Pesticide contact dermatitis in agricultural workers of Himachal Pradesh (India)

Assessing the risk of induction of skin sensitization to plant protection products: A quantitative approach

Exposure to skin sensitizers is common and regulated in many industry sectors. For cosmetics, a risk-based approach has been implemented, focused on preventing the induction of sensitization. First, a No Expected Sensitization Induction Level (NESIL) is derived, then modified by Sensitization Assessment Factors (SAFs) to derive an Acceptable Exposure Level (AEL). The AEL is used in risk assessment, being compared with an estimated exposure dose, specific to the exposure scenario. Since in Europe there is increased concern regarding exposure towards potentially sensitizing pesticides via spray drift, we explore how existing practice can be modified to allow Quantitative Risk Assessment (QRA) of pesticides for bystanders and residents. NESIL derivation by the Local Lymph Node Assay (LLNA), the globally required in vivo assay for this endpoint, is reviewed alongside consideration of appropriate SAFs. Using a case study, the principle that the NESIL in μg/cm² can be derived by multiplying LLNA EC3% figure by a factor of 250 is adopted. The NESIL is then reduced by an overall SAF of 25 to establish an exposure level below which there is minimal bystander and resident risk. Whilst this paper focuses on European risk assessment and management, the approach is generic and universally applicable.

Parental exposure to propiconazole at environmentally relevant concentrations induces thyroid and metabolism disruption in zebrafish (Danio rerio) offspring: An in vivo, in silico and in vitro study

Propiconazole is used against fungal growth in agriculture and is released into the environment, but is a potential health threat to aquatic organisms. Propiconazole induces a generational effect on zebrafish, although the toxic mechanisms involved have not been described. The aim of this study was to investigate the potential mechanisms of abnormal offspring development after propiconazole exposure in zebrafish parents. Zebrafish were exposed to propiconazole at environmentally realistic concentrations (0.1, 5, and 250 μg/L) for 100 days and their offspring were grown in control solution for further study. Heart rate, hatching rate, and body length of hatched offspring were reduced. An increase in triiodothyronine (T₃) content and the T₃/T₄ (tetraiodothyronine) ratio was observed, indicating disruption of thyroid hormones. Increased protein level of transthyretin (TTR) in vivo was consistent with the in silico molecular docking results and T₄ competitive binding in vitro assay, suggests higher binding affinity between propiconazole and TTR, more than with T₄. Increased expression of genes related to the hypothalamus-pituitary-thyroid (HPT) axis and altered metabolite levels may have affected offspring development. These findings emphasizes that propiconazole, even on indirect exposure, represents health and environmental risk that should not be ignored.

Facial Irritant Contact Dermatitis Caused by Pyraclostrobin

Contact dermatitis and facial contact dermatitis caused by pesticides are not uncommon in China. However, clinically, due to the wide variety of pesticides, they mainly appear in the form of case reports. We reported a 70-year-old male patient developed facial irritant contact dermatitis (ICD) due to pyraclostrobin which was sprayed on his face. Initially, he felt facial burning and tingling, and localized erythematous-edematous and scaly rash appeared on his face as well as front hairline scalp. During the outpatient visit, the main symptoms were a facial burning sensation, itching, and tingling. The patient’s facial lesions improved after treatment. To better protect the skin of agricultural workers, preventive measures should be undertaken, such as personal protective equipment, gas masks, protective clothing and goggles, which are indispensable for manual pesticide spraying. Pyraclostrobin diluted according to the instructions is a potential source of ICD. Agricultural workers should undertake preventive measures during manual pesticide spraying. Safety education and publicity are particularly important. We need dermatologists to spread knowledge and agricultural workers to develop the right protective habits.

An outbreak of systemic intoxication with irritant contact dermatitis due cypermethrin in dairy cows - case report

ABSTRACT Pyrethroids are ectoparasiticides safe for mammals and widely used in farm animals. An outbreak of systemic intoxication with irritant contact dermatitis resulting from the use of cypermethrin pour on in dairy cows is reported in the state of Pernambuco. Eight adult animals were affected, three died on the property and five were referred to the Clínica de Bovinos, Universidade Federal Rural de Pernambuco, Campus Garanhuns. These received 100 mL of pour on Cypermethrin (Ectonil ®, Cipermetrina, Labgard, Brasil). Apathy, hyperexcitability, muscle tremors, sialorrhea, bradycardia and crusted lesions were observed on the dorsum of the neck, scapula, ears and ulcerations in the oral and vaginal mucosa. There was hyperfibrinogenemia and leukocytosis due to neutrophilia with a regenerative left shift. Histopathology showed areas of erosion and ulceration of the epidermis and perivascular lymphohistiocytic and neutrophilic infiltrate in the superficial dermis. Supportive treatment was done with improvement of systemic signs and skin lesions, however, in one animal (with 19 days hospitalized), there was no complete regression of neurological alterations of bradycardia and muscle tremors, even so, it was possible to return to productive activity. High doses of pour on cypermethrin may cause systemic intoxication in cattle and result in bradycardia, hyperexcitability, muscle tremors and sialorrhea with irritant contact dermatitis, and death in severe cases.

