuran and methomyl, respectively. Carbofuran is sold as a 3% grain and applied by sowing; methomyl is sold as a liquid and is applied by spraying. The majority of poisoned patients did not wear personal protective equipment (PPE) while applying the carbamates. The clinical manifestations of occupational carbofuran poisoning recorded were nausea and vomiting (82.3%), headaches (56.3%) and miosis (19.8%). The clinical manifestations of methomyl poisoning were nausea and vomiting (74.3%), headaches (57.1%) and palpitations (11.4%). Most patients in both groups had mild symptoms. Only one case in each group required endotracheal intubation and mechanical ventilation support. There were no deaths and the lengths of hospitalization ranged from 2 hours to 2 days. Occupational carbamate poisoning cases in our series were mostly mild and the patients recovered quickly. There were only rare cases of serious symptoms. Lack of knowledge and inadequate PPE were the major factors contributing to occupational poisoning. Educating agricultural workers about correct precautions and pesticide use could minimize this type of poisoning.

Confirmed organophosphorus and carbamate pesticide poisonings in South African wildlife (2009-2014).

During a six-year period (from January 2009 to December 2014), specimens collected from 344 cases of suspected organophosphorus and carbamate pesticide poisonings in wildlife, including birds, were submitted to the Toxicology Laboratory (ARC-OVI) for analysis. A positive diagnosis was made in 135 (39%) of these cases. The majority of cases were from birds, which included Cape vultures (Gyps coprotheres) and African white-backed vultures (Gyps africanus) and bateleur eagles (Terathopius ecaudatus). In one incident 49 vultures were killed when a farmer intentionally laced carcasses with carbofuran in an attempt to control jackal predation. There were 22 incidents of poisoning in helmeted guineafowl (Numida meleagris). On nine different occasions blue cranes (Anthropoides paradiseus) were poisoned, in one incident 14 birds were reported to have been killed. Over the period of investigation, there were 20 cases of poisoning involving mammalian species, the majority being vervet monkeys (Chlorocebus pygerythrus). The carbamate pesticides were responsible for 57 incidents of poisoning. Aldicarb, carbofuran and methomyl were detected in 26, 18 and 12 cases respectively. The majority of organophosphorus pesticide poisonings were caused by diazinon (n = 19), monocrotophos (n = 13) and methamidophos (n = 10).

[Determination of carbofuran in the biological material for the purpose of forensic medical examination].

It is proposed to use the mixture of acetone and ethylacetate (1:1) as an universal solvent for the extraction of carbofuran from cadaveric tissues and fluids. Extracted carbufuran can be purified from endogenous admixtures on KSS No 3 Silica Gel columns (80/120 mcm) and identified using TLC, electron spectrophotometrty, HPLC, and GC-MS. The proposed method of forensic chemical analysis of carbofuran was applied for the purpose of forensic medical expertise.

Carbofuran concentrations in blood, bile and tissues in fatal cases of homicide and suicide.

Carbofuran is a broad spectrum carbamate insecticide which inhibits cholinesterase. In the recent past several carbofuran related homicide and suicide cases were reported in Sri Lanka. The concentration of carbofuran found in blood, bile and/or tissues in eight fatal cases were presented in this paper. Liquid-liquid extraction with chloroform was carried out with tissue and beverage samples while blood and bile samples were roller mixed with n-hexane and finally extracted into acetonitrile. Qualitative analysis of carbofuran in biological specimens was carried out using TLC and GC-MS. Presence of carbofuran and its metabolite carbofuran phenol were confirmed by GC-MS. The quantitative analysis was carried out using a validated method where Zorbax Eclips XDB C18 column was used in HPLC with photo diode array detector and GC-MS. In blood, bile, liver and stomach contents/stomach and contents both carbofuran and carbofuran phenol were identified, while in certain cases only the metabolite, carbofuran phenol was identified in blood. The carbofuran levels ranged from 0.4 to 18 µg/ml in blood, 0.4 to 60 µg/ml in bile, 2.2 µg/g in liver and 0.3 to 300 µg/g in stomach contents/stomach and contents.

