Search

The appropriate use of human biomonitoring data to model population chemical exposures is challenging, especially for rapidly metabolized chemicals, such as agricultural chemicals. The objective of this study is to demonstrate a novel approach integrating model predicted dietary exposures and biomonitoring data to potentially inform regulatory risk assessments. We use lambda-cyhalothrin as a case study, and for the same representative U.S. population in the National Health and Nutrition Examination Survey (NHANES), an integrated exposure and pharmacokinetic model predicted exposures are calibrated to measurements of the urinary metabolite 3-phenoxybenzoic acid (3PBA), using an approximate Bayesian computing (ABC) methodology. We demonstrate that the correlation between modeled urinary 3PBA and the NHANES 3PBA measurements more than doubled as ABC thresholding narrowed the acceptable tolerance range for predicted versus observed urinary measurements. The median predicted urinary concentrations were closer to the median measured value using ABC than using current regulatory Monte Carlo methods.

This study examines the phenotypic differences between wild-derived F2 Central Valley mosquitoes and the insecticide-susceptible Rockefeller (Rock) lab strain of Ae. aegypti. Given the rarity of wild pyrethroid-susceptible populations, the focus of this work is to develop an understanding of the resistance physiology in this invasive mosquito population and explore the potential of metabolites as diagnostic biomarkers for metabolic resistance. This study utilizes metabolomic, gene expression, and lifespan data for a comparison between strains. The findings indicate that wild-derived mosquitoes with greater metabolic resistance have a lifespan sensitivity to restricted larval nutrition. In terms of metabolism and gene expression, Central Valley mosquitoes show increased activity in oxidoreductase, glutathione metabolism, and the pentose phosphate pathway. Conversely, Rock mosquitoes display signs of metabolic inefficiency and mitochondrial dysregulation, likely tolerated due to the consistency and nutritional abundance of a controlled lab environment. The study also examines Ae. aegypti P450 and GSTE profiles in relation to other insecticide-resistant groups. While metabolomic data can differentiate our study groups, the challenges in biomarker development arise from few detected markers meeting high fold change thresholds.

The toxicokinetics of lambda-cyhalothrin after single 20 mg kg(-1) oral and 3 mg kg(-1) intravenous doses were studied in rats. Serial blood samples were obtained after oral and intravenous administration. Liver, brain, spinal cord, sciatic nerve, vas deferens, anococcygeus and myenteric plexus tissue samples were also collected. Plasma, liver, hypothalamus, cerebellum, medulla oblongata, frontal cortex, striatum, hippocampus, midbrain, spinal cord, vas deferens, anococcygeus, myenteric plexus and sciatic nerve concentrations of lambda-cyhalothrin were determined by HPLC. The plasma and tissue concentration-time data for lambda-cyhalothrin were found to fit a two-compartment open model. For lambda-cyhalothrin, the elimination half-life (T1/2beta) and the mean residence time from plasma were 7.55 and 8.55 h after i.v. and 10.27 and 14.43 h after oral administration. The total plasma clearance was not influenced by dose concentration or route and reached a value of 0.060l h(-1)kg(-1). After i.v. administration, the apparent volume of distribution and at steady state were 0.68 and 0.53l kg(-1), suggesting a diffusion of the pyrethroid into tissue. After oral administration, lambda-cyhalothrin was extensively but slowly absorbed (Tmax, 2.69 h). The oral bioavailability was found to be 67.37%. Significant differences in the kinetic parameters between nervous tissues and plasma was observed. The maximum concentrations in hypothalamus (Cmax, 24.12 microg g(-1)) and myenteric plexus (Cmax, 25.12 microg g(-1)) were about 1.5 times higher than in plasma (Cmax, 15.65 microg ml(-1)) and 1.3 times higher than in liver (Cmax, 18.42 microg ml(-1)). Nervous tissue accumulation of lambda-cyhalothrin was also reflected by the area under the concentration curve ratios of tissue/plasma (liver). The T1/2beta for lambda-cyhalothrin was significantly greater for the nerve tissues, including neuromuscular fibres, (range 12-26 and 15-34 h, after i.v. and oral doses) than for plasma (7.55 an, Depto. de Farmacología y Toxicología, Fac. de Veterinaria, TRUE, pub

