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Background: Visceral leishmaniasis (VL), known as Kala-azar on the Indian subcontinent, is a parasitic disease caused by the flagellated protozoa Leishmania donovani and can be fatal if left untreated. The sand fly Phlebotomus argentipes is the only proven vector of VL in the Southeast Asia region, and VL control in this region has relied on the use of synthetic insecticides for indoor residual spraying (IRS). The use of DDT in VL control programmes has led to the development of resistance to this insecticide in sand flies, resulting in DDT being replaced with the insecticide alpha-cypermethrin. However, alpha-cypermethrin has a similar mode of action as DDT and, therefore, the risk of resistance development in sand flies increases under the pressure of regular exposure to this insecticide. In the present study we assessed the susceptibility status of wild-caught sand flies and F1 progeny using the CDC bottle bioassay. Methods: Sand flies were collected from 10 villages in Muzaffarpur District, Bihar, India. Eight of these villages are receiving continuous IRS with alpha-cypermethrin, one village had discontinued IRS with alpha-cypermethrin and one village had never received IRS with alpha-cypermethrin. The collected sand flies were exposed to a pre-determined diagnostic dose for a specific time duration (3 µg/ml for 40 min), and knockdown and mortality at 24 h post-exposure were recorded. Results: Knockdown ranged from 91.19% to 99.47% for wild-caught sand flies and from 91.70% to 98.89% for their F1 progeny. At 24 h post-exposure, mortality ranged from 89.34% to 98.93% for wild-caught sand flies and from 90.16% to 98.33% for F1 progeny. Conclusions: The results of this study showed that P. argentipes is potentially developing resistance, signalling the need for continuous monitoring and vigilance to sustain the validation of elimination once achieved. [ABSTRACT FROM AUTHOR]

Pyrethroid insecticides are commonly used insecticides. This study was undertaken to characterize the clinical profile and outcome of deliberate self-harm (DSH) with type 1 and type 2 pyrethroids and identify factors associated with need for hospitalization. This retrospective study was conducted in a tertiary care hospital in South India to study the clinical features, treatment, and outcome of patients with pyrethroid poisoning due to DSH. Patients were categorized as poisoning with type 1 or type 2 pyrethroid compounds. Factors associated with need for hospital admission was explored using bivariate and multivariate regression analysis and expressed as odds ratio (OR) with 95% confidence intervals (CIs). A total of 379 patients presented with pyrethroid poisoning; 202 (53.3%) patients were male. The median (interquartile range) age was 26 (22–33) years. Transfluthrin (n = 48, 58%) and cypermethrin (n = 149, 50%) were the most frequently implicated type 1 compounds and type 2 compounds, respectively. Of the 130 (34.3%) patients who were admitted, 13 (3.4%) patients required mechanical ventilation. All patients survived. On multivariate logistic regression analysis, ingestion of type 2 pyrethroids (OR: 2.55, 95%CI: 1.31–4.97), history of seizures (OR: 2.62, 95%CI 1.06-6.48), and treatment prior to presentation to the referral hospital (OR: 2.99, 95%CI: 1.87–4.74) were associated with the need for hospitalization. A third of patients with pyrethroid poisoning require hospitalization. Type 2 pyrethroid poisoning is more frequent in clinical practice. Ingestion of type 2 pyrethroids, seizures, and need for pre-hospital treatment are associated with hospitalization. [ABSTRACT FROM AUTHOR]

Cypermethrin, a synthetic pyrethroid, is a widely employed pesticide in large-scale commercial agriculture and domestic settings to control pests and boost crop yields. Despite its effectiveness in controlling pests, concerns persist about the potential ecological and human health impacts associated with its use. In the present study, the impact of cypermethrin on different parameters, including growth indices, pollen morphology and pollen fertility, chlorophyll and carotenoid content, hydrogen peroxide (H2O2) scavenging, lipid peroxidation (MDA concentration), superoxide dismutase (SOD), and catalase (CAT) activities, was investigated in Cicer arietinum L. The results showed that plants exhibited decreasing trends in plant height, number of branches, pods, and seeds per plant as cypermethrin concentrations increased. These changes resulted in significant reductions in the overall yield of the plants. The percentage of wrinkled pollen significantly increased with higher concentrations of cypermethrin and longer exposure durations. Exposure to cypermethrin showed significant variations in pollen fertility of C. arietinum at different concentrations and time intervals in comparison to control, which had a baseline pollen fertility of 79.12% ± 4.59. Chlorophyll and carotenoid content of C. arietinum were considerably affected by cypermethrin, indicative of potential disturbances in essential photosynthetic processes crucial for plant health. Further, with increasing concentrations of cypermethrin ranging from 100 mg/L to 500 mg/L, noticeable effects were observed on H2O2− scavenging, MDA concentration, SOD and CAT activities of C. arietinum in dose-dependent manner. Further, it was found that the duration of exposure and concentration of cypermethrin played a crucial role in exacerbating these detrimental effects. The findings of the present study raise concerns regarding the harmful effects of agricultural pesticides like cypermethrin and highlight the need for more research on the nutritional value of products derived from plants and seeds exposed to these agents. [ABSTRACT FROM AUTHOR]

Background: One bioassay for detecting acaricide resistance in livestock ticks is the adult immersion test (AIT), wherein engorged ticks are briefly immersed into a solution of a particular acaricidal compound and examined for mortality, their egg-laying capacity and offspring hatchability in vitro. Usually, the recommended label dose or an established discriminating dose of an acaricide is used to determine high mortality (≥ 95%) of susceptible tick strains. Such a test intends to detect the presence of resistance in a tick population. However, the adult immersion test does not directly translate the bioassay results to the predicted efficacy in the field. In this paper, we used the AIT as an initial screening bioassay supplemented with the resistance intensity test (RIT), a novel larval-based bioassay, wherein the resistance level can be determined and translated to the expected field efficacy. This was done by adopting World Health Organisation (WHO) guidelines for resistance detection in mosquitoes, which combines a 1 × recommended dose with 5 × and 10 × concentrated doses to reveal low, moderate and high resistance intensity, respectively. Methods: Engorged Rhipicephalus microplus ticks were collected from cattle at six different ranches across Rio Grande do Sul, Brazil, as part of the state's acaricide resistance surveillance program. Groups of adult ticks from each field collection were subjected to the AIT from each field sample. Additionally, engorged female ticks from each ranch were allowed to lay eggs, and their larval progeny aged 14 to 28 days were then used in the RIT. Deltamethrin and a combination of cypermethrin, chlorpyrifos and piperonyl butoxide were used in both tests, and the results were statistically analysed. Results: The in vitro efficacy of deltamethrin against adult ticks in the AIT ranged between 8.74% and 25.38%. The corresponding RIT results on their larval progeny indicated a high resistance level. In the immersion test, the in vitro efficacy of the combination of cypermethrin, chlorpyrifos, and piperonyl butoxide against adult ticks ranged between 49.31% and 100%. The corresponding RIT results on their larval progeny indicated a similar response ranging from fully susceptible to low or moderate resistance. The Pearson correlation coefficient (r = 0.883) showed a high correlation between tick mortality at the 1 × recommended concentrations of acaricides in both tests. Conclusions: The resistance intensity test is a valuable addition to the range of bioassays currently available for detecting acaricide resistance by determining the level of acaricide resistance. This is relevant to whether or not to continue using a particular acaricidal class for controlling cattle ticks. [ABSTRACT FROM AUTHOR]