Poisoning by illegal rodenticides containing acetylcholinesterase inhibitors (chumbinho): a prospective case series.

OBJECTIVE: To describe a prospective case series of poisonings caused by ingestion of illegal rodenticides containing acetylcholinesterase inhibitors, mainly "chumbinho," followed-up by the Campinas PCC for a period of 1 year. CASE SERIES: Seventy-six cases were included, of which 53.9% were males. Age ranged from 2 to 74 years (median = 36 years). The main circumstances leading to poisoning were intentional (suicide attempts 92.1%; homicide attempts 5.3%), and 65.8% were admitted less than 2 hours after ingestion. Most of the patients (96.1%) showed cholinergic muscarinic manifestations, particularly salivation (86.8%), myosis (77.6%), sweating (50%), and bronchorrhea (35.5%). Atropine was used in 82.9% of patients (median = 2 days), intubation and mechanical ventilation in 46.1% (median = 3 days), and the median length of the hospital stay was 4 days. Plasma samples obtained upon admission in 59 cases revealed (LC-MS/MS): aldicarb (55), carbofuran (2), aldicarb and carbofuran (1), no active component (1). In most of the plasma and urine samples collected upon admission, the highest concentrations (ng/mL) obtained were for the active metabolite aldicarb sulphoxide (plasma, median = 831, IIQ = 99.2-2885; urine, median = 9800, IIQ = 2000-15000) than aldicarb (plasma, median = 237, IIQ = 35.7-851; urine, median = 584, IIQ = 166-1230), indicating rapid metabolism. The excretion of aldicarb and its metabolites was rapid since these compounds were rarely detected in plasma samples 48 hours after admission. Sequential cholinesterase analysis in 14 patients revealed almost complete reactivation in the first 48 hours post-admission, compatible for poisoning by carbamates. Based on the Poisoning Severity Score, the cases were classified as asymptomatic (5.3%), minor (11.8%), moderate (35.5%), severe (43.4%), and fatal (3.9%). CONCLUSIONS: Most poisonings involved aldicarb and resulted from suicide attempts; the poisonings were generally severe, with a mortality of 3.9%. Aldicarb was rapidly absorbed, metabolized, and excreted.

Surprising hair analysis results following acute carbofuran intoxication.

We present two non fatal cases of intoxication with carbofuran (CBF) documented by hair analysis. Carbofuran and 3-hydroxycarbofuran (OHCBF, its main metabolite) hair concentrations were determined using a liquid chromatography-tandem mass spectrometry method. The obtained results were surprising if we consider several hair analyses previously published and based on a theory of the presence of xenobiotic in the only segment that comprised its intake. Among the two intoxication cases, we noticed the presence of CBF and OHCBF in hair segments corresponding to 45 days before, and more than 100 days after, the day of intoxication. Additionally, repeated hair samplings and subsequent analysis revealed a decrease of the carbofuran's concentration during the hair life.

An unusual cause of death in poisoning: a case report.

Arterioesophageal fistula is a rare cause of upper gastrointestinal tract bleeding. Arterioesophageal fistula and haematemesis are rare in poisoning, especially in noncorrosive poisoning. An arterioesophageal fistula can occur in patients with retroesophageal subclavian artery. This is usually associated with prolonged presence of nasogastric tube.

Model study on the clinical signs and residue concentrations of sublethal carbofuran poisoning in birds.

The incidence of fatal poisoning of birds of prey caused by carbofuran has increased markedly in Hungary since 2007. An experimental model with broiler chickens was used to study clinical signs of sublethal carbofuran poisoning in birds and to measure the residue concentrations of carbamate in tissues after exposure. Eight chickens were treated with a carbofuran-containing insecticide orally by gastric tube at a single dose of 2.5 mg/kg body weight, and clinical signs of poisoning were observed. Gas chromatography was used to determine carbofuran concentrations in the blood, muscle, and liver samples, and in stomach contents. Poisoning was characterized by typical muscarinic and nicotinic clinical signs without mortality. Carbofuran in the stomach and edible tissues of acutely poisoned birds may lead to secondary poisoning of predators and may also present risks to human health.

