Comparative study of subchronic toxicities of mosquito repellents (coils, mats and liquids) on vital organs in Swiss albino mice

Systematic review of clinical manifestations, management and outcome following accidental ingestion of liquid mosquito repellent vaporiser in children

BACKGROUND

Pyrethroid-based mosquito repellents are widely used to control mosquito-borne diseases. Liquid mosquito-repellent vaporisers are effective modes of pyrethroid delivery but can also pose significant health risks if ingested or used improperly.

OBJECTIVE

This systematic review was performed to assess the demographic distribution, clinical presentation, management strategies and outcomes in children resulting from accidental ingestion of liquid mosquito repellent vaporiser.

METHODS

The study adheres to the reporting standards outlined in the PRISMA Statement for Systematic Reviews and was prospectively registered with PROSPERO (record # CRD42023413937) to enhance transparency and minimise reporting bias. A comprehensive search was conducted on PubMed, Scopus and Google Scholar using specific MeSH terms related to insecticides, mosquito repellents, pyrethroids, ingestion, poisoning, toxicity and prevention. The reference lists of the included studies were also reviewed for additional relevant articles. The inclusion criteria involved studies published in peer-reviewed journals between 2000 and 2023 that focused on children under 18 years old with a history of mosquito-repellent ingestion based on primary data.

RESULTS

Twelve studies met the inclusion criteria; these were primarily case reports from India, China and the UAE. Male children were predominantly affected, and symptoms included vomiting, convulsions, cough and respiratory distress. Management primarily involved supportive and symptomatic measures, including atropine for salivation and antiepileptic drugs for seizures. Respiratory support was provided for respiratory complications.

CONCLUSION

Despite the known risks and diverse presentations of pyrethroid poisoning caused by liquid mosquito repellent vaporiser in children, the limited substantial evidence in the literature underscores the urgent need for comprehensive research to refine management approaches and enhance preventive measures.

Rhodomyrtus tomentosa (Aiton) Hassk. (haramonting) protects against allethrin-exposed pulmo damage in rats: mechanistic interleukins

Inhaling Allethrin (C19H26O3) may induce oxidative stress in lung cells by causing the formation of free radi-cals. Interleukins (IL) are a group of secreted cytokines or proteins and signaling molecules initially produced as an immune response by leukocytes. Rhodomyrtus tomentosa (Aiton) Hassk. (haramonting) contains antioxidants that may prevent lung damage induced by allethrin-containing electric mosquito repellents. In this study, six groups of rats were exposed to allethrin via an electric mosquito repellent, including positive, negative, and comparison control groups and three groups were administered Rhodomyrtus tomentosa (Aiton) Hassk at 100 mg/kg BW, 200 mg/kg BW, and 300 mg/kg BW. After 30 days, the pulmonary tissue and the blood were taken for immunohisto-chemical and ELISA analysis. The accumulation of inflammatory cells causes the thickening of the alveolar wall structures. Injuries were more prevalent in the A+ group than in the other groups. The connection between the alveoli and blood capillaries, which can interfere with alveolar gas exchange, is not regulated, and the lu-minal morphology is aberrant, causing damage to the alveolar epithelial cells. Exposure to electric mosquito coils containing allethrin can increase the expression of interleukin-1, interleukin-8, interleukin-9, and interleu-kin-18 in blood serum and tissues while decreasing the expression of interleukin-6 and interleukin-10. Like the Vitamin C group, Rhodomyrtus tomentosa can increase alveolar histological alterations by decreasing the ex-pression of IL-1β, IL-8, IL-9, and IL-18 while increasing IL-6 and IL-10. So that this plant can be developed in the future as a drug to prevent lung harm from exposure.

Toxicological and histopathological alterations in the heart of young and adult albino rats exposed to mosquito coil smoke