Cypermethrin is a pyrethroid insecticide used in aquaculture farms against ectoparasites. The conventional pesticide formulations are now being found to be greatly ineffective at low dosages, and their indiscriminate usage may cause undesired effects in ecosystems. So, the current study was designed to develop a nanoformulation of cypermethrin that would have many advantages over conventional pesticide formulations, and the toxic effects of this formulation were then tested on the carp Labeo rohita fingerlings. The 96-h LC50 was estimated at 0.018 mg L−1 after the acute toxicity study. Chronic toxicity studies were carried out, exposing the fish to two sublethal doses via 1/10th (C1) and 1/50th (C2) of 96-h LC50 for a period of 45 days. The nanoformulation exposure caused a significant reduction in the brain AChE enzyme activity. Catalase and glutathione-s-transferase enzyme activity in the gills and liver increased significantly, as did superoxide dismutase enzyme activity in the kidney. Serum total protein, triglycerides, cholesterol, and some serum enzyme activities decreased. In contrast, white blood cells, red blood cells, haemoglobin, and hematocrit levels decreased only in fish exposed to a higher dose. As baseline information, these findings may aid in understanding the toxic effect of nanoformulated cypermethrin on finfish. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION Pediococcus acidilactici is an effective adsorbent for removing of pyrethroid insecticides. This study investigated the biosorption characteristics and mechanisms of P. acidilactici D15 using adsorption measurement, scanning electron microscopy, and Fourier‐transform infrared spectroscopy. Isotherm and kinetic models were used to analyze the biosorption process.The Langmuir isotherm model best described the cypermethrin biosorption process, with the maximum adsorption capacity of P. acidilactici D15 being 21.404 mg/g. The biosorption appeared to involve monolayer coverage with uniform forces. The pseudo‐second‐order model also fits well. The rate‐controlling steps involved intraparticle diffusion, film diffusion and chemosorption. The main cellular components involved in cypermethrin biosorption were exopolysaccharides, spheroplast, and cell wall, especially peptidoglycan. The functional groups (–OH, –NH, –CH3, –CH2, –CH, –CONH–, –CO, and –C–O–C–) from proteins, polysaccharides, and peptidoglycan on the cell surface likely played a role in binding cypermethrin. Additionally, P. acidilactici D15 effectively reduced cypermethrin in pickle wastewater.These findings suggest that P. acidilactici D15 could be a potential agent for reducing pesticide residues, laying the groundwork for treating pickle wastewater containing such pesticide residues. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Simple Summary: Insecticides, while boosting crop yields, can harm non-target insects like Vespa magnifica. This study explored the effects of four common insecticides: thiamethoxam, avermectin, chlorfenapyr, and β-cypermethrin, on Vespa magnifica. Although larval survival was unchanged, pupation and fledge rates dropped significantly. Enzyme assays showed stress responses with increased antioxidant activity and suppressed peroxidase levels. Transcriptomic analysis revealed heightened energy expenditure, impacting essential functions like flight and immunity. Key pathways related to metabolism and nervous system activity were also affected, potentially impairing learning, memory, and detoxification. These results highlight the broader ecological risks of insecticide exposure, emphasizing the need for better strategies to protect beneficial insect populations. Insecticides are widely used to boost crop yields, but their effects on non-target insects like Vespa magnifica are still poorly understood. Despite its ecological and economic significance, Vespa magnifica has been largely neglected in risk assessments. This study employed physiological, biochemical, and transcriptomic analyses to investigate the impact of sublethal concentrations of thiamethoxam, avermectin, chlorfenapyr, and β-cypermethrin on Vespa magnifica. Although larval survival rates remained unchanged, both pupation and fledge rates were significantly reduced. Enzymatic assays indicated an upregulation of superoxide dismutase and catalase activity alongside a suppression of peroxidase under insecticide stress. Transcriptomic analysis revealed increased adenosine triphosphate-related processes and mitochondrial electron transport activity, suggesting elevated energy expenditure to counter insecticide exposure, potentially impairing essential functions like flight, hunting, and immune response. The enrichment of pathways such as glycolysis, hypoxia-inducible factor signaling, and cholinergic synaptic metabolism under insecticide stress highlights the complexity of the molecular response with notable effects on learning, memory, and detoxification processes. These findings underscore the broader ecological risks of insecticide exposure to non-target insects and highlight the need for further research into the long-term effects of newer insecticides along with the development of strategies to safeguard beneficial insect populations. [ABSTRACT FROM AUTHOR]

We investigate role of ATP sensitive potassium (KATP) channel in cytotoxic effect of cypermethrin on rat aortic smooth muscle cells. Cytotoxicity analysis was performed at 0, 0.1, 0.5, 10, 50, and 100 µM concentrations of cypermethrin and the cell index (CI) was calculated. KATP currents were recorded using patch clamp technique for 50 and 100 µM concentrations and channel conductivity was determined by obtaining current-voltage characteristics. No cytotoxic effect was observed in the first 72 hours. At the 96th hour, only at 100 µM concentration, the CI value decreased significantly compared to control group and at 120 and 144th hours, it was observed that the CI value decreased significantly at all concentrations. Currents and conductivities were significantly decreased at 50 and 100 µM concentrations. Results gave clues that cypermethrin causes a cytotoxic effect on vascular smooth muscles and that KATP channels may have a role in the emergence of this effect. [ABSTRACT FROM AUTHOR]

Developmental exposure to carbamates, organophosphates, and pyrethroids has been associated with impaired neurodevelopmental outcomes. Sex-specific differences following chronic insecticide exposure are rather common in vivo. Therefore, we assessed the chronic effects of in vitro exposure to different carbamates (carbaryl, methomyl and aldicarb), organophosphates [chlorpyrifos (CPF), chlorpyrifos-oxon (CPO), and 3,5,6,trichloropyridinol (TCP)], and pyrethroids [permethrin, alpha-cypermethrin and 3-phenoxy benzoic acid (3-PBA)] on neuronal network development in sex-separated rat primary cortical cultures using micro-electrode array (MEA) recordings. Our results indicate that exposure for 1 week to carbaryl inhibited neurodevelopment in male cultures, while a hyperexcitation was observed in female cultures. Methomyl and aldicarb evoked a hyperexcitation after 2 weeks of exposure, which was more pronounced in female cultures. In contrast to acute MEA results, exposure to ≥ 10 µM CPF caused hyperexcitation in both sexes after 10 days. Interestingly, exposure to 10 µM CPO induced a clear hyperexcitation after 10 days of exposure in male but not female cultures. Exposure to 100 µM CPO strongly inhibited neuronal development. Exposure to the type I pyrethroid permethrin resulted in a hyperexcitation at 10 µM and a decrease in neuronal development at 100 µM. In comparison, exposure to ≥ 10 µM of the type II pyrethroid alpha-cypermethrin decreased neuronal development. In female but not in male cultures, exposure to 1 and 10 µM permethrin changed (network) burst patterns, with female cultures having shorter (network) bursts with fewer spikes per (network) burst. Together, these results show that MEA recordings are suitable for measuring sex-specific developmental neurotoxicity in vitro. Additionally, pyrethroid exposure induced effects on neuronal network development at human-relevant concentrations. Finally, chronic exposure has different effects on neuronal functioning compared to acute exposure, highlighting the value of both exposure paradigms. [ABSTRACT FROM AUTHOR]

Pyrethroids are widely used insecticides with huge applications for household as well as agricultural purposes and contribute to improved product quality and higher yields. In recent decades, the demand for pyrethroids has increased significantly due to advantages such as broad-spectrum efficacy, high insecticidal potential, and lower pest resistance. However, several studies have suggested that human exposure to pyrethroids leads to reproductive problems. Sex hormone-binding globulin (SHBG) is an important hormone transport protein regulating the availability of steroids at their target site. The aim of our study was to investigate the structural interactions of commonly used pyrethroids, cypermethrin and deltamethrin, with ligand binding pocket of SHBG. Cypermethrin and deltamethrin were docked into the steroid binding pocket of SHBG using Schrodinger's induced fit docking (IFD) followed by molecular dynamics (MD) simulation studies. The resultant SHBG-pyrethroid complexes from IFD experiments were subjected to structural analysis including the molecular interactions followed by binding energy estimation. The analysis revealed that both the ligands were tightly bound in the SHBG pocket with high percentage of commonality among the SHBG residues between the indicated pyrethroid ligands and the SHBG native ligand, dihydrotestosterone (DHT). The estimated binding energy values for cypermethrin were less but close to the values calculated for the SHBG native ligand, DHT. However, the estimated binding energy values for deltamethrin were higher compared to the values calculated for SHBG native ligand, DHT. Furthermore, the MD simulation results also revealed the higher stability of SHBG-deltamethrin than SHBG-cypermethrin complex. To sum up, the results suggested that deltamethrin has a greater capability than cypermethrin to prevent sex steroid hormone from binding to SHBG, even though both pyrethroids have this ability. Consequently, this might hamper the circulatory transport of sex steroid hormones and their availability at the target site, subsequently interfering with reproductive function. [ABSTRACT FROM AUTHOR]

Background: Studies evaluating the attrition, physical and insecticidal durability of dual active ingredient (AI) insecticide-treated nets (ITNs) are essential for making programmatic decisions regarding their deployment. We performed a prospective study embedded in a cluster randomised controlled trial (cRCT) to evaluate the attrition, fabric integrity and insecticidal durability of Interceptor® G2 (alpha-cypermethrin-chlorfenapyr) and Royal Guard® (alpha-cypermethrin–pyriproxyfen), compared to Interceptor® (alpha-cypermethrin) in Benin. Methods: A total of 2428 study nets in 1093 randomly selected households in five clusters per arm of the cRCT were monitored for ITN attrition and fabric integrity every 6–12 months post-distribution. Householders were further surveyed to investigate non-study net use and their preference for ITN fabric types used in the study nets. A second cohort of 120 nets per ITN type were withdrawn every 12 months and assessed for chemical content and insecticidal activity in laboratory bioassays. Alpha-cypermethrin bioefficacy was investigated using the susceptible Anopheles gambiae Kisumu strain, and chlorfenapyr and pyriproxyfen bioefficacy were investigated using the pyrethroid-resistant Anopheles coluzzii Akron strain. Net pieces were tested in WHO cone bioassays and tunnel tests for alpha-cypermethrin and in tunnel tests for chlorfenapyr; pyriproxyfen activity was assessed in cone bioassays as the reduction in fertility of blood-fed survivors using ovary dissection. Bioefficacy was expressed as the proportion of ITNs passing predetermined WHO criteria, namely knock-down ≥ 95% or 24/72 h mortality ≥ 80% or reduction in fertility ≥ 50%. Results: Overall ITN survivorship was 52% at 24 months and fell to 15% at 36 months. Median ITN survival time was lower with Royal Guard® relative to Interceptor® [1.6 vs 2.3 years; hazard ratio (HR) 1.49, 95% confidence interval (CI) 1.36–1.66; p < 0.001] and Interceptor® G2 (1.6 vs 2.1 years; HR 1.33, 95% CI 1.20–1.47; p < 0.001). Householders overwhelmingly preferred polyester nets over polyethylene nets (96%), and more Royal Guard® nets were replaced with spare polyester nets from previous campaigns. All Royal Guard® nets passed efficacy criteria for alpha-cypermethrin at all time points (100%) while ITN pass rates after 24 months had fallen to < 40% for pyriproxyfen and chlorfenapyr. The chemical content analysis showed a higher loss rate of the non-pyrethroid insecticides relative to the pyrethroids in each dual ingredient AI ITN; 74% vs 47% for Royal Guard® and 85% vs 63% for Interceptor® G2 at 36 months. Conclusions: The median ITN survival time for Interceptor® G2 (2.1 years) and Royal Guard® (1.6 years) in Benin is substantially lower than 3 years. Royal Guard® nets were discarded more quickly by householders, partly due to their low preference for polyethylene nets. The insecticidal activity of the non-pyrethroid insecticides in both dual AI ITNs was short-lived compared to alpha-cypermethrin. The results corroborate the findings from the cRCT conducted in Benin. [ABSTRACT FROM AUTHOR]