An experiment has been conducted to know the efficiency of some promising pyrethroids and bio-rational insecticides for controlling the major sucking pests of country beans under field conditions during the winter season September 2020 – March 2021. The different treatments were Cypermethrin 10 EC (T1), Lambda-Cyhalothrin 2.5 EC (T2), Emamectin benzoate 5 SG (T3), Abamectin 1.8 EC (T4), Spinosad 45 SC (T5), and untreated control (T6). The rate of leaf infestation at the lower, middle, and top stages of country bean ranged from 8.82–17.78, 13.89–36.39, and 13.72–33.33% in T5treated and untreated control plots, respectively. The rate of shoot infestation at the middle and top stages of country bean ranged from 18.67–34.33 and 17.00–39.27% in T5 treated and untreated control plots, individually. The lowest and highest inflorescence infestation of 29.15% and 46.67% was recorded in T5 treated and untreated control plots, separately.The lowest fruit infestation of 8.84% by number and 8.32% by weight was recorded in the treated plot T5. The rate of reduction of pod infestation over control was 48.58, 24.02, 23.39, 21.81, and 19.92% by number and 73.53, 61.76, 58.82, 52.94, and 41.18% by weight in the treated plot T5, T4, T1, T3, and T2, respectively. The yield in different treatments ranged from 1.35-2.50 t ha-1. The highest adjusted net return and BCR of Tk. 52220.00 and 2.42, respectively were obtained from T2 treated plots. The second highest BCR of 2.16 was calculated from T4 treated plot. The lowest BCR of 1.05 was found in T2 treated plot. The treatments T5, T4, and T3 were effective to suppress the major sucking pests of the country bean.

An experiment has been conducted to know the efficiency of some promising pyrethroids and bio-rational insecticides for controlling the major sucking pests of country beans under field conditions during the winter season September 2020 – March 2021. The different treatments were Cypermethrin 10 EC (T1), Lambda-Cyhalothrin 2.5 EC (T2), Emamectin benzoate 5 SG (T3), Abamectin 1.8 EC (T4), Spinosad 45 SC (T5), and untreated control (T6). The rate of leaf infestation at the lower, middle, and top stages of country bean ranged from 8.82–17.78, 13.89–36.39, and 13.72–33.33% in T5treated and untreated control plots, respectively. The rate of shoot infestation at the middle and top stages of country bean ranged from 18.67–34.33 and 17.00–39.27% in T5 treated and untreated control plots, individually. The lowest and highest inflorescence infestation of 29.15% and 46.67% was recorded in T5 treated and untreated control plots, separately.The lowest fruit infestation of 8.84% by number and 8.32% by weight was recorded in the treated plot T5. The rate of reduction of pod infestation over control was 48.58, 24.02, 23.39, 21.81, and 19.92% by number and 73.53, 61.76, 58.82, 52.94, and 41.18% by weight in the treated plot T5, T4, T1, T3, and T2, respectively. The yield in different treatments ranged from 1.35-2.50 t ha-1. The highest adjusted net return and BCR of Tk. 52220.00 and 2.42, respectively were obtained from T2 treated plots. The second highest BCR of 2.16 was calculated from T4 treated plot. The lowest BCR of 1.05 was found in T2 treated plot. The treatments T5, T4, and T3 were effective to suppress the major sucking pests of the country bean.

Current-use pesticides (CUP) are extensively applied in both agricultural and urban settings. Exposure occurs mainly via the dietary pathway; however, other pathways such as inhalation or skin contact are also important. In this study, urinary levels of 12 CUP metabolites were investigated among 110 parent-child pairs during two seasons of 2020. Metabolites of pyrethroids (3-PBA, t/c-DCCA), chlorpyrifos (TCPY), and tebuconazole (TEB-OH) were detected in more than 60% of the samples. Chlorpyrifos metabolite was found at the highest concentration and tebuconazole was detected in almost all samples. CUP urinary metabolite levels were significantly higher in children in comparison to adults, except for tebuconazole, which was similar in both groups. In children, winter samples had significantly higher concentrations of pyrethroid and chlorpyrifos metabolites in comparison to the summer samples, but in adults, only chlorpyrifos metabolite concentrations were higher in the winter. No association between CUP urinary metabolite levels and proximity/surface of agricultural areas around residences was observed. Based on our findings, we suspect that CUP exposure is mainly driven by diet and that the effect of environmental exposure is less significant. Daily Intakes were estimated with three possible scenarios considering the amount of the metabolite excreted in urine and were compared to Acceptable Daily Intake values. Using a realistic scenario, exposure to chlorpyrifos exhibited the highest health risk, but still within a safe level. The Acceptable Daily Intake was exceeded only in one child in the case of cypermethrin. The cumulative risk assessment of pesticide mixtures having an effect on the nervous system, based on the total margin of exposure calculations, did not indicate any risk. The overall risk associated with pesticide exposure in the observed population was low. However, the risk observed using the worst-case scenario suggests the need for continuous evaluatio