Mosquito coil repellents are well-known indoor air pollutant with significant health concerns. The present study investigated the toxic effects of mosquito coil smoke on the heart of young and adult male rats. The animals were subjected to the smoke for 6 h/day, 6 days/week, for 4 weeks. Within the first hour after lighting the coil, significant amounts of formaldehyde, total volatile organic compounds, and particulate matter (PM2.5 and PM10) were detected. Both exposed ages, particularly the young group, showed a significant increase in the activities of serum aspartate aminotransferase, lactate dehydrogenase, creatine kinase-MB, and the levels of troponin I, myoglobin, Na+ levels, lipid profile, and inflammatory markers (interleukin-6 and C-reactive protein) as well as a significant decrease in K+ levels and cardiac Na-K ATPase activity, indicating development of cardiac inflammation and dysfunction. Furthermore, the toxic stress response was validated by significant downregulation at expression of the detoxifying enzyme cytochrome p450. Histopathological studies in both age groups, especially the young group, revealed cardiomyocyte degeneration and necrotic areas. Moreover, upregulation at the pro-apoptotic markers, caspase3, P53, and cytochrome C expressions, was detected by immunohistochemical approach in heart sections of the exposed groups. Finally, the myocardial dysfunctional effects of the coil active ingredient, meperfluthrin, were confirmed by the docking results which indicated a high binding affinity of meperfluthrin, with Na-K ATPase and caspase 3. In conclusion, both the young and adult exposed groups experienced significant cardiac toxicity changes evidenced by cell apoptosis and histopathological alterations as well as disruption of biochemical indicators.

Can Potted Plants Catch Mosquitoes? Applying Rare-Earth Luminescent Materials and Plant Energy to the Development of Innovative Mosquito-Trapping Potted Plants

Due to the global warming crisis, the spread of various infectious diseases is worsening, with mosquito-borne contagious diseases posing a significant threat. While many residential and public spaces contain plants, often for greening the environment and improving mental and physical well-being, the carbon dioxide released by these plants produces ideal habitats for mosquitoes. Considering the quality of life of urban residents and the development of health-related products simultaneously is an important topic. This study used diverse complementary techniques, such as energy-storing rare-earth luminescent materials, sustainable power generation using plant energy, blue light-emitting diodes, and environmentally friendly fermentation formula, to develop planting products with potential mosquito control functionality. The prototype design for this mosquito-trapping potted plant has been patented. The aim of this paper is to discuss the design principles adopted to improve the defects of existing mosquito-trapping designs, the green energy materials and techniques employed, the architecture configuration of the product prototype, and the test results. By integrating green materials and technology, the prototype can be self-powered without being plugged in to yield conspicuous energy savings. The results showed that the developed multi-function products, combined with the concept of energy sustainability, can improve global public health as well as individuals' physical and mental health.

Allethrin Promotes Apoptosis and Autophagy Associated with the Oxidative Stress-Related PI3K/AKT/mTOR Signaling Pathway in Developing Rat Ovaries

The increased concern regarding the reduction in female fertility and the impressive numbers of women undergoing fertility treatment support the existence of environmental factors beyond inappropriate programming of developing ovaries. Among these factors are pyrethroids, which are currently some of the most commonly used pesticides worldwide. The present study was performed to investigate the developmental effects of the pyrethroid-based insecticide allethrin on ovarian function in rat offspring in adulthood. We mainly focused on the roles of oxidative stress, apoptosis, autophagy and the related pathways in ovarian injury. Thirty-day-old Wistar albino female rats were intragastrically administered 0 (control), 34.2 or 68.5 mg/kg body weight allethrin after breeding from Day 6 of pregnancy until delivery. We found that allethrin-induced ovarian histopathological damage was accompanied by elevations in oxidative stress and apoptosis. Interestingly, the number of autophagosomes in allethrin-treated ovaries was higher, and this increase was correlated with the upregulated expression of genes and proteins related to the autophagic marker LC-3. Furthermore, allethrin downregulated the expression of PI3K, AKT and mTOR in allethrin-treated ovaries compared with control ovaries. Taken together, the findings of this study suggest that exposure to the pyrethroid-based insecticide allethrin adversely affects both the follicle structure and function in rat offspring during adulthood. Specifically, allethrin can induce excessive oxidative stress and defective autophagy-related apoptosis, probably through inactivation of the PI3K/AKT/mTOR signaling pathway, and these effects may contribute to ovarian dysfunction and impaired fertility in female offspring.