Background and Objective: The presence of pesticides in milk and dairy products poses a potential risk to consumers. The current study aimed to determine the concentrations of diazinon and cypermethrin in milk, cheese, and butter distributed in Gonbad-Kavus City. Materials and Methods: A total of 50 samples including raw milk, pasteurized milk, ultra-high-temperature milk, traditional cheese, and traditional butter, were randomly collected from supply centers in Gonbad-Kavus from between 2021 and March 2022. The concentrations of diazinon and cypermethrin in the samples were measured using highperformance liquid chromatography (HPLC). Results: The mean diazinon levels in raw milk, pasteurized milk, and ultra-high-temperature milk samples were 41.91 ± 9.68, 28.07 ± 5.86, and 40.21 ± 9.52 µg/kg, respectively. The mean cypermethrin levels in raw milk, pasteurized milk, and UHT milk samples were 34.06 ± 8.20, 22.63 ± 5.88, and 29.82 ± 8.09 µg/kg, respectively. Significant differences were observed among the sample types for both diazinon and cypermethrin levels. In cheese samples, the mean diazinon and cypermethrin levels were 57.23 ± 10.59 and 38.12 ± 8.69 µg/kg, respectively. In butter samples, the mean diazinon and cypermethrin levels were 16.77 ± 4.15 and 17.50 ± 6.47 µg/kg, respectively. Conclusion: The results of the present study showed that the various types of milk distributed across Gonbad-Kavus contain excessive diazinon residues, while the residual cypermethrin levels were below the allowable limit. Therefore, a codified program to reduce diazinon the residuals in milk, cheese, and butter distributed in Gonbad-Kavus should be implemented. [ABSTRACT FROM AUTHOR]

The extensive utilization of chlorpyrifos and cypermethrin in agriculture raises concerns regarding the accumulation of pesticide residues in human food, posing a threat to human health. This study aimed to investigate the effect of ozonation on cauliflower to decrease the level of pesticides. Cypermethrin and organophosphate chlorpyrifos were applied to cauliflower at specific doses. High-performance liquid chromatographic techniques were employed to detect pesticide residues in cauliflower. The effects of common oxidizers (hydrogen peroxide, chlorine, and ozone) on the reduction of pesticide residues were investigated. Solutions of hydrogen peroxide (10 and 100 ppm), chlorine (10 and 100 ppm), and ozone (10 and 100 ppm) were prepared, and the cauliflower sample was immersed for 20 min. The immersion in 10 ppm hydrogen peroxide solution reduced chlorpyrifos and cypermethrin by 68 and 65%, respectively. Meanwhile, at 100 ppm hydrogen peroxide solution, the reduction rates of chlorpyrifos and cypermethrin residues were 72 and 75%, respectively. Immersion in ozone solution at 10 ppm concentration reduced chlorpyrifos and cypermethrin by 58 and 57%, respectively. At 100 ppm ozone, chlorpyrifos was reduced up to 64%, and cypermethrin reduction was 74%. Chlorine immersion at 10 ppm reduced chlorpyrifos residues by 68% and cypermethrin residues by 81%, while a 100 ppm chlorine solution reduced chlorpyrifos residues by 100% and cypermethrin residues by 84%. From these results, it was concluded that chlorine was the most effective of all the cleaning solutions to remove pesticides from vegetables. [ABSTRACT FROM AUTHOR]

Background: German cockroaches are the most common cockroach species in the world. Although German cockroach infestations occur in many human-inhabited spaces, they are most commonly associated with restaurants, food processing facilities, hotels, nursing homes. It's also carried viruses, protozoa and infectious bacteria on the outside and inside of body surfaces and play a role in causing dizziness, asthma and nausea reactions in people. So, Blattella germanica is considered as an important medical and economic. Methods: This study aimed to evaluate the efficacy of Nerium oleander extract against cockroaches and inhibition hatching eggs in vitro using a dipping method test. Two graduated concentrations of extract (50 and 100 mg/ml) were tested at different periods and changes over time in the viability of cockroaches were registered for (1 and 2 hours) and in relation to Inhibition hatching eggs after 30 days. Distilled water and cypermethrin (0.1%) were used as negative and positive control, respectively. A chemical assay was performed by FT-IR to investigate the presence of several anticipated active chemical compounds in Nerium oleander leaf extract. Result: The analysis of phytochemicals by FT-IR for alcoholic extracts of Nerium oleander extracts revealed the presence of 12 effective chemical ingredients such as carbohydrates, alkaloids, flavonoids, glycosides and tannins. The results showed that the extract had high efficacy in killing Cockroaches that were exposed to a high concentration of extract (100 mg/mL), the mortality rate was (90 and 100%), compared to the (cypermethrin 0.1%), the mortality rate was (70 and 100%) during the periods (1 and 2 hr) respectively. While the eggs cockroaches that were exposed to concentration of extract (100 mg/mL) and positive control (cypermethrin 0.1%) the hatching rate was (60 and 60%) after 30 days period respectively. While the negative control (without treated) was the hatching eggs cockroaches rate is (100%) during that period. [ABSTRACT FROM AUTHOR]

Ips typographus (L.) is the most significant insect pest in the European spruce forests. Methods of control and monitoring are in the period of Ips typographus (L.) outbreaks supplemented with suppressive procedures applying insecticides. The aim of our study was to determine the necessary length of Ips typographus (L.) imagoes movement across the treated surface, resulting in their death also in the case of their flying away from the trap tree. Insecticides Forester (active substance cypermethrin) and Dinastia (active substance deltamethrin) were tested in laboratory conditions. Exposure times the beetles moved on the intoxicated bark were 30–300 s. Then the beetles were placed in Petri dishes and their survival rate up to twenty-four hours was established. Experiment duration was 8 weeks from spraying with repeated week control tests. High efficiency of tested pyrethroids ensuring the death of also flying away imagoes within six hours after contamination was established at three weeks. The rate of their survival was increasing from Week 4 independently on the exposure times (deltamethrin). In cypermethrin, the survival rate of imagoes was high and dependent on the exposure times. The efficiency of deltamethrin was higher than that of cypermethrin. During the outbreaks, the pheromone-baited poisoned trap trees causing the death also to flying away imagoes of Ips typographus (L.) have to be sprayed with the above-mentioned pyrethroids in a monthly interval at the time of swarming culmination. The efficiency of both insecticides decreased more rapidly on the upper unprotected side of the trap tree. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigated the behavioral asymmetries and mating success of Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) under sublethal exposures to α-cypermethrin. Control males exhibited a right-side bias, which increased the likelihood of successful copulation, especially when head butts preceded mounting. A similar pattern was observed for LC10-exposed males, though their success rate slightly declined. In females, the right-side approach also enhanced copulation success. The direction of approach and mounting influenced the time required for key mating behaviors like mate detection and mounting. Males exposed to LC30 of α-cypermethrin needed a longer time for mate detection compared to control and LC10, especially when approaching from the back or front side. Females of the LC30 group were also influenced, with shorter copulation times when approaching from the right. These findings demonstrate that α-cypermethrin affects both mating success and the duration of related behaviors. Sublethal exposure to insecticides can adversely impact various biological and behavioral characteristics of insects. Although α-cypermethrin has been previously tested for its effects on control of Alphitobius diaperinus, there is no knowledge about the effect of this insecticide on its behavioral asymmetries and mating success. Μales at all exposures (control, LC10, and LC30), that first approached their mate, showed right-biased tendency (approached their mate from their right side) in mate recognition. Females, however, showed variation in this behavior between the three exposures. Right-biased tendency of males in all treatment scenarios led to a higher percentage of successful copulations compared to the three other directions. For males that first approached their mate, the insecticide did not affect their lateralization of the first approach but did affect their copulation success. The duration of copulation time was reduced after the exposure to the insecticide, with the longest duration noted in the control females (63.0 s) and the lowest in the α-cypermethrin LC30 females (46.9 s). Moreover, at the α-cypermethrin LC10 exposure, mate recognition time was reduced, as opposed to α-cypermethrin LC30 exposure where mate recognition time was increased. These results can be further utilized to uncover the behavioral impacts of insecticides, enhancing the effectiveness of pest management in warehouses and poultry production facilities. [ABSTRACT FROM AUTHOR]