Little is known about personal and time-integrated exposure to past and current used pesticides in agricultural areas and within-family exposure similarities. We aimed to assess exposure to pesticides using silicone wristbands in child/guardian pairs living on farms and in villages within two agricultural areas in South Africa. Using silicone wristbands, we quantified 21 pesticides in child/guardian pairs in 38 households over six days in 2018. Levels (in ng/g wristband) of pesticides and their transformation products (12 current-use pesticides and nine organochlorine pesticides) were measured using GC–MS/MS. We assessed the correlation between pesticide levels and between household members using Spearman correlation coefficients (rs). Multivariable generalized least squares (GLS) models, using household id as intercept, were used to determine level of agreement between household members, exposure differences between children and guardians and exposure predictors (study area, household location [farm vs. village] and household pesticide use). We detected 16 pesticides with highest detection frequencies for deltamethrin (89%), chlorpyrifos (78%), boscalid (56%), cypermethrin (55%), and p,p′-DDT (48%). Most wristbands (92%) contained two or more pesticides (median seven (range one to 12)). Children had higher concentrations than guardians for four pesticides. Correlation between the pesticide levels were in most cases moderate (rs 0.30–0.68) and stronger in children than in guardians. Five pesticides showed moderate to strong correlation between household members, with the strongest correlation for boscalid (rs 0.84). Exposure differences between the two agricultural areas were observed for chlorpyrifos, diazinon, prothiofos, cypermethrin, boscalid, p,p′-DDT and p,p′-DDE and within areas for cypermethrin. We showed that for several pesticides children had higher exposure levels than guardians. The positive correlations observed for child/guard

Piretroidi su insekticidi, odnosno antiektoparazitici, koji se široko koriste u poljoprivredi, javnoj higijeni i veterinarskoj medicini. To su sintetički analozi prirodnih jedinjenja piretrina, od kojih su znatno efikasniji i stabilniji na svetlost. Piretroidi spadaju među najmanje toksične insekticide (antiektoparazitike), odnosno smatra se da su prilično bezbedni za sisavce i ptice. Bez obzira na to, treba istaći da su zabeleženi brojni slučajevi trovanja kod životinja (pre svega kućnih ljubimaca) širom sveta. Postoji različita osetljivost pojedinih životinjskih vrsta na piretroide. Goveda i ovce su manje osetljivi od drugih vrsta domaćih životinja, dok ribe i mačke spadaju među najosetljivije vrste., Pyrethroids are insecticides, i.e. antiectoparasitics, which are widely used in agriculture, public hygiene and veterinary medicine. These are synthetic analogues of natural pyrethrin compounds, of which they are much more efficient and stable to light. Pyrethroids are among the least toxic insecticides, i.e. they are considered to be quite safe for mammals and birds. Nevertheless, it should be noted that numerous cases of poisoning in animals (especially pets) have been reported around the world. There is a different sensitivity of some animal species to pyrethroids. Cattle and sheep are less sensitive than other species of domestic animals, while fish and cats are among the most sensitive species.

Piretrum je ekstrakt ili smeša prirodnih insekticida, poznatih pod imenom piretrini, koji se dobijaju ekstrakcijom iz cvetnih glavica jedne vrste hrizanteme (Chrisanthemum cinerariifolium treviranus). Piretroidi su sintetička jedinjenja, strukturni analozi prirodnih piretrina. Pored njihove insekticidne aktivnosti, poznato je da piretrini i piretroidi poseduju i repelentno delovanje. Međutim, molekularna osnova načina odbijanja insekata još uvek nije do kraja razjašnjena. Cilj ovog rada je upravo da se koliko-toliko razjasni mehanizam repelentnog delovanja piretruma i piretroida kod komaraca i drugih štetnih insekata koji napadaju poljoprivredne kulture., Pyrethrum is an extract or mixture of natural insecticides, known as pyrethrins, which are obtained by extraction from the flower heads of a species of chrysanthemum (Chrisanthemum cinerariifolium treviranus). Pyrethroids are synthetic compounds, structural analogues of natural pyrethrins. In addition to their insecticidal activity, pyrethrins and pyrethroids are known to have repellent effects. However, the molecular basis of insect repellent has not yet been fully elucidated. The aim of this paper is to clarify the mechanism of repellent action of pyrethrum and pyrethroids in mosquitoes and other harmful insects that attack agricultural crops