Myrica salicifolia Hochst. ex A. Rich. suppress acetic acid-induced ulcerative colitis in rats by reducing TNF-alpha and interleukin-6, oxidative stress parameters and improving mucosal protection

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) with rising prevalence in developing countries, and limited success of current therapies, natural products have immense potential for therapy due to their "disease modifying and side-effect neutralizing" potential. Myrica salicifolia is traditionally used for gastrointestinal diseases and have reported antiinflammatory activities, but its use in IBD has not yet been studied. Therefore, in the present study, the effects of the root extract of M. salicifolia (Ms.Cr) were investigated using the acetic acid-induced UC model in rats. For 6 days, the rats were given either vehicle (10 mL/kg), lower (200 mg/kg), and higher (400 mg/kg) doses of Ms.Cr, or the positive control drug (prednisolone; 2 mg/kg) orally. A single dosage of 5% acetic acid (1.0 mL) was administered intrarectally to rats on day 6 to induce UC. Disease activity index (DAI), histological observations, the biochemical parameters related to oxidative stress, and specific cytokines such as interleukin-6 (IL-6) and the tumor necrosis factor-α (TNF-α) were determined to assess the effect of Ms.Cr. In comparison to the AA-induced colitis rats, Ms.Cr's pretreatment significantly decreased DAI, colonic ulceration, and inflammatory score. Total glutathione levels and catalase activity were considerably recovered in the colitis group treated with Ms.Cr, whereas enhanced lipid peroxidation in colon tissues was significantly decreased. Moreover, Ms.Cr pretreatment also caused inhibition of the activation of IL-6 and TNF-α in the colonic tissues of respective groups. Based on these findings, Ms.Cr might be developed to treat UC in the future.

Toxicological Evaluation of Novel Cyclohexenone Derivative in an Animal Model through Histopathological and Biochemical Techniques

Toxicity studies were conducted to provide safety data of potential drug candidates by determining lethal and toxic doses. This study was designed for pre-clinical evaluation of novel cyclohexenone derivative with respect to the acute and sub-acute toxicity along with the diabetogenic potential. Acute and sub-acute toxicity were assessed after intraperitoneal (i.p) injection of the investigational compound through selected doses for 21 days. This was followed by assessment of isolated body organs (liver, kidney, heart and pancreas) via biochemical indicators and histopathological techniques. No signs of toxicity were revealed in the study of acute toxicity. Similarly, a sub-acute toxicity study showed no significant difference in biochemical indicators on 11th and 21st days between treated and control groups. However, in blood urea nitrogen (BUN) and random blood glucose/sugar (RBS) values, significant differences were recorded. Histopathological evaluation of liver, kidney, pancreas and heart tissues revealed mild to severe changes in the form of steatosis, inflammation, fibrosis, necrosis and myofibrillary damages on 11th and 21st days of treatment. In conclusion, the median lethal dose of the tested compound was expected to be greater than 500 mg/kg. No significant change occurred in selected biomarkers, except BUN and RBS levels, but a histopathological study showed moderate toxic effect on liver, kidney, pancreas and heart tissues by the cyclohexenone derivative.

Exposure to Particulate PAHs on Potential Genotoxicity and Cancer Risk among School Children Living Near the Petrochemical Industry

This study aimed to assess the association of exposure to particle-bound (PM_2.5) polycyclic aromatic hydrocarbons (PAHs) with potential genotoxicity and cancer risk among children living near the petrochemical industry and comparative populations in Malaysia. PM_2.5 samples were collected using a low-volume sampler for 24 h at three primary schools located within 5 km of the industrial area and three comparative schools more than 20 km away from any industrial activity. A gas chromatography-mass spectrometer was used to determine the analysis of 16 United States Environmental Protection Agency (USEPA) priority PAHs. A total of 205 children were randomly selected to assess the DNA damage in buccal cells, employing the comet assay. Total PAHs measured in exposed and comparative schools varied, respectively, from 61.60 to 64.64 ng m^-3 and from 5.93 to 35.06 ng m^-3. The PAH emission in exposed schools was contributed mainly by traffic and industrial emissions, dependent on the source apportionment. The 95th percentiles of the incremental lifetime cancer risk estimated using Monte Carlo simulation revealed that the inhalation risk for the exposed children and comparative populations was 2.22 × 10^-6 and 2.95 × 10^-7, respectively. The degree of DNA injury was substantially more severe among the exposed children relative to the comparative community. This study reveals that higher exposure to PAHs increases the risk of genotoxic effects and cancer among children.