Ticks pose a significant threat due to their ability to lay thousands of eggs, which can persist in the environment for extended periods. While the impact of various compounds on adult and larval ticks has been studied, research on their efficacy against tick eggs is limited. This study evaluated the ovicidal activity of commercial acaricides, disinfectants, and natural products against Rhipicephalus annulatus eggs using the egg hatch assay (EHA). Deltamethrin and cypermethrin caused a non-significant inhibition of hatching (IH%), even at concentrations higher than the recommended levels. By contrast, the acaricides chlorpyrifos, phoxim, and amitraz significantly inhibited hatching at all tested concentrations. Ivermectin also demonstrated significant IH% at various concentrations but did not fully inhibit the hatching process. Among the disinfectants tested, Virkon-S®, TH4, and Chlorox showed insignificant effects, whereas formalin achieved an IH% of only 34.1% at a high concentration of 200 mg/mL. Natural products, carvacrol and thymol, exhibited significant ovicidal activity, with a significant IH%. In a semi-field application, phoxim (0.5 mg/mL) and deltamethrin (0.05 mg/mL) were sprayed on tick eggs on pasture soil from a farm. The results indicated that phoxim-treated eggs had a 40% IH%, while deltamethrin-treated eggs showed only an 8.79% IH%. In conclusion, the acaricides amitraz, phoxim, and chlorpyrifos, as well as the natural products carvacrol and thymol, caused significant toxicity to R. annulatus eggs. [ABSTRACT FROM AUTHOR]

Cypermethrin, a Class II pyrethroid pesticide is well-documented for its toxicity to non-target organisms. Its environmental breakdown and the resulting harmful effects in various species have been widely researched because of its high toxicity. In this context, the present study aimed to evaluate the acute toxicity of cypermethrin (25% EC) on juvenile Cyprinus carpio, var. communis. Juvenile fish, each weighing 12±2 grams were used for the study. Initial range-finding tests were followed by definitive tests, and the acute toxicity data was analyzed using Finney's Probit Method. The 96-hour LC50 for Cyprinus carpio was determined to be 1.239 µg/L in a static bioassay setup. The mean values of the physicochemical parameters of the aquarium water measured during the bioassay showed slight variations, indicating that fish mortality was due to pesticide exposure rather than suffocation. The average laboratory temperature was recorded at 17°C, while the water temperature was measured at 12°C. The mean dissolved oxygen levels were 6 mg/L and the pH was 7.5. Total dissolved solids were 4.0 × 10³ mg/L and CO2 levels remained constant at 1.2 mg/L. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mortality caused by various pyrethroids, and neonicotinoids has been studied for stored‐product insects in the past, yet limited information exists on the sublethal effects they can induce to Oryzaephilus surinamensis. In the current study, the sublethal effects of deltamethrin, λ‐cyhalothrin, α‐cypermethrin, etofenprox, and the mixture of acetamiprid with d‐tetramethrin and piperonyl butoxide on the mobility of O. surinamensis in the presence or the absence of a food source was investigated. RESULTS: Lethal concentrations (LCs) were lower for deltamethrin, α‐cypermethrin, and λ‐cyhalothrin (LC10 = 0.000233, 0.000211, and 0.000271 mg active ingredient (a.i.) cm−2, LC30 = 0.000413, 0.000398, and 0.000447 mg a.i. cm−2, respectively), followed by etofenprox, and the mixture of acetamiprid with d‐tetramethrin and piperonyl butoxide (LC10 = 0.00228 and 0.003267 mg a.i. cm−2, LC30 = 0.00437 and 0.01188 mg a.i. cm−2, respectively). Deltamethrin and λ‐cyhalothrin negatively impacted adult walking behavior, increasing stop durations compared to controls. Adults exposed to LC10 and LC30 of λ‐cyhalothrin, and LC30 of deltamethrin exhibited prolonged periods on their backs compared to the remaining treatments and the controls. The α‐cypermethrin LC30‐exposed adults exhibited significantly shorter walking and stopping durations than controls but demonstrated prolonged climbing on the arena walls compared to adults exposed to the remaining a.i. and the control. A similar trend was observed for etofenprox. CONCLUSIONS: Under sublethal concentrations, λ‐cyhalothrin and deltamethrin increased stop intervals and reduced the duration of climbing attempts of O. surinamensis versus α‐cypermethrin. These findings advance comprehension of the underexplored sublethal impacts of the tested a.i. on O. surinamensis adults, holding potential for leveraging insecticide‐induced behavioral effects to enhance warehouse pest management. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Abstract Background Exposure to chemical toxins, including insecticides, harms bodily organs like the brain. This study examined the neuroprotective of thymoquinone on the cypermethrin’s harmful effects on the histoarchitecture of the dentate gyrus and motor deficit in the dentate gyrus. Methods Forty adult male rats (180–200 g) were randomly divided into 5 groups (n = 8 per group). Groups I, II, III, IV, and V received oral administration of 0.5 ml of phosphate-buffered saline, cypermethrin (20 mg/kg), thymoquinone (10 mg/kg), cypermethrin (20 mg/kg) + thymoquinone (5 mg/kg), and cypermethrin (20 mg/kg) + thymoquinone (10 mg/kg) for 14 days respectively. The novel object recognition test that assesses intermediate-term memory was done on days 14 and 21 of the experiment. At the end of these treatments, the animals were euthanized and taken for cytoarchitectural (hematoxylin and eosin; Cresyl violet) and immunohistochemical studies (Nuclear factor erythroid 2-related factor 2 (Nrf2), Parvalbumin, and B-cell lymphoma 2 (Bcl2). Result The study shows that thymoquinone at 5 and 10 mg/kg improved Novelty preference and discrimination index. Thymoquinone enhanced Nissl body integrity, increased GABBAergic interneuron expression, nuclear factor erythroid 2-derived factor 2, and enhanced Bcl-2 expression in the dentate gyrus. It also improved the concentration of nuclear factor erythroid 2-derived factor 2, increased the activities of superoxide dismutase and glutathione, and decreased the concentration of malondialdehyde level against cypermethrin-induced neurotoxicity. Conclusion thymoquinone could be a therapeutic agent against cypermethrin poisoning.

Background: Exposure to chemical toxins, including insecticides, harms bodily organs like the brain. This study examined the neuroprotective of thymoquinone on the cypermethrin's harmful effects on the histoarchitecture of the dentate gyrus and motor deficit in the dentate gyrus. Methods: Forty adult male rats (180–200 g) were randomly divided into 5 groups (n = 8 per group). Groups I, II, III, IV, and V received oral administration of 0.5 ml of phosphate-buffered saline, cypermethrin (20 mg/kg), thymoquinone (10 mg/kg), cypermethrin (20 mg/kg) + thymoquinone (5 mg/kg), and cypermethrin (20 mg/kg) + thymoquinone (10 mg/kg) for 14 days respectively. The novel object recognition test that assesses intermediate-term memory was done on days 14 and 21 of the experiment. At the end of these treatments, the animals were euthanized and taken for cytoarchitectural (hematoxylin and eosin; Cresyl violet) and immunohistochemical studies (Nuclear factor erythroid 2-related factor 2 (Nrf2), Parvalbumin, and B-cell lymphoma 2 (Bcl2). Result: The study shows that thymoquinone at 5 and 10 mg/kg improved Novelty preference and discrimination index. Thymoquinone enhanced Nissl body integrity, increased GABBAergic interneuron expression, nuclear factor erythroid 2-derived factor 2, and enhanced Bcl-2 expression in the dentate gyrus. It also improved the concentration of nuclear factor erythroid 2-derived factor 2, increased the activities of superoxide dismutase and glutathione, and decreased the concentration of malondialdehyde level against cypermethrin-induced neurotoxicity. Conclusion: thymoquinone could be a therapeutic agent against cypermethrin poisoning. [ABSTRACT FROM AUTHOR]

In this study, the combined toxicity of cypermethrin and lead were investigated using molecular and biochemical parameters in albino mice. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP),blood urea nitrogen (BUN) and creatinine levels were studied and used as indicators of toxicity. Comet test was also utilized to evaluate the mechanism of genotoxicity of cypermethrin, lead and the ) cypermethrin and lead) group. Albino mice were divided into eight groups and given intraperitoneal cypermethrin injections at 1.75 mg/kg/day and lead nitrate at 1.75 mg/kg/day, and combined doses of each one respectively. Blood samples were collected after two and four weeks. Cypermethrin raised AST, AL, BUN and creatinine levels as treatment time and doses rose, as did lead nitrate which elevated liver and kidney parameters in response to the toxicant. As evaluated by comet test molecular characteristics, the impact of cypermethrin and lead nitrate was an increase in DNA damage. [ABSTRACT FROM AUTHOR]

The present study was conducted to evaluate the effects of exposure to sublethal concentrations of cypermethrin on growth, phenotypic traits, and metabolic and antioxidant enzymes activities of monosex tilapia (Oreochromis niloticus). The median lethal concentration (LC50) of cypermethrin was initially ascertained to be 0.04 ppm after 12 h of exposure to three concentrations (0.04, 0.20, and 1.0 ppm) via the Probit analysis method. The sublethal exposures were obtained for 3 months at 0.0016, 0.008, and 0.04 ppm of cypermethrin. The growth performance, phenotypic traits, and enzymatic activity were analyzed. The research findings revealed a notable impact of cypermethrin on the growth performance of monosex tilapia, with a significant (p < 0.05) decrease in weight observed as the concentration increased. The experiment documented a significant change (p < 0.05) in the phenotypic traits of standard length, total length, tail length, trunk length, eye diameter, body area, and color patterns, but not dressing percentage. Furthermore, it was observed that the activities of amylase and protease in both the intestine and muscle decreased significantly (p < 0.05) with increasing concentrations of cypermethrin, except for amylase in the muscle, where no significant change was noted (p > 0.05). The results also demonstrated significant reductions (p < 0.05) in the activity of metabolic enzymes, specifically superoxide dismutase and catalase, following exposure to sublethal levels of cypermethrin. The study suggested that sublethal exposure of pyrethroid alters the growth, phenotypic traits, metabolic enzymes activities, and immunity of monosex tilapia. [ABSTRACT FROM AUTHOR]

