Acute Metam Sodium Poisoning Caused by Occupational Exposure at a Flower Farm - Uganda, October 2016.

On October 25, 2016, media reports alerted the Uganda Ministry of Health to an outbreak of >80 cases of vomiting, syncope, and acute diarrhea among workers at a flower farm in central Uganda; 27 workers were hospitalized. On November 1, an investigation was undertaken by the Uganda Public Health Fellowship Program.* A case-control study found that working inside greenhouse 7, which had been fumigated with the organosulfur compound metam sodium the night of October 13, was strongly associated with illness. Employees who worked in this greenhouse during October 14-21 reported a strong "suffocating" smell in the greenhouse. Investigation revealed that, in violation of safety protocols, workers did not properly cover the soil after fumigation, allowing vapors to become trapped inside the greenhouse. The farm management, unaware of the lapse, failed to inform workers to avoid the vicinity of the fumigation. Respiratory protective measures were not routinely available for workers, which likely contributed to the severity and extent of the outbreak. Although metam sodium is generally considered to be of low risk when used according to manufacturer's instructions (1), occupational exposure in the absence of recommended safety measures can have serious health consequences. The investigation highlighted the importance of identifying potential occupational hazards to workers, as well as establishing safety protocols in occupational settings, training workers at risk, such as pesticide sprayers and flower pickers,† and ensuring enforcement of safety protocols. After this outbreak, the farm management reviewed, revised, and trained the workers on safety protocols to prevent future outbreaks.

Cartap Hydrochloride Poisoning.

Cartap hydrochloride is a moderately hazardous nereistoxin insecticide that is increasingly used for deliberate self-harm in India. It can cause neuromuscular weakness resulting in respiratory failure. We report a patient with 4% Cartap hydrochloride poisoning who required mechanical ventilation for 36-hours. He recovered without any neurological deficits. We also review literature on Cartap hydrochloride poisoning.

Metam sodium intoxication: the specific role of degradation products--methyl isothiocyanate and carbon disulphide--as a function of exposure.

Introduction. The objective was to evaluate the toxicity of poisoning by metam sodium, a dithiocarbamate fumigant, the breakdown products of which are methyl isothiocyanate (MITC), carbon disulphide (CS2), and dihydrogen sulphide (H2S). Methods. This is a retrospective, observational case series of metam sodium exposure cases reported to the Angers Poison and Toxicovigilance Centre from 1992 through 2009. Results. A total of 106 cases of metam sodium exposure were recorded and 102 cases were included in this study. All cases of exposure were unintentional. Occupational poisoning occurred in eight cases. The most common route of exposure was inhalation (n = 96). In 79 cases, the patients were people living near fields where metam sodium had recently been applied. Most of the reported symptoms involved irritation of the eyes (n = 76), throat and nose (n = 65), attributable to MITC. Cough and dyspnoea occurred in four cases but no persistent, irritant-induced asthma or persistent exacerbation of asthma was observed. Sixteen patients at two different sites of pollution were exposed to emanations from the drainage system in their homes following the illicit discharge of metam sodium into the sewers. Most presented with nausea and headaches, but only four experienced eye or throat irritation. A breakdown product other than MITC was involved: air analysis at one site revealed the presence of CS2 (337 mg/m(3)) and no H2S. Two of these patients, who had consumed some alcohol, experienced dysgeusia but no disulfiram-like reaction. The only lethal case recorded was a truck driver who was found dead of acute lung injury after falling into a tank that had previously contained metam sodium. Two patients who ingested a dilute solution, presented with mild epigastric pain. Four skin exposures caused erythema (n = 2), moderate burns (n = 1), and urticaria (n = 1). According to the poisoning severity score, their symptoms were minor in 99% of cases. Conclusion. Acute metam sodium exposure usually causes minor symptoms. They vary as a function of the circumstances of exposure, which determine the degradation product that forms. On contact with moist soil, metam sodium decomposes into MITC and causes irritant symptoms. Under specific conditions, such as a spillage in the drainage system, metam sodium can degrade into CS2 and cause neurological signs.