Protective Effect of Thymus serrulatus Essential Oil on Cadmium-Induced Nephrotoxicity in Rats, through Suppression of Oxidative Stress and Downregulation of NF-κB, iNOS, and Smad2 mRNA Expression

The purpose of the research was to examine the protective effect of essential oil from Thymus serrulatus Hochst. ex Benth. (TSA oil) against cadmium (Cd)-induced renal toxicity. The experimental protocol was designed using 30 healthy adult Wistar albino rats allocated into five groups containing six animals in each group. Group 1 was treated as normal control and groups 2, 3, 4, and 5 were treated with cadmium chloride (CdCl₂, 3 mg/kg, IP) for 7 days. Group 3 was also treated with silymarin (100 mg/kg, PO) as a standard group, while groups 4 and 5 were administered with TSA oil at doses of 100 and 200 mg/kg PO, respectively. The nephrotoxicity was measured with various parameters such as kidney function markers, oxidative stress markers (glutathione (GSH) and malondialdehyde (MDA)), and messenger ribonucleic acid (mRNA) expression levels of inflammatory factors. The histological studies were also evaluated in the experimental protocol. The CdCl₂-treated groups showed a significant increase in the levels of serum kidney function markers along with MDA levels in kidney homogenate. However, renal GSH level was found to be reduced significantly. It was found that CdCl₂ significantly upregulated the nuclear factor levels of kappaB (NF-κB p65), inducible nitric oxide synthase (iNOS), and small mothers against decapentaplegic (Smad2) as compared to the normal control group. On the other hand, TSA oil significantly improved the increased levels of serum kidney function markers, non-enzymatic antioxidants, and lipid peroxidation. In addition, TSA oil significantly downregulated the increased expression of NF-κB p65, iNOS, and Smad2 in Cd-intoxicated rats. Moreover, the histological changes in the tissue samples of the kidney of Cd-treated groups were significantly ameliorated in the silymarin- and TSA-oil-treated groups. The present study reveals that TSA oil ameliorates Cd-induced renal injury, and it is also proposed that the observed nephroprotective effect could be due to the antioxidant potential of TSA oil and healing due to its anti-inflammatory action.

Blends of neem oil based polyesteramide as nanofiber mats to control Culicidae

Mosquitoes act as vectors for several disease-causing microorganisms and pose a threat to mankind by transmitting various diseases. There are different conventional methods to repel or kill these mosquitoes for avoiding susceptibility against infections. However, to overcome the difficulties with conventional methods, new advanced materials are being studied. For the first time, we report developing a nanofiber mat with a controlled release of insecticide to repel or detain the mosquitoes. Briefly, various blend compositions were prepared by manipulating the ratio of neem oil-based polyesteramide (PEA) and polycaprolactone (PCL) immobilized with insecticide, transfluthrin (Tf). The blend solutions were electrospun to get non-woven nanofiber mats, and these nanomaterials were characterized by various spectroscopic techniques to understand their physicochemical properties. The surface morphology was analyzed using environmental scanning electron microscopy (E-SEM), and the diameter of the nanofibers was in the range of 200 to 450 nm. Further, thermal and mechanical properties were evaluated to understand the stability of nanofiber mats. In vitro drug release studies of nanofiber mat PPT-1335 showed controlled and sustained release of Tf, with ∼35% of Tf released in 24 h. However, a film of the same composition (PPT-1335) showed ∼5% of Tf release within 24 h. Moreover, in vivo bio-efficacy studies suggested the mortality of mosquitoes was about 50% with PP-133, which was further increased to 100% within 12 h in the presence of Tf (PPT-1335). However, 60% mortality of mosquitoes was observed with the film of PPT-1335. Hence, the nanofiber mat showed better efficacy against mosquitoes as compared to the film of the same composition. The degradation studies under various conditions revealed biocompatibility of the developed nanofiber mats with the ecosystem.

Electrospun nanofiber mats immobilized with transfluthrin to control mosquitoes.

Design, development and assessment of an essential oil based slow release vaporizer against mosquitoes

Mosquitoes (Diptera; Culicidae) are a biting nuisance and are of economic and health importance, especially for people living in tropical countries like India. Given the environmental concerns and health hazards of synthetic insecticides, development of natural products for the control of mosquito and mosquito-borne diseases are needed. In view of this, an essential oil based novel liquid vaporizer formulation with citronella and eucalyptus oils has been developed using a computer aided Artificial Neural Network and Particle Swarm Optimization (ANN-PSO) algorithm approach, aiming to predict the best optimized formulation (OF). Following the development, OF was characterized by Fourier Transform-Infra Red (FT-IR) spectroscopy and gas chromatography-mass spectroscopy (GC-MS). The efficacy of the OF was assessed against two major mosquito vectors viz. Anopheles stephensi and Aedes albopictus using a Peet-Grady chamber. Finally, toxicological impacts of the OF following its inhalation were investigated as per the Organization for Economic Co-operation and Development (OECD) guidelines. The results revealed all the ideal characteristics of the OF which were found to provide a slow release of up to 450 h at room temperature. Most importantly, the OF, exhibited 50% mosquito knock down (KT₅₀) within 11.49±1.34 and 14.15±2.15 min against An. stephensi and Ae. albopictus respectively. Toxicity assessment showed a non toxic nature of the OF following inhalation. Thus the present development would be beneficial for controlling both An. stephensi and Ae. albopictus without any associated health hazards.