Successful renal transplantation from a deceased donor with pesticide intoxication: a case report.

The number of individuals awaiting organ transplantation exceeds the number of organs. Patients who die from intoxication are rarely accepted as potential organ donors. Herein we have presented the results of kidney transplantations performed from a deceased 20-year-old female donor with suicidal ingestion of a pesticide (carbamate). The procured kidneys were successfully transplanted. Patients and grafts are doing well at 4 months following transplantation. There are few reports of successful transplantation of organs obtained from patients who die from various intoxications. Poisoned patients represent another pool of organ donors for transplantation services.

Carbofuran and its toxic metabolites provide forensic evidence for furadan exposure in vultures (Gyps africanus) in Kenya.

Forensic analysis of carbofuran residues in weathered tissue samples for evidence of Furadan exposure in vultures (Gps africanus) by HPLC gave concentration (mg/Kg dry tissue weight) ranges of bdl - 0.07 (carbofuran), bdl - 0.499 (3-ketocarbofuran) and 0.013-0.147 (3-hydroxycarbofuran) in beaks, bdl-0.65 (carbofuran), 0.024-0.190 (3-ketocarbofuran) and 0.017-0.098 (3-hydroxycarbofuran) in feet, 0.179-0.219 (3-ketocarbofuran) and 0.081-0.093 (3-hydroxycarbofuran) in crop content, 0.078-0.082 (3-ketocarbofuran) and 0.091-0.101 (3-hydroxycarbofuran) in muscle of a laced carcass and 0.006-0.014 (carbofuran), 0.590-1.010 (3-ketocarbofuran) and 0.095-0.135 (3-hydroxycarbofuran) in soil sampled from a poisoning site. These compounds were confirmed by GC-MS. The results showed that HPLC combined with GC-MS is suitable for forensic analysis of carbofuran residues in bird tissue samples and that forensic investigation should include its two toxic metabolites, 3-hydroxycarbofuran and 3-ketocarbofuran.

Investigation on possible ecotoxicological risk of carbofuran insecticides.

Carbofuran-containing insecticides are widely used agents in plant protection. Their use may pose considerable environmental risk for both the protected and non-protected predator and plantivorous birds. For defence of wild birds a model experiment was carried out on broiler chickens. In the study, eight animals were treated orally by gastric tube with a carbofuran-containing insecticide at a single dose of 2.5 mg/kg b.w. One animal served as untreated control specimen. Forage and drinking water were provided ad libitum. After the treatment, the possible clinical signs were observed carefully, blood samples were obtained from each bird and after exsanguinations liver, breast and leg muscle samples and stomach content were taken. The carbofuran concentration in blood, tissues and stomach content was determined by gas chromatographic method. Thirty minutes after poisoning, the average carbofuran concentration in breast muscle of chickens exceeded the maximum level of 0.1 mg/kg permitted in edible tissues, whereas ninety minutes after poisoning the concentration of one sample was still above the limit value. In the liver, leg-muscle and blood samples, the measured carbofuran concentration was lower than the permitted maximum value, except in the blood of two animals. The carbofuran concentration of the stomach content markedly exceeded the limit value. The sublethal concentration of the pesticides can reduce the capable of living of wild animals. Due to the sub toxic dose the poisoned birds can survive; however, the residue of insecticides can lead to secondary toxicosis of other animals.

Intentional poisoning cases of animals with anticholinesterase pesticide-carbofuran in Sri Lanka.

Carbofuran is a broad spectrum insecticide and nematicide which inhibits acetyl cholinesterase. Several intentional poisoning cases of animals and birds including crows, dogs, cow, and elephant, using carbofuran were reported in Sri Lanka. Qualitative analysis of carbofuran in biological specimens was carried out using T.L.C and GC-MS. The quantitative analysis was carried out by HPLC using Zorbax Eclips XDB-C18 (150 x 4.6 mm I.D x 5 microm particle size) column with acetonitrile: water 25:75 v/v mobile phase and UV detection at 210 nm. The liquid-liquid extraction with chloroform was reproducible and sensitive. The procedure was validated in terms of linearity (0.996