Fatal human poisoning with Padan: a cartap-containing pesticide.

We report a patient who ingested about 13 g of Padan SG, a cartap-containing pesticide. After ingestion, the patient developed multiple seizures and dyspnea and lost consciousness. The patient did not recover and died on the fifth hospital day despite treatment at the early stage of poisoning. The cause of death was multisystem organ failure. Results of toxicological analysis were as follows: concentrations of nereistoxin (cartap metabolite) were 10.6 microg/mL in plasma, 18.2 microg/mL in urine, and 2.6 mg/mL in gastric fluid. Results of drug screening of urine by Triage DOA Panels and using an organophosphate detection kit were negative.

Cancer incidence among pesticide applicators exposed to butylate in the Agricultural Health Study (AHS).

Although limited, epidemiologic studies suggest possible associations between butylate use and cancer risk, specifically prostate cancer and non-Hodgkin lymphoma (NHL). We examined butylate use and cancer risk more broadly in the AHS, a cohort of licensed pesticide applicators in Iowa and North Carolina. Pesticide use information was collected using self-administered questionnaires. Poisson regression was used to calculate rate ratios (RR) and 95% confidence intervals (CI). Two exposure metrics were used: lifetime exposure days (LD) and intensity-weighted lifetime exposure days (IWLD). We used two referent groups: unexposed to butylate and the lowest butylate usage category. This analysis included 19,655 applicators with complete butylate use information; 5297 applicators were exposed to butylate, making this the largest study of butylate to date. The mean follow-up time since enrollment was 9 years. Prostate cancer risk was significantly elevated among applicators in the highest LD category in both referent groups (low-exposed referent: RR(LD)=2.09, 95% CI=1.27-3.44). We observed a significantly elevated joint effect of prostate cancer family history and high butylate usage across both exposure metrics and both referent groups (low-exposed referent: RR(LD)=2.00, 95% CI=1.07-3.74), and a non-significant, elevated interaction between butylate use and prostate cancer family history, similar to a previous AHS finding. Statistically significant increased risks and exposure-response trends were seen for all lymphohematopoietic cancers (AL) and NHL for both exposure metrics and referent groups (low-exposed referent: AL:RR(LD)=2.27, 95% CI=1.18-4.37; NHL: RR(LD)=3.44, 95% CI=1.29-9.21). Our analysis did not find meaningful associations for other cancers analyzed. Further study is warranted for AL, NHL and prostate cancers.

Thiodicarb and methomyl tissue distribution in a fatal multiple compounds poisoning.

Thiodicarb is a nonsystemic carbamate insecticide whose acetylcholinesterase activity is related to its main methomyl degradation product. A 40-year-old woman was found dead in her car. Empty packages of medicines and an open bottle of Larvin containing thiodicarb were found near her body. No signs of violence nor traumatic injuries were noticed upon autopsy, and police investigations strongly suggested a suicide. Systematic toxicological analysis performed on postmortem specimens revealed the presence of various sedatives, hypnotics, and antipsychotic drugs in blood, urine, and gastric content. Some of the compounds identified were determined at blood concentrations well above the known therapeutic concentrations: zolpidem (2.87 mg/L), bromazepam (2.39 mg/L), nordazepam (4.21 mg/L), and levopremazine (0.64 mg/L). Specific analysis of thiodicarb and of its methomyl metabolite was then performed on all fluids and tissues collected during autopsy by liquid chromatography ion trap tandem mass spectrometry (LC-MS-MS). The anticholinesterase capacity of blood, urine, and gastric content collected at autopsy was 83%, 82%, and 32%, respectively (normal value: 0%). The presence of thiodicarb in the bottle found near the body corroborates the hypothesis of an intake of that compound. Although thiodicarb was only detected in gastric content (24.3 mg/L), its methomyl metabolite was quantified in most postmortem tissues and fluids: gastric content (19.9 mg/L), peripheral blood (0.7 mg/L), urine (8.5 mg/L), bile (2.7 mg/L), liver (0.7 mg/kg), kidney (1.7 mg/kg), lung (1.5 mg/kg), brain (9.3 mg/kg), and heart (3.6 mg/kg).