Pyrethroid-Induced Organ Toxicity and Anti-Oxidant-Supplemented Amelioration of Toxicity and Organ Damage: The Protective Roles of Ascorbic Acid and α-Tocopherol

The pyrethroid toxicants, fatal at high doses, are found as remnants of crop pesticides and ingredients of commercially available insecticides. The toxic effects of high-content insecticidal pyrethroid formulations are available in 0.05 g, 1.17 g, and 0.04 g pyrethroid-instilled products, namely burning coils, pyrethroid-soaked mats, and liquid formulations of pyrethroids that release pyrethroid vapor/smoke upon heating. They provided 5.46 g/kg, 21.15 g/kg, and 4.24 g/kg of toxicants to the experimental animals over a total of 3 weeks/5 h per os (p.o.) administration, producing necrosis, hyperemia, and fatty changes in the liver; fiber separation in cardiac muscles; atrophy, lymphatic infiltration, blood vessel congestion, and hyperemia in the heart tissues of the experimental animals. The glomerular tuft necrosis, cytoplasmic degeneration of renal tubular cells, necrotic tubules, congestion, and dilatation of blood vessels were observed in the kidney tissue of intoxicated animals. Air-space enlargement, interstitial inflammation, lymphocyte infiltration aggregates, connective tissue infiltration by inflammatory cells, and hyperemia were found in the lung tissues. The pyrethroid toxicants also produced nervous tissue degeneration and decreased neurons in the brain, which were observed through histopathological examinations of the brain, lungs, heart, kidneys, and liver. The protective effects of ascorbic acid (AA/vitamin C) and α-tocopherol (E307/vitamin E) at 100 mg/kg oral doses administered daily for the entire period of the toxicant exposure of three weeks to the experimental mice, aged between 3-4 months and weighing ≈30 g, ameliorated the tissue damage, as observed through the histopathological examinations. The ascorbic acid caused recovery of the liver, kidney, brain, and heart tissue damage, while α-tocopherol was effective at ameliorating the damage in the kidneys and lung tissue compared with the control groups. The high levels of tissue damage recovery suggested a prophylactic effect of the concurrent use of ascorbic acid and α-tocopherol for the subjects under the exposure of pyrethroids.

Vitamin E ameliorates testicular histological features and androgen binding protein levels in testicle of rats induced by allethrin

Objective:

This study aims to determine the ameliorative effect of vitamin E (vit E) on histological features and androgen binding protein (ABP) levels in rats induced by allethrin.

Materials and Methods:

Thirty sexually mature male Wistar rats weighing between 200 and 300 gm, and aging 3 months were taken for this study and were divided into three groups: negative control (NC), positive control (PC), and treatment (T) groups. The PC and T groups were induced by allethrin 12 h per day for 31 days; however, only the T group was given vit E orally at 1 ml/gm body weight (BW) each day for 14 days. The paraffin block method was used to measure tubules’ diameter, thickness of the seminiferous epithelial layer, and Sertoli cell number. The ABP levels were measured by enzyme-linked immunosorbent assay.

Results:

The results showed that vit E gave significant effect (p < 0.05) on tubular diameter at NC 123.67 ± 12.77, PC 147.16 ± 10.64, and T 130.08 ± 10.00; tubular epithelial thickness at NC 33.55 ± 3.21, PC 30.02 ± 1.53, and T 32.96 ± 2.81; Sertoli cells number at NC 55.48 ± 5.9, PC 43.84 ± 3.77, and T 53.44 ± 4.26; and ABP levels at NC 72.35 ± 39.06, PC 38, 48 ± 18.78, and T 86.10 ± 35.77, respectively.

Conclusion:

This study concludes that vit E has an ameliorative effect against the toxic effects of allethrin at testicular histological features and ABP levels.