Two of the most-commonly used pyrethroid insecticides were subjected to static bioassays to determine their acute toxicity to Clarias gariepinus fingerlings, followed by comparisons of their impact on mortality and behavioural changes in the fish. The LC50 values for deltamethrin (DMT) at exposure durations of 24, 48 and 96 h were 12, 9 and 8 µg l−1, respectively; the LC50 values for cypermethrin (CYP) at the same exposure durations were 55, 44 and 26 µg l−1, respectively. The estimated safe limits ranged from 8×10−1 to 8×10−5 µg l−1 for DMT, and 26×10−1 to 26×10−5 µg l-1 for CYP. The tested substances had an acute toxicity effect on fish development as they caused death, and chronic toxicity effects as they changed fish behaviour. Fish exposed to either one of these pesticides showed behavioural alterations, such as loss of static balance, excessive mucous secretion, irregular swimming, gulping of air and skin discolouration. The results reveal that CYP was less toxic (96-h LC50 = 26 µg l−1) than DMT (96-h LC50 = 8 µg l−1) based on the greater LC50 value and a lower percentage of mortality. To avoid potential ecotoxicological risks to aquatic life, use of these pyrethroids in both terrestrial and freshwater ecosystems must be treated with caution. [ABSTRACT FROM AUTHOR]

Cypermethrin (CYP) is a synthetic pyrethroid. It acts as an endocrine disruptor which negatively affects animal's reproductive and developmental processes of progeny. So, The present study aimed to examine the toxicity of oral administration of CYP at three different doses (25mg, 50mg, and 75mg/kg) on the reproductive organs of albino rats and also on the growth and development of pups. For this study, animals were divided into four groups: Group I was the control group, and the remaining three were experimental groups that received CYP at a dose of 25mg (group II), 50mg (group III), and 75mg (group IV) per kg body weight (BW) of rat per day for 30 days. There are sixteen animals in each group-eight males and eight females. Histological studies of reproductive organs suggested that CYP exposure caused alteration in the structure of the ovary and testis tissue. In females, significant changes in the ovary, such as distorted follicles, loss of follicular stages, presence of antral follicles, damaged granulosa and theca cells, and blood vessel congestion, were observed, while in males, there were alterations in testes tissue damage in seminiferous tubules, reduced number of germinal cells, and reduction in the size of seminiferous tubules. A significant reduction was observed in the number, length, eyes opening, fur arrival time, and size of pups. Fertility was also recorded up to 80% in the 50 and 75mg CYP-treated female rats. The study suggested that CYP exposure caused gonadal toxicity in albino rats and affected the development of neonates. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the combined effects of chlorpyrifos and cypermethrin combined on dopaminergic neurotoxicity, motor behaviours and level of selected inflammatory proteins in rats compared to either alone for delineating an interaction between these two pesticides. The rotarod and grip strength tests were employed to assess neurobehavioural changes. The striatal dopamine content and expression of tyrosine hydroxylase (TH), α-synuclein, cyclooxygenase-2 (COX-2), and tumour necrosis factor-α (TNF-α) proteins in the nigrostriatal tissue were measured. Chlorpyrifos impaired the neurobehavioural indexes, reduced the striatal dopamine level, augmented the level of α-synuclein, COX-2, and TNF-α and attenuated the expression of TH similar to but a little less than cypermethrin. Half the dose of both pesticides together produced additional neurotoxicity compared with the usual (highest employed) dose of either alone. The results showed that chlorpyrifos induced moderately less dopaminergic neurotoxicity than cypermethrin. In the combination, they produced a little higher toxicity than either pesticide alone. [ABSTRACT FROM AUTHOR]

The present study was undertaken to evaluate cypermethrin (CYP)-induced oxidative stress [reactive oxygen species (ROS) and lipid peroxidation (LPO) in gills, muscles, brain, and liver tissues] and DNA damage/genotoxicity (peripheral blood erythrocytes) in a freshwater teleost rohu (Labeo rohita) and the protective role of vitamin C. The LC50 of CYP against rohu was found to be 4.5 µg/L in a semi-static culture system through probit analysis. Fingerlings of rohu were distributed into four groups (Group 1st served as a control, fed 35% protein basal diet and was not exposed to CYP; Group 2nd was fed a basal diet and exposed to CYP; Group 3rd and Group 4th were fed diets supplemented with vitamin C at the rate of 100 and 200 mg/kg diet, respectively, and exposed to CYP). Fingerlings were reared on a basal and vitamin C-supplemented diet for 28 days prior to exposure to CYP. The results indicate a time-dependent significant increase in ROS and LPO (indicated by time course increase in TBARS level) as well as DNA damage in terms of number of comets, % DNA in tail, tail moment, tail length, and olive tail moment after exposure to LC50 of CYP. However, statistically comparable results in both Groups 1st and 4th indicate the protective role of vitamin C. The results reveal the effectiveness of vitamin C as a feed additive for countering pesticides toxicity in Labeo rohita. The current study indicates CYP as a potential genotoxicant for fish and classifies SCGE as a reliable and sensitive tool for assessing DNA damage. [ABSTRACT FROM AUTHOR]

The present work proposes a spectrophotometric method for deltamethrin determination using silver nanoparticles (AgNPs). The AgNPs are spherical with a diameter of~11 nm and a negative surface charge with zeta potential ranging from −4.1 mV (pH 2) to −48 mV (pH 10). The AgNP colloidal system showed greater stability at higher pH values and for a molar ratio of 6 between the sodium borohydride and silver nitrate in the synthesis. This is because the borate ions from the oxidation of borohydride are present on the surface of the nanoparticles, promoting an electrostatic repulsion between them which keeps them dispersed. The method was validated, obtaining satisfactory results of veracity and precision, and the limits of detection and quantification were 0.17 and 0.51 mg L−1, respectively. The method was selective for deltamethrin compared to the compounds cypermethrin, endosulfan, thiamethoxam, atrazine, chlorpyrifos and parathion. Deltamethrin promotes the formation of dendritic silver nanostructures, changing the color of the system. The results demonstrate the development of a reliable and selective method for the detection of deltamethrin using AgNPs. [ABSTRACT FROM AUTHOR]

Objective: To determine the hepatotoxic effects induced by cypermethrin. The study also attempts to evaluate the hepatoprotective efficacy of Nigella sativa oil against hepatotoxicity produced by cypermethrin. Study Design: Experimental study. Setting: Department of Anatomy, Pharmacology, and Pathology of Peshawar Medical College and Animal house of PCSIR Laboratories Complex, Peshawar. Period: May 2023 to Dec 2023. Methods: Animals were divided into two groups: Control (Group A) and Experimental (Group B). The Experimental group (Group B) is divided into two subgroups Group B-I and Group B-II. Forty-two male Sprague Dawley rats were randomly assigned to three groups of fourteen rats each in order to conduct an experimental investigation. Group A served as a control group. Cypermethrin (5.5mg/kg-1 body weight) per day dissolved in corn oil was administered orally to Group B-I. Cypermethrin (5.5 mg/kg-1 body weight) per day orally and (1ml/kg-1 body weight) per day of Nigella sativa oil were given to group B-II. Liver obtained from these groups were fixed for histological studies under light microscopy. Liver tissues of the cypermethrin-treated animals showed leucocytic infiltration, hydropic alterations such as ballooning degeneration and focal lytic (spotty) liver necrosis. Results: After four weeks of treatment with cypermethrin demonstrated significant liver damage in group B-I animals. In group B-II Nigella sativa oil significantly reduced hepatotoxicity and induced regenerative changes. Nigella sativa oil demonstrated protection against the cypermethrin and preserved the normal histological architecture of the liver. Conclusion: Cypermethrin had a hepatotoxic potential and caused hepatotoxicity in liver, as evidenced by the histological changes in the liver tissue. However, the study also found that Nigella sativa oil showed a better hepatoprotective effect, as it was able to effectively reverse the liver damage caused by both cypermethrin. [ABSTRACT FROM AUTHOR]

One method of crop protection is the application of a widely used group of pesticides—pyrethroids. As xenobiotics, sub-lethal doses of insecticides cause stress in pests, resulting in a change in the shape and size of their organs or bodies. The stress caused by pesticides may lead to acute destabilization of development, but also to transgenerational canalization through the process of genetic assimilation. Fluctuating asymmetry (FA), small random deviations between the right and left sides of bilaterally symmetrical traits, is an outcome of developmental instability and is a measurable indicator of phenotypic response to stress. We exposed four populations of the seed beetle Acanthoscelides obtectus to sub-lethal doses of cypermethrin for ten generations in a laboratory evolution experiment. Using geometric morphometrics, we analyzed size and shape changes and the level of fluctuating asymmetry in untreated beetles and in samples from the fifth and tenth generation. Exposure over ten generations led to an increase in the body size of the beetles, shortening of their pronotum and elongation of their thorax and abdomen. After ten generations of exposure to cypermethrin, FA levels decreased, indicating a canalization of development. This study provides new insights into the phenotypic markers of environmental pollution from agricultural activities. [ABSTRACT FROM AUTHOR]