Inhibition of nuclear factor-kappa B nuclear localization reduces human E-selectin expression and the systemic inflammatory response.

BACKGROUND: One proinflammatory property observed during endothelial cell activation is the expression of the neutrophil adhesion molecule E-selectin on the surface of endothelial cells. An important regulatory element in endothelial cell E-selectin expression is the nuclear localization of the transcription factor nuclear factor (NK)-kappa B, which binds to and affects the function of several genes encoding proteins mediating inflammation. METHODS AND RESULTS: In this study, we investigated the ability of pyrrolidine dithiocarbamate (PDTC), an agent that inhibits the nuclear localization of NF-kappa B, to (1) block endothelial cell E-selectin expression in vitro in response to tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, and lipopolysaccharide (LPS) and (2) reduce neutrophil infiltration in a rabbit model of systemic inflammation. As measured with the use of an enzyme-linked immunosorbent assay, TNF-alpha, IL-1, and LPS each induced a significant increase in surface expression of E-selectin in cultured human umbilical vein endothelial cells (HUVECs) compared with HUVECs treated with medium alone. In contrast, E-selectin surface expression was blocked in HUVECs pretreated with PDTC before TNF-alpha, IL-1, or LPS stimulation. NF-kappa B was present in HUVEC nuclei treated with TNF-alpha, whereas translocation of NF-kappa B to the nucleus was absent in TNF-alpha-treated HUVECs pretreated with PDTC. In vivo, rabbits pretreated with PDTC before LPS infusion showed significantly less neutrophil infiltration in the lungs, liver, and heart compared with animals infused with LPS alone. This correlated with a reduction in E-selectin expression in vivo. CONCLUSIONS: Our data suggest that NF-kappa B regulation of gene expression in the vascular endothelium may be an important cellular mechanism in endothelial cell activation.

Effects of environmental synthetic chemicals on thyroid function.

Synthetic chemicals are released into the environment by design (pesticides) or as a result of industrial activity. It is well known that natural environmental chemicals can cause goiter or thyroid imbalance. However, the effects of synthetic chemicals on thyroid function have received little attention, and there is much controversy over their potential clinical impact, because few studies have been conducted in humans. This article reviews the literature on possible thyroid disruption in wildlife, humans, and experimental animals and focuses on the most studied chemicals: the pesticides DDT, amitrole, and the thiocarbamate family, including ethylenethiourea, and the industrial chemicals polyhalogenated hydrocarbons, phenol derivatives, and phthalates. Wildlife observations in polluted areas clearly demonstrate a significant incidence of goiter and/or thyroid imbalance in several species. Experimental evidence in rodents, fish, and primates confirms the potentiality for thyroid disruption of several chemicals and illustrates the mechanisms involved. In adult humans, however, exposure to background levels of chemicals does not seem to have a significant negative effect on thyroid function, while exposure at higher levels, occupational or accidental, may produce mild thyroid changes. The impact of transgenerational, background exposure in utero on fetal neurodevelopment and later childhood cognitive function is now under scrutiny. There are several studies linking a lack of optimal neurological function in infants and children with high background levels of exposure to polychlorinated biphenyls (PCBs), dioxins, and/or co-contaminants, but it is unclear if the effects are caused by thyroid disruption in utero or direct neurotoxicity.

The emergency medical response to the Cantara hazardous materials incident.