Differential immunomodulatory effects of six pesticides of different chemical classes on human monocyte-derived macrophage functions

Exposure to pesticides through eyes, skin, ingestion and inhalation may affects human health by interfering with immune cells, such as macrophages. We evaluated, in vitro, the effect of six pesticides widely used in apple arboriculture on the functions of human monocyte-derived macrophages (hMDMs). hMDMs were cultured for 4 or 24 h with or without pesticides (0.01, 0.1, 1, 10 μmol.L^-1). We showed that chlorpyrifos, thiacloprid, thiophanate, boscalid, and captan had little toxic effect at the tested concentrations, while dithianon had low-cytotoxicity at 10 μmol.L^-1. While boscalid showed no effect on hMDMs function, thiophanate (0.01 μmol.L^-1) stimulated with TPA and thiacloprid (1, 10 μmol.L^-1) stimulated with zymosan activated ROS production. Chlorpyrifos, dithianon, and captan inhibited ROS production and TNF-α, IL-1β pro-inflammatory cytokines. We established that dithianon (0.01-1 μmol.L^-1) and captan (0.1, 1 μmol.L^-1) induced mRNA expression of NQO1 and HMOX1 antioxidant enzymes. Dithianon also induced the mRNA expression of catalase, superoxide dismutase-2 at 10 μmol.L^-1. Together, these results show that exposure to chlorpyrifos, dithianon, and captan induce immunomodulatory effects that may influence the disease fighting properties of monocytes/macrophages while pesticides such as thiacloprid, thiophanate and boscalid have little influence.

Elements to increase translation in pyrethroid epidemiology research: A review

Pyrethroid insecticides have been the subject of numerous epidemiology studies in the past two decades. We examined the pyrethroids epidemiology literature published between 2016 and 2021. Our objective with this exercise was to inform interested readers regarding information on methodological elements that strengthen a study's use for translation (i.e., use in risk assessment) and to describe aspects of future research methods that could improve utility for decision-making. We focused on the following elements: (i) study design that provided evidence that pyrethroid exposure preceded the outcome, (ii) evidence that the method used for exposure characterization was reliable and sufficiently accurate for the intended purpose, and (iii) use of a robust approach for outcome ascertainment. For each of the 74 studies identified via the literature search, we categorized the methodological elements as Acceptable or Supplemental. A study with three Acceptable elements was considered Relevant for risk assessment purposes. Based on our evaluative approach, 18 (24%) of the 74 publications were considered to be Relevant. These publications were categorized as Acceptable for all three elements assessed: confirmed exposure (N = 24), confirmed outcome (N = 64), exposure preceded the outcome (N = 44). Three of these studies were birth cohorts. There were 15 Relevant publications of adults which included 10 Agricultural Health Study cohort publications of self-reported permethrin. Overall, the majority of the reviewed studies used methods that did not permit a determination that pyrethroid exposure preceded the outcome, and/or did not utilize robust methods for exposure assessment and outcome ascertainment. There is an opportunity for investigators and research sponsors to build on the studies reviewed here and to incorporate more translational approaches to studying exposure/outcome associations related to pesticides and other chemicals.

Effects of combined treatment of plasma activated liquid and ultrasound for degradation of chlorothalonil fungicide residues in tomato

The effects of combined treatment (PAL-U) of plasma-activated liquid (PAL) including plasma-activated water (PAW) and plasma-activated buffer solution (PABS) and ultrasound (U) for the degradation of chlorothalonil fungicide on tomato fruit was investigated. Distilled water and buffer solution were activated by radiofrequency plasma jet for durations of 1, 3, 5, and 10 min to obtain PAL₁ to PAL₁₀. Fruits were immersed in PAL for 15 min and also in distilled water with sonication for 15 min for individual treatments, and in PAL with sonication for 15 min for combined treatments. The maximum chlorothalonil fungicide residues were reduced by 89.28 and 80.23% for PAW₁₀-U and PABS₁₀-U, respectively. HPLC-MS characterization revealed chlorothalonil degradation pathway and formation of 2,4,5-trichloroisophthalonitrile, 2,4-dichloroisophthalonitrile, 4-chloroisophthalonitrile, isophthalonitrile and phenylacetonitrile as degradation products. Treatments also showed no negative effects on tomato quality. Therefore, PAL and PAL-U treatments could serve as effective methods for degrading pesticides on tomatoes.