The application of pesticides in agricultural activities can result in their runoff into water bodies, causing water contamination. This contamination poses a threat to water quality, rendering it harmful to aquatic organisms. This study investigated the acute toxic effects of the synthetic pyrethroid pesticide cypermethrin and the organophosphate pesticide chlorpyrifos, both individually and in combination, on the antioxidant enzyme activities viz., Xanthine oxidase (XOD), Superoxide dismutase (SOD) and Catalase (CAT) in the liver and gill tissues of the fish, Labeo rohita. L. rohita were exposed to sub-lethal concentrations of cypermethrin and chlorpyrifos individually and in combination for 7 days. The concentrations used were 1/10th of the LC50 dosage for individual treatments (0.308 µg/L for cypermethrin and 44.28 µg/L for chlorpyrifos) and 1/20th of the LC50 for the combined treatment (0.154µg/L for cypermethrin + 22.14µg/L for chlorpyrifos). The findings of this study revealed a significant (P<0.05) increase in the activities of Xanthine oxidase (XOD), Superoxide dismutase (SOD) and Catalase (CAT) in both liver and gill tissues compared to the control group. The observed alterations were more pronounced in the combined treatment as compared to individual exposures, suggesting a potential synergistic effect of cypermethrin and chlorpyrifos. [ABSTRACT FROM AUTHOR]

This study aimed to determine the levels of cypermethrin and hexachlorobenzene in milk and dairy products in Isfahan, Iran. In this study, 50 samples including raw milk, pasteurised milk, ultra-high temperature milk, traditional butter, pasteurised butter, traditional cheese, and pasteurised cheese were randomly collected from distribution centres in Isfahan city from June to September 2022. The pesticide levels in the samples were determined using high-performance liquid chromatography. The results indicated that the highest levels of cypermethrin, with 81.02 ± 23.77 µg/kg, were found in traditional butter, pasteurised butter, pasteurised cheese, and traditional cheese, which did not significantly differ. Regarding hexachlorobenzene, traditional butter with 66.68 ± 19.87 µg/kg and pasteurised butter with 47.16 ± 14.45 µg/kg had the highest contamination levels, which were not significantly different. The results indicated contamination of milk and dairy products supplied in Isfahan with pesticide residues. [ABSTRACT FROM AUTHOR]

Simple Summary: Houseflies (Musca domestica: Diptera) are serious medical and veterinary vectors of several human and animal pathogens. Ovicides reduce breeding housefly populations and the risk of housefly vector diseases. The natural ovicides of plant essential oils (EOs) and their main ingredients were suitable and sustainable options at this time against houseflies. This study evaluated the housefly ovicidal activities of four single-component formulations and two combination formulations of essential oils and their main constituents. The efficacy of each treatment was compared to that of α-cypermethrin (a synthetic insecticide). Two combinations: lemongrass (Cymbopogon citratus) EO + trans-anethole and star anise (Illicium verum) EO + geranial, were at least 1.1 times as effective in ovicidal activity as all single-component treatments and α-cypermethrin. They induced embryonic damage and mortality inside the activities of the eggs, disrupting the eggshell, hatching line, aeropyles, plastron, and micropyle. More significantly, the two combinations and all single-component formulations were safe for two non-target aquatic species: guppy (Poecilia reticulate: Poeciliidae) and molly (Poecilia latipinna: Poeciliidae), while α-cypermethrin was not safe for them. The two combinations could be developed into an effective and safe natural ovicide for reducing housefly populations and managing housefly vector diseases. This study attempted to evaluate the ovicidal activity of single-component formulations and combination formulations of lemongrass and star anise essential oils (EOs) and their main constituents against housefly eggs. The efficacies of the combinations were compared with those of single-component formulations and α-cypermethrin. Safety bioassays of all treatments and α-cypermethrin on non-target predators—guppy and molly—were conducted. Two combinations: 1% lemongrass EO + 1% trans-anethole and 1% star anise EO + 1% geranial, exhibited a strong ovicidal activity with an inhibition rate of 94.4 to 96.2%. They were 1.1 times as effective as α-cypermethrin. The two combinations also showed high synergistic activity compared to single-component formulations, with a high synergistic index and a high increased inhibition value of 37.4 to 57.7%. All EO treatments were benign for all non-target aquatic species with a high 50% lethal time (LT50) and safety index. In contrast, α-cypermethrin was highly toxic to them with a low LT50. The morphological abnormalities observed in housefly eggs at death were those such as the shrivelling of the eggs, aberrations and damage to the eggshells, hatching lines, aeropyles, plastron, and micropyle. The potential of these two combinations as a cypermethrin replacement is compelling. [ABSTRACT FROM AUTHOR]

Summary: While there are limited data on the environmental impact of administering equine parasiticide drugs, evidence from other species indicates significant negative ecological effects. Anthelmintic drugs are excreted unchanged or metabolised to other active and/or toxic metabolites that enter the environment through direct excretion. These chemicals can have significant toxic effects on insects, such as dung beetles, earthworms and aquatic animals. Of the frequently used equine anthelmintics, ivermectin is the most ecotoxic; available evidence indicates that moxidectin is less toxic and fenbendazole appears to have little impact on dung‐colonising insects but may be toxic to aquatic organisms and fungi. There are little data regarding the ecotoxicity of pyrantel and praziquantel, although their ecotoxic effects are thought to be low. Pasture hygiene reduces pharmaceutical contamination and also helps to break the endoparasitic cycle of infectivity, thus reducing reliance on anthelmintics. Judicious and targeted use of endoparasiticides, along with pasture hygiene measures, will limit the ecotoxic effects of these drugs as well as reduce the selection pressure that drives anthelmintic resistance. Anthelmintics may also negatively impact the equine gastrointestinal microbiota. Ectoparasiticides (such as fipronil, permethrin and cypermethrin) may also have significant negative ecological effects, with a risk of contamination of both the immediate environment and water courses following topical use of these drugs. The half‐life of fipronil in the environment is variable, but it degrades into compounds which are more toxic; for example, it is highly toxic to bees and is reported to bioaccumulate in fish and can be toxic to birds. Of the synthetic pyrethroids, permethrin degrades at a faster rate than cypermethrin and may therefore have a lower ecotoxic effect. The ecotoxic effects of injectable doramectin are likely to be similar to oral ivermectin, although persistence in faeces may be significantly prolonged compared to the oral treatment route for ivermectin. [ABSTRACT FROM AUTHOR]

This study examined the pattern of resistance to widely applied synthetic pyrethroids, i.e., cypermethrin and deltamethrin, against larvae of Rhipicephalus microplus ticks sampled from Marathwada region in Maharashtra, India. The study also examined the role of α- and β-esterases and glutathione-S-transferase (GST) in resistance development. All eight R. microplus isolates tested were resistant to deltamethrin (RL IV), having RR50 values from 6.88 to 131.26. LPT analysis exhibited the resistance level II deltamethrin resistance in Beed and Hingoli, III in Dharashiv, and IV in Sambhajinagar, Parbhani, Latur, Jalna, and Nanded isolates. The LIT analysis showed that Dharashiv field isolates had the lowest LC50 value of 229.09 ppm against cypermethrin, while Sambhajinagar field isolates had the highest at 489.78 ppm. The RR50 ranged from 1145.45 to 2448.9. Seven isolates were level I resistant to cypermethrin while the Jalna isolate was level II resistant. In larvae treated with deltamethrin and cypermethrin, the activity of α- and β-esterase enzymes increased significantly compared to control groups. The enzyme ratios in treated larvae ranged from 0.7533 to 1.7023 for α-esterase and 0.7434 to 3.2054 for β-esterase. The Hingoli isolate treated with cypermethrin exhibited the highest α-esterase activity (903.261), whereas Sambhajinagar isolate had the highest GST enzyme ratio (2.8224) after deltamethrin exposure. When exposed to cypermethrin, the Hingoli isolate showed the highest GST enzyme ratio, 2.0832. The present study provides the current resistance status in tick populations from Marathwada region indicating deltamethrin and cypermethrin to be ineffective for tick control. The results also suggest that SP compounds should be regulated in this region and alternative control strategies should be introduced. [ABSTRACT FROM AUTHOR]

The present study attempted to determine the acute toxicity and medial lethal concentrations of Cypermethrin (25% EC) for common carp Cyprinus carpio using Finney's static bioassay (1971), probit analysis method. The LC50 values for 24, 48, 72 and 96 hr were found to be 3.962 μl Lit-1, 3.767 μl Lit-1, 3.349 μl Lit-1 and 2.924 μl Lit-1 respectively. Fish (weight 90-100 g, length up to 18±2 cm) were exposed to different concentrations of cypermethrin which were 1.5 μl Lit-1, 2.0 μl Lit-1, 2.5 μl Lit-1, 3.0 μl Lit-1, 3.5 μl Lit-1, 4.0 μl Lit-1 and 4.5 μl Lit-1 up to 96 hr. LC50 value decreases with an increase in exposure time. During this exposure period, abnormal behaviors like restlessness, hyperactivity, erratic movements, increased opercular movements, and loss of equilibrium and response were noticed in carp. Over secretion of mucous all over the body surface along with respiratory stress and mortality was also observed. [ABSTRACT FROM AUTHOR]

The overuse of pesticides in agriculture poses significant threats to human health and the environment. This study addresses the issue by proposing a hybrid multi‐criteria decision‐making (MCDM) method, utilizing the analytic hierarchy process (AHP), to select the most suitable pesticide removal method for drinking water treatment. Focusing on the priority and selection of treatment options for specific pesticide groups, such as diuron and cypermethrin, based on toxicity and physicochemical properties, the study concludes that nanofiltration is best option for diuron removal, while granular activated carbon adsorption is effective for cypermethrin. The innovative hybrid MCDM (AHP + TOPSIS and AHP + VIKOR) approach, unprecedented in assessing pesticide removal methods for drinking water treatment, proves promising in ranking treatment processes for pesticides. The study emphasizes the serious consequences of excessive pesticide use, highlights treatment solutions like NF and GAC adsorption, and introduces cutting‐edge hybrid MCDM techniques for selection treatment process that meet technical, economical, and environmental requirements. All of these factors combine to provide a novel approach not only used to select the best option from alternatives, but also to prioritize alternative processes in drinking water treatment at pesticide removal practices. [ABSTRACT FROM AUTHOR]