On 14 July 1991, at 2150 h, a train derailment occurred near the Cantara rail curve about six miles above Dunsmuir in Northern California. The derailment spilled approximately 19,000 gallons of metam-sodium into the Sacramento River. When mixed with water, metam-sodium degrades to methylisothiocyanate (MITC) and other gases. The contaminated river water passed the town of Dunsmuir and other occupied areas exposing residents to MITC gas. From 15 July to 20 July (five days), a total of 360 people underwent triage. The majority of patients displayed minor exposure symptoms that did not require hospital care. Mercy Mt. Shasta Hospital, a small rural hospital close to Dunsmuir, received the majority of patients. As of 29 July, 15 days after the incident, Mercy Mt. Shasta Hospital had seen 244 exposed patients in its emergency department, and had admitted five. Three had symptoms that could have been spill-related. Three Regional Poison Control Centers provided medical toxicology advice. Medical management of the emergency medical services (EMS) response to the event was piecemeal and weak. There did not appear to be a medical operations component at local Emergency Operations Centers (EOC). Most health care personnel interviewed complained about inadequate information about the substance and the situation. Local fire service mutual-aid agreements to obtain additional fire service and ambulance personnel worked well. It is important to emphasize that everyone who believed they had been exposed to the chemical underwent triage and received appropriate acute medical care.

[Antidotal effects of sulfhydryl compounds on acute poisonings by sodium ammonium dimethyl-2-(propane-1,3-dithiosulfate) monohydrate, nereistoxin and cartap].

Sodium dimercaptopropanesulphonate (DMPS) and sodium dimercaptosuccinate (DMS) were discovered to be effective antidotes for acute poisoning of insecticides SCD [sodium ammonium dimethyl-2-(propane-1,3-dithiosulfate) monohydrate], nereistoxin (4-N,N-dimethylamino-1,2-dithiolane) and cartap (dihydronereistoxin dicarbamate). In mice, DMPS (250 mg/kg) or DMS (1000 mg/kg) ip 20 min before SCD increased LD50 of ig SCD from 97 to 374 or 251 mg/kg, respectively. The prophylactic effect of DMPS was better than that of DMS. Administration of DMPS prior to cartap increased LD50 of ig cartap from 130 to 375 mg/kg. The therapeutic effect of DMPS was also demonstrated in SCD-poisoned conscious rabbits. DMPS 62.5 mg/kg or DMS 500 mg/kg iv completely antagonized the neuromuscular blockade and respiratory depression caused by SCD, nereistoxin and cartap in anesthetized rabbits. The antagonism of SCD-induced neuromuscular blockade by cysteine (400 mg/kg, iv) was less effective and of shorter duration than that by DMPS and DMS. Dimercaprol 50 mg/kg im showed little effect on SCD-induced paralysis. The antagonistic actions of sulfhydryl compounds on neuromuscular blockade induced by these insecticides probably belong to chemical antagonism.

Acute intoxication due to exposure to maneb and zineb. A case with behavioral and central nervous system changes.

The dithiocarbamates are considered chemicals of low toxicity. They are known to cause dermatitis, conjunctivitis, rhinitis, pharyngitis, and bronchitis in humans. Central nervous system effects in humans have not been found, but some cases have been reported in experimental animals. This case report concerns a 42-year-old man previously in good health, who sprayed a combined dithiocarbamate of maneb and zineb on a cucumber plantation twice during a week, the second time with a more concentrated solution than the first. Behavioral changes appeared after he walked through the sprayed area following the first application, and loss of consciousness, convulsions, and right hemiparesis with diffuse slow rhythm in the electroencephalogram occurred after the second exposure. Both the behavioral and central nervous system symptomatology disappeared spontaneously after a few days. An electroencephalogram was normal two weeks later. The absence of a positive previous history of the patient, the sudden appearance and spontaneous disappearance of the symptoms, and the apparent dose-response relationship strongly suggested that maneb and zineb were the cause of the illness.

Acute central nervous system changes due to intoxication by Manzidan (a combined dithiocarbamate of Maneb and Zineb).

A 42-year old man sprayed Manzidan (a combined dithiocarbamate of Maneb and Zineb) on a cucumber plantation, twice during a week. Behavioural changes appeared after the first application, and loss of consciousness, convulsions and right hemiparesis after the second application with diffuse slow rhythm in the EEG. Both the behavioural and CNS symptomatology disappeared spontaneously after a few days. The previous history of the patient, the sudden appearance and spontaneous disappearance of the symptoms and a dose-response relationship strongly suggest that Maneb and Zineb were the cause of the illness.