Clinical, Occupational and Allergological Profile of 455 Patients with Occupational Contact Dermatitis: A 5-Year Study from a Tertiary Care Center of North India

Objectives:

To evaluate clinical and occupational profile and common allergens in patients with occupational contact dermatitis (OCD).

Materials and Methods:

The records of 455 (M:F 2:1) patients aged 18-85 years with allergic contact dermatitis were analyzed retrospectively. The diagnosis of OCD and patterns of dermatitis were defined by standard criteria. Indian standard series comprising 20 allergens and when suspected patient's own products were patch tested by Finn chamber method as per European Society of Contact Dermatitis guidelines and relevance of positive results was defined clinically.

Results:

Airborne contact dermatitis (27.7%), acral dermatitis (14.1%), hand dermatitis (12.9%), acrofacial dermatitis (12.7%), and facial dermatitis (10.5%) were the common patterns. Agriculturists (51.2%), homemakers (27.9%), office workers (24.6%), and construction workers (4.6%) comprised the majority. Positive patch test results in 58% cases were from parthenium (31.7%), p-paraphenylenediamine (PPD) (22.9%), nickel (16%), fragrance mix (11%), potassium dichromate (10.7%), cobalt (7.6%), and mercaptobenzothiazole (4.9%). Hair colorants, shoe chips, and shaving cream also produced relevant positive reactions. Parthenium, PPD, fragrance mix, and potassium dichromate in agriculturists; nickel, parthenium, PPD, fragrance mix, and potassium dichromate in women, and potassium dichromate and parthenium in construction workers elicited the most positive reactions. PPD and hair colorants elicited positive reaction mainly in office workers.

Conclusions:

The agriculturists, homemakers, and construction workers have OCD most frequently. Parthenium in farmers, potassium dichromate in construction workers, nickel in women, and PPD in office workers were the major contact allergens. The study is limited by its retrospective design, small number of patients, and limited number of patch test allergens.

Wild garlic extract reduces lipid peroxidation in terbuthylazine-treated human erythrocytes

Background: Among other negative effects, herbicides induce oxidative stress, leading to lipid peroxidation and protein oxidation. Therefore, there is a growing need to identify natural compounds with sufficient antioxidant capacity and mitigate the negative effects of herbicides without side effects.Objective: Our study aimed to examine the protective effect of the phenolic extract of wild garlic (WG) leaves on terbuthylazine-treated erythrocytes.Material and methods: In human erythrocytes treated with the herbicide terbuthylazine (4.5 mg/L) alone and a combination of terbuthylazine and WG extract, we measured malondialdehyde (MDA) and haemoglobin (Hb) concentrations and the antioxidant activities of CuZn superoxide dismutase (SOD1; EC 1.15.1.1) and catalase (CAT; EC 1.11.1.6) in vitro.Results: In comparison with terbuthylazine, WG extract reduced the concentrations of MDA and Hb from 59.69 to 43.45 nmol/gHb (27%, p < 0.001) and 165.08 to 128.64 g/L (22%, p < 0.05), respectively. Catalase activity was induced for samples treated with both WG extract and terbuthylazine compared with terbuthylazine alone (p < 0.05).Conclusions: The results demonstrated that WG may reduce the toxicity of terbuthylazine, and the erythrocyte membrane may be the primary site of phenolic action. Therefore, the lipid peroxidation intensity could be a biomarker of oxidative damage caused by terbuthylazine and the protective effect of WG.

Early embryonic exposure to chlorpyrifos-cypermethrin combination induces pattern deficits in the heart of domestic hen

Exposure to chlorpyrifos-cypermethrin combination during early development resulted in defective looping and ventricular noncompaction of heart in domestic chicken. The study was extended to elucidate the molecular basis of this novel observation. The primary culture of chicken embryonic heart cells showed a concentration-dependent loss of viability when challenged with this combination of technical-grade insecticides. Comet assay, DNA ladder assay, and analyses of appropriate markers at transcript and protein levels, revealed that chlorpyrifos-cypermethrin combination induced cell death by activating apoptosis. Parallelly, the tissues derived from control and experimental group hearts were checked for apoptotic markers, and the result was much similar to that of the in-vitro study. Further analysis showed that chlorpyrifos-cypermethrin combination deranged the expression pattern of the transcriptional regulators of cardiogenesis, namely TBX20, GATA5, HAND2, and MYOCD. This, together with heightened apoptosis, could well be the reason behind the observed structural anomalies in the heart of chlorpyrifos-cypermethrin poisoned embryos.