Iron is widely linked with the onset and development of Parkinson's disease (PD). Accumulation of iron induces free radical generation and promotes α-synuclein aggregation, oxidative stress, and autophagy impairment. Deferoxamine, an iron chelator, is shown to ameliorate iron dyshomeostasis in rodents and humans. However, the role of deferoxamine in cypermethrin-induced iron accumulation is not yet known. Although an iron accumulation and impaired chaperone-mediated autophagy (CMA) contribute to PD, a link between the two is not yet widely understood. Current study is undertaken to explore the possible association between an iron accumulation and CMA in cypermethrin model of PD in the presence of deferoxamine. Level of iron, iron transporter proteins, oxidative stress, and CMA proteins along with indicators of Parkinsonism were measured. Deferoxamine attenuated cypermethrin-induced iron accumulation and number of iron-positive cells and ameliorated the demise of dopaminergic cells and dopamine content. Deferoxamine significantly normalizes cypermethrin-induced changes in iron transporter proteins, α-synuclein, lysosome-associated membrane protein-2A, and oxidative stress. The results demonstrate that deferoxamine ameliorates cypermethrin-induced iron dyshomeostasis and impairment in CMA. [ABSTRACT FROM AUTHOR]

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The aims of this study were to evaluate the exposure to permethrin and cypermethrin of young children aged between 2 and 5 years in Nakhon Pathom and Sing Buri provinces, Thailand. A questionnaire that included general demographic information, household characteristics, insecticide usage and exposure-related behavior in children was used to interview parents or family caregivers. Permethrin and cypermethrin concentrations on floor surfaces and children's hands, as well as their urinary metabolites, were analyzed by gas chromatography coupled with mass spectrometry. The results showed that permethrin and cypermethrin were detected in 62% and 83% of the children's hand wipe samples, with geometric mean (GM) levels of 0.02 µg and 0.04 µg, respectively. Permethrin and cypermethrin were detected in 79% and 93% of floor surface wipe samples, with GM levels of 0.90 µg/m2, and 1.49 µg/m2, respectively. For children's urine, the GM concentrations of cis- and trans-DCCA, 3-PBA, and total pyrethroid metabolites were 0.84, 0.31 and 1.23 nmol/g creatinine, respectively. This study found that household insecticide product usage and having a tile floor were associated with increased permethrin concentrations on the children's hands and floor surfaces. However, cypermethrin concentrations on floor surfaces were significantly higher in families using aerosol insecticide sprays and insecticide products in the living room and bedroom. The predictors of the total pyrethroid, DCCA and 3-PBA metabolites are permethrin on children's hands or floor surfaces and cypermethrin on floor surfaces. [ABSTRACT FROM AUTHOR]

Introduction: Houseflies serve as vectors of diseases in animals and humans. Chemical pesticides are a practical way of eliminating insects; however, resistance to insecticides has been reported. This study aims to evaluate the adulticidal efficacy of cypermethrin, tetramethrin, and piperonyl butoxide in housefly. Methods: Adult flies were cultured within net enclosures using completely randomized design with four replications each treatment. Treatment A was water and served as the negative control, treatment B was cypermethrin + tetramethrin + piperonyl butoxide 32% EC and served as the positive control, and treatment C was cypermethrin + tetramethrin + piperonyl butoxide 48% EC. The number of dead houseflies were counted 15, 30, 60, and 120 minutes post-application of treatments. The results were analyzed through analysis of variance (P≤0.05) followed by Tukey 's HSD (honestly significant difference). Results and Discussion: The values for the cumulative mean and percentage of killed houseflies were all significantly different from each other, with treatment C showing the highest values, followed by treatment B, then treatment A. The maximum adulticidal effect of treatment C was apparent within 15 minutes post-application, while the maximum adulticidal effect of treatment B was observed within 30 minutes after application. Conclusion: Results suggest that treatment C was a more effective adulticidal than other groups. Using cypermethrin + tetramethrin + piperonyl butoxide 48% EC can be the solution to the problem, but it should be noted that future resistance may occur. Increased concentrations may also imply environmental, human, and animal health hazards. [ABSTRACT FROM AUTHOR]

The experiment was conducted at the research plot of the Department of Entomology at Central Research Farm, Sam Higginbottom University of Agriculture Technology and Sciences, Prayagraj during the kharif season of 2023-24. The experiment was laid in Randomized Block Design with three replications. Eight treatments were evaluated against, Maruca vitrata viz., Bacillus thuringiensis (1 × 108 CFU/ml) @ 2 g/l, Neem oil @ 5 g/l, Spinosad 45 SC @ 0.2 ml/l, Emamectin Benzoate 5 SG @ 0.5 g/l, Cypermethrin 25 EC @ 2 ml/l, Beauveria bassiana (2 × 108 CFU/g) @ 4 g/l, Neem seed kernel extract 5% and Control. The lowest mean larval population of spotted pod borer was observed in Spinosad 45% SC @ 0.2 ml/l (0.95) followed by Emamectin Benzoate 5 SG @ 0.5 g/l (1.15), and Cypermethrin 25 EC @ 2 ml/l (1.33), which were on par with each other. The next best treatments included B. thuringiensis (1 × 108 CFU/ml) (1.47), B. bassiana (2 × 108 CFU/g) (1.60), Neem oil @ 5 g/l (1.75) and Neem seed kernel extract 5% (1.84). The higher yield and cost benefit ratio were recorded in Spinosad 45% SC @ 0.2 ml/l (32.94 q/ha, 1:2.99), Emamectin Benzoate 5 SG @ 0.5 g/l (31.88 q/ha, 1.2.82) and Cypermethrin 25 EC @ 2 ml/l (30.9 q/ha, 1:2.77) and were on par with each other. The next best treatments were B. thuringiensis (1 × 108 CFU/ml) (27.28 q/ha, 1:2.35) and B. bassiana (2 × 108 CFU/g) (25.64 q/ha, 1:2.14) which were on par with each other. Neem oil (24.08 q/ha, 1:1.84), Neem seed kernel extract 5% (23.4 q/ha, 1:1.77) recorded lowest yield and cost benefit ratio but were superior to control (17.0 q/ha, 1:1.20). [ABSTRACT FROM AUTHOR]

Cypermethrin, a synthetic pyrethroid, is a widely employed pesticide in large-scale commercial agriculture and domestic settings to control pests and boost crop yields. Despite its effectiveness in controlling pests, concerns persist about the potential ecological and human health impacts associated with its use. In the present study, the impact of cypermethrin on different parameters, including growth indices, pollen morphology and pollen fertility, chlorophyll and carotenoid content, hydrogen peroxide (H2O2) scavenging, lipid peroxidation (MDA concentration), superoxide dismutase (SOD), and catalase (CAT) activities, was investigated in Cicer arietinum L. The results showed that plants exhibited decreasing trends in plant height, number of branches, pods, and seeds per plant as cypermethrin concentrations increased. These changes resulted in significant reductions in the overall yield of the plants. The percentage of wrinkled pollen significantly increased with higher concentrations of cypermethrin and longer exposure durations. Exposure to cypermethrin showed significant variations in pollen fertility of C. arietinum at different concentrations and time intervals in comparison to control, which had a baseline pollen fertility of 79.12% ± 4.59. Chlorophyll and carotenoid content of C. arietinum were considerably affected by cypermethrin, indicative of potential disturbances in essential photosynthetic processes crucial for plant health. Further, with increasing concentrations of cypermethrin ranging from 100 mg/L to 500 mg/L, noticeable effects were observed on H2O2− scavenging, MDA concentration, SOD and CAT activities of C. arietinum in dose-dependent manner. Further, it was found that the duration of exposure and concentration of cypermethrin played a crucial role in exacerbating these detrimental effects. The findings of the present study raise concerns regarding the harmful effects of agricultural pesticides like cypermethrin and highlight the need for more research on the nutritional value of products derived from plants and seeds exposed to these agents.