Patch Testing of Mercaptobenzothiazole and Mercapto Mix: The North American Contact Dermatitis Group Experience, 1994-2016

OBJECTIVES

Mercapto compounds are a category of rubber accelerators that may cause allergic contact dermatitis. This study characterizes patch test reactions to mercaptobenzothiazole (MBT) and mercapto mix (MM) in a large North American population.

METHODS

The 1994-2016 North American Contact Dermatitis Group screening series data were analyzed. Patients with allergic reactions to either MBT or MM (mercapto+) were included. The following characteristics were analyzed: strength of reaction, clinical and occupational relevance, coreactivity with other rubber accelerators, and sources of exposure.

RESULTS

A total of 49,795 patients were tested to mercapto compounds from 1994 to 2016; 633 (1.3%) had positive reactions to MBT and/or MM. The frequency to both MBT and MM significantly decreased over time (P < 0.0001). Mercapto+ patients were significantly more likely to be male, have occupationally related skin disease, and report involvement of the hands and/or feet (P < 0.0001). They were significantly less likely to have face, scalp/ears/neck, or trunk involvement (P ≤ 0.0001). There was significant coreactivity with carba mix (23.4%) and thiuram mix (32.5%). Mercaptobenzothiazole and MM reactions were frequently clinically (81.7% and 83.5%, respectively) and occupationally relevant (29.8% and 33.4%, respectively). Gloves were the most common source (31.3% and 30.9%, respectively).

CONCLUSIONS

Patch test positivity to mercapto compounds significantly decreased from 1994 to 2016 but remains clinically and occupationally relevant.

Occupational airborne contact urticaria, anaphylaxis and asthma in farmers and agronomists due to Bruchus pisorum

BACKGROUND

Occupational contact urticaria due to inhalation of legume pest allergens has rarely been described.

OBJECTIVE

To determine the cause of an outbreak of airborne contact urticaria, asthma, and anaphylaxis in farmers and agronomists studying the disinsectization of dried peas. Peas were treated with aluminum phosphide (EPA).

METHODS

Extracts prepared from Bruchus lentis and Bruchus pisorum bodies and from healthy legumes, EPA-treated legumes, and infested legumes, were used for in vivo tests (skin prick testing, oral, and specific bronchial challenge for the diagnosis of asthma and anaphylaxis) in affected patients and in five control patients with severe legume hypersensitivity. Open application, patch testing with the most common legume insecticides, molecular analysis, and IgE immunoblotting were undertaken.

RESULTS

We found positive responses (prick, provocation, immune detection) to parasitic pea extracts and B. pisorum. A 25 kDa band was detected in the western blot of all patients who worked with infested EPA-treated peas. Bands from B. pisorum extract were detected in all patients. No responses to pea allergens were found in any patient, unlike in legume allergy controls. Oral provocation tests were negative.

CONCLUSION

B. pisorum is a cause of contact urticaria and may cause occupational hives, anaphylaxis, and asthma. The allergen may enter by inhalation or puncture of setae released by B. pisorum.

Contact Allergy-Emerging Allergens and Public Health Impact

Contact allergy (sensitisation) and allergic contact dermatitis (ACD) resulting from it have a considerable public health impact. For the present review, all pertinent articles were systematically searched via Medline and Web of Science™; additionally, all available issues of the journals "Contact Dermatitis" and "Dermatitis" were manually searched, covering the years 2018-2019, thereby extending and re-focusing a previous similar review. New allergens, or previously described allergens found in a new exposure context or of other current importance, are described in sections according to substance classes, e.g., metals, preservatives, fragrances. As a common finding in many investigations, a lack of information on product composition has been noted, for instance, regarding a newly described allergen in canvas shoes (dimethylthiocarbamylbenzothiazole sulfide) and, most notably, absence of co-operation from manufacturers of glucose-monitoring devices and insulin pumps, respectively. These latter devices have been shown to cause severe ACD in a considerable number of diabetic patients caused by the liberation of isobornyl acrylate and N,N'-dimethylacrylamide, respectively, as demonstrated by an international collaboration between dermatologists and chemists. Improved and complete ingredient labelling for all types of products, and not just cosmetics, must be put on the legislative agenda.