This study evaluated pesticide exposure practices, and the potential health risks of drinking water and consuming fish from the cultivated wetlands of Ndop, Cameroon. Six hundred and twenty-six questionnaires were conveniently administered to farmers (≥ 26 years old) in a cross-sectional study to assess exposure practices and dietary risks. The Chi-square and Pearson correlation coefficients were used to establish relationships between variables. The PRIMET model was used to predict a worst-case dietary risk. The pesticide handling practices of 90% of farmers were inadequate. Chlorpyriphos, lambda-cyhalothrin, fipronil, and paraquat dichloride posed a possible dietary risk at recommended and applied doses, with chlorpyrifos having the highest exposure toxicity ratio (ETRdiet = 36.72). Paraquat dichloride, fipronil, and lambda-cyhalothrin posed a possible dietary risk at 26.3%, 58.3%, and 62.2% of their recommended concentrations, respectively. Remarkably, the dietary risk for cypermethrin was acceptable at 5.8 times its recommended dose (ETRdietR = 0.29). The significant positive correlation (p = 0.000) between PECfish and ETRdiet, suggests a possible health risk of consuming fish and drinking water harvested from the wetlands, thus the need for replacing pesticides posing possible risks at lower or recommended concentrations with less toxic alternatives and to train farmers on pesticide application practices. HIGHLIGHTS Most developing countries do not include dietary risk assessment in the pesticide authorization process because it is expensive.; The PRIMET model uses unsophisticated equipment to establish dietary risk in a worst-case scenario.; Many studies have explored the model to assess risk to aquatic life, terrestrial life, non-target organisms, and bees.; Limited data exist on its use in dietary risk assessment, and this research seeks to explore this.;

Black soldier fly larvae (Hermetia illucens) receive growing interest as a potential alternative animal feed source. These insects may be exposed to insecticide residues in the rearing substrate. This study aimed to investigate the effects of six different pyrethroid and organophosphate insecticides on this insect species' performance. The toxicity of two "model" substances for each of these classes (cypermethrin; pirimiphos‐methyl) was quantified, with and without the synergist piperonyl butoxide (PBO). Critical effect doses corresponding to 10% yield (CED10) for cypermethrin (0.4 mg/kg) and pirimiphos‐methyl (4.8 mg/kg) were determined. The addition of PBO to cypermethrin enhanced its relative potency with a factor 2.6. These data were compared against the relative toxicity of two analogue substances in each class (permethrin, deltamethrin; chlorpyrifos‐methyl, malathion). Results suggest that exposure to concentrations complying with legal limits can cause significant reductions in yield. Exposure to multiple substances at lower concentrations resulted in negative additive and synergistic effects. Of the tested substances, deltamethrin was most toxic, causing 94% yield at 0.5 mg/kg. Analytical results suggested that transfer of tested substances to the larval biomass was substance‐ and concentration‐specific, but appeared to be correlated to reduced yields and the presence of PBO. Transfer of organophosphates was overall low (<2%), but ranged from 8% to 75% for pyrethroids. Due to very low limits in insect biomass (∼0.01 mg/kg), high transfer may result in noncompliance. It is recommended that rearing companies implement lower contractual thresholds, and that policymakers consider adjusting legally allowed maximum residue levels in insect feed. [ABSTRACT FROM AUTHOR]

This study evaluated pesticide exposure practices, and the potential health risks of drinking water and consuming fish from the cultivated wetlands of Ndop, Cameroon. Six hundred and twenty-six questionnaires were conveniently administered to farmers (≥ 26 years old) in a cross-sectional study to assess exposure practices and dietary risks. The Chi-square and Pearson correlation coefficients were used to establish relationships between variables. The PRIMET model was used to predict a worst-case dietary risk. The pesticide handling practices of 90% of farmers were inadequate. Chlorpyriphos, lambda-cyhalothrin, fipronil, and paraquat dichloride posed a possible dietary risk at recommended and applied doses, with chlorpyrifos having the highest exposure toxicity ratio (ETRdiet = 36.72). Paraquat dichloride, fipronil, and lambda-cyhalothrin posed a possible dietary risk at 26.3%, 58.3%, and 62.2% of their recommended concentrations, respectively. Remarkably, the dietary risk for cypermethrin was acceptable at 5.8 times its recommended dose (ETRdietR = 0.29). The significant positive correlation (p = 0.000) between PECfish and ETRdiet, suggests a possible health risk of consuming fish and drinking water harvested from the wetlands, thus the need for replacing pesticides posing possible risks at lower or recommended concentrations with less toxic alternatives and to train farmers on pesticide application practices. [ABSTRACT FROM AUTHOR]

Zeugodacus cucurbitae Coquillett (Diptera: Tephritidae) is an agriculturally and economically important pest worldwide that has developed resistance to β‐cypermethrin. Glutathione S‐transferases (GSTs) have been reported to be involved in the detoxification of insecticides in insects. We have found that both ZcGSTd6 and ZcGSTd10 were up‐regulated by β‐cypermethrin induction in our previous study, so we aimed to explore their potential relationship with β‐cypermethrin tolerance in this study. The heterologous expression of ZcGSTd6 and ZcGSTd10 in Escherichia coli showed significantly high activities against 1‐chloro‐2,4‐dinitrobenzene (CDNB). The kinetic parameters of ZcGSTd6 and ZcGSTd10 were determined by Lineweaver–Burk. The Vmax and Km of ZcGSTd6 were 0.50 μmol/min·mg and 0.3 mM, respectively. The Vmax and Km of ZcGSTd10 were 1.82 μmol/min·mg and 0.53 mM. The 3D modelling and molecular docking results revealed that β‐cypermethrin exhibited a stronger bounding to the active site SER‐9 of ZcGSTd10. The sensitivity to β‐cypermethrin was significantly increased by 18.73% and 27.21%, respectively, after the knockdown of ZcGSTd6 and ZcGSTd10 by using RNA interference. In addition, the inhibition of CDNB at 50% (IC50) and the inhibition constants (Ki) of β‐cypermethrin against ZcGSTd10 were determined as 0.41 and 0.33 mM, respectively. The Ki and IC50 of β‐cypermethrin against ZcSGTd6 were not analysed. These results suggested that ZcGSTd10 could be an essential regulator involved in the tolerance of Z. cucurbitae to β‐cypermethrin. [ABSTRACT FROM AUTHOR]

Cypermethrin (CYP) is a synthetic pyrethroid insecticide, used in agriculture, and one of the most common contaminants in freshwater aquatic systems. This paper reports an evaluation of the toxicity of CYP in the mosquitofish, exposed to two concentrations (0.2 ng/L and 6.25 ng/L). The result revealed a significant modulation in the activity of antioxidants enzymes, superoxide dismutase, catalase and decreased acetylcholinesterase after 7 days. Hydrogen peroxide (H2O2) and malondialdehyde levels remained elevated throughout the exposure duration. CYP causes gills and liver oxidative stress, modifying the antioxidant enzymes. Principal component analysis highlighted relationship between biomarkers in functional response. These findings suggest that exposure to CYP can lead to various antioxidant processes in the fish gills and liver. [ABSTRACT FROM AUTHOR]

The occurrence of pesticide residues in animal products deserves attention because of the contamination by environmental pollutants and pesticides that may be present in the food that animals are fed. The goal of this work was the validation of a method for detection of residues of multiple classes of pesticide and determination of their residues in chicken breast fillets. Gas chromatography with mass spectrometry was used for analysis. A modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method was put into practice for its validation and applied to real samples. The study optimised mass detection and investigated the effect of a freezing step during the preparation of samples. Pesticides were determined in samples from conventional and organic production. The impact of the matrix effect decreased, with the largest number of pesticides and satisfactory recovery determined by the application of mixed solvent acetonitrile and ethyl acetate for extraction. Detection of pesticide residues was achieved in a linear range between 5 and 50 µg/kg with satisfactory excellent correlation coefficients greater than 0.99. The recovery of all the pesticide residues ranged between 71.2 and 118.80%. The relative standard deviation was from 2.9% to 18.1% for all validated pesticide residues. The limits of quantification were in the range of 3.0–4.9 µg/kg. Out of 56 pesticide residues analysed in real samples, 5 were detected: α endosulfan, cypermethrin, endosulfan sulphate, permethrin and p,p´-dichlorodiphenyltrichloroethane (DDT) and their concentrations ranged from 4.9 to 15.2 µg/kg. All tested samples were compliant with the evaluation criteria, and detected values of pesticide residues were lower than the maximum residual levels. [ABSTRACT FROM AUTHOR]

Background: "Regeneration time" (RT) denotes the time required to obtain a stable mortality rate for mosquitoes exposed to insecticide-treated nets (ITNs) after three consecutive washes of a net in a day. The RT informs the wash interval used to artificially age ITNs to simulate their lifetime performance under user conditions (20 washes). RT was estimated following World Health Organization (WHO) longitudinal method (LM) procedures. Longitudinal evaluation may introduce heterogeneity due to mosquito batch variability, complicating RT determination. To overcome this, nets at each stage of regeneration (i.e., 1, 2, 3, 5 and 7 days post wash) were prepared in advance and refrigerated; then, a complete regeneration series was tested with a single mosquito batch on 1 testing day, completing four series over 4 days. This study compared the complete series method (CSM) against the LM. Methods: The overall heterogeneity in the methods for estimating RT of one incorporated alpha-cypermethrin and piperonyl butoxide (PBO) and one incorporated permethrin with PBO ITNs was determined using laboratory-reared resistant Anopheles arabiensis under standard laboratory conditions. LM methods and CSM were compared in two experiments with refrigerated nets acclimated for (i) 2 h (test 1) and (ii) 3 h (test 2). Four regeneration replicates per day were tested per ITN product with 50 mosquitoes exposed per replicate (equivalent sample size to LM). The heterogeneity from these methods was compared descriptively. Results: The intra-method variability for unwashed pieces was minimal, with variance of 1.26 for CSM and 1.18 for LM. For unwashed nets, LM had substantially greater variance and ratio of LM:CSM was 2.66 in test 1 and 2.49 in test 2. The magnitude of mortality measured in bioassays depended on sample acclimation after refrigeration. Conclusions: The CSM is a convenient method for determining the regeneration times. ITNs are prepared in advance, reducing pressure to prepare all samples to start on a single day. A complete regeneration series of samples is removed from the refrigerator, defrosted and evaluated on a single day with one mosquito batch reducing the influence of mosquito batch heterogeneity on results. Replicates can be conducted over several days but do not have to be conducted on consecutive days, allowing easy facility scheduling. [ABSTRACT FROM AUTHOR]