The occurrence and spread of insecticide resistance has had a negative effect on the efficacy of insecticide-based tools and is distributed worldwide, including the Greater Mekong Subregion (GMS). This study aims to determine the insecticide susceptibility of malaria and dengue vectors in malaria and dengue hotspots on the Thai-Myanmar border. Mosquito larvae and pupae were obtained from water sources from December 2019 to April 2020 in Tha Song Yang District, Tak province, western Thailand. WHO bioassay susceptibility tests were conducted with three classes of insecticides to evaluate the knockdown and mortality rates of Anopheles and Aedes aegypti female adults. V1016G and F1534C kdr mutations in the voltage-gated sodium channel of Ae. aegypti were identified using a multiplex PCR. A total of 5764 female mosquitoes were bioassayed in this study, including Anopheles spp. (92.63%) and F1 Ae. aegypti (7.37%). After 24 h of observation, An. minimus s.l. (n = 3885) and An. maculatus s.l. (n = 1138) in Suan Oi (SO) and Tala Oka (TO) were susceptible to pyrethroids, organophosphates and carbamates (except bendiocarb) with 98-100% mortality (MR). Resistance to bendiocarb was detected with a mortality rate of 88.80%, 88.77%, and 89.92% for An. minimus s.l. (n = 125, 125) and An. maculatus s.l. (n = 66), respectively. The first generation of Ae. aegypti adult females were suspected of resistance to deltamethrin (n = 225, MR = 96.89%) and confirmed resistance to permethrin (n = 200, MR = 20.00%). V1016G and F1534C mutations were detected in three genotypes, heterozygote and homozygote forms. The correlation between the kdr alleles and deltamethrin resistance was significant. In conclusion, bendiocarb resistance was found in primary malaria vectors, An. minimus s.l. and An. maculatus s.l. F1 Ae. aegypti population was pyrethroids-resistant, associated with kdr alleles. Therefore, molecular analysis should be conducted to gain insights into the mechanism of insecticide resista

BACKGROUND: Half the worlds population is at risk for malaria. Indoor residual spraying (IRS) with insecticides has been effective in controlling malaria, yet the potential neurotoxicity of these insecticides is of concern, particularly for infants exposed in utero. OBJECTIVES: To determine the association of prenatal exposure to DDT/DDE and pyrethroid insecticides and behavioral/emotional problems in two-year-old children. METHODS: The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) birth cohort in South Africa, measured concentrations of p,p-DDT and p,p-DDE in maternal serum and pyrethroid metabolites (cis-DBCA, cis-DCCA, trans-DCCA, and 3-PBA) in maternal urine collected during pregnancy. At 2 years, 683 mothers were interviewed about their childrens behavior and emotional development, using the Child Behavior Checklist (CBCL). We examined associations between behavioral or emotional problems and biomarkers of prenatal insecticide exposure. RESULTS: Maternal serum p,p-DDT concentrations were associated with heightened withdrawn behavior in 2-year olds, with a 0.24 increase in raw scores (95%CI = 0.00, 0.49) and a 12% increase (95%CI = 1.01, 1.23) in risk of being at or above the borderline-clinical level, per 10-fold increase in concentrations. Ten-fold increases in p,p-DDT and p,p-DDE were related to 30% (RR = 1.30; 95%CI = 1.01, 1.67) and 39% (RR = 1.39; 95%CI =1.01, 1.91) higher risks, respectively, for increased oppositional-defiant behavior. p,p-DDE concentrations were also related to increased risk of ADHD-related problems (RR = 1.30; 95%CI = 0.98, 1.72). Maternal urinary concentrations of cis-DBCA and 3-PBA were associated with increased risk of externalizing behaviors (RR = 1.30; 95%CI = 1.05, 1.62; RR = 1.35, 95%CI = 1.03, 1.78 per 10-fold increase, respectively), with some evidence of an association between cis-DB

Piretroidi su insekticidi, odnosno antiektoparazitici, koji se široko koriste u poljoprivredi, javnoj higijeni i veterinarskoj medicini. To su sintetički analozi prirodnih jedinjenja piretrina, od kojih su znatno efikasniji i stabilniji na svetlost. Piretroidi spadaju među najmanje toksične insekticide (antiektoparazitike), odnosno smatra se da su prilično bezbedni za sisavce i ptice. Bez obzira na to, treba istaći da su zabeleženi brojni slučajevi trovanja kod životinja (pre svega kućnih ljubimaca) širom sveta. Postoji različita osetljivost pojedinih životinjskih vrsta na piretroide. Goveda i ovce su manje osetljivi od drugih vrsta domaćih životinja, dok ribe i mačke spadaju među najosetljivije vrste., Pyrethroids are insecticides, i.e. antiectoparasitics, which are widely used in agriculture, public hygiene and veterinary medicine. These are synthetic analogues of natural pyrethrin compounds, of which they are much more efficient and stable to light. Pyrethroids are among the least toxic insecticides, i.e. they are considered to be quite safe for mammals and birds. Nevertheless, it should be noted that numerous cases of poisoning in animals (especially pets) have been reported around the world. There is a different sensitivity of some animal species to pyrethroids. Cattle and sheep are less sensitive than other species of domestic animals, while fish and cats are among the most sensitive species.

Piretrum je ekstrakt ili smeša prirodnih insekticida, poznatih pod imenom piretrini, koji se dobijaju ekstrakcijom iz cvetnih glavica jedne vrste hrizanteme (Chrisanthemum cinerariifolium treviranus). Piretroidi su sintetička jedinjenja, strukturni analozi prirodnih piretrina. Pored njihove insekticidne aktivnosti, poznato je da piretrini i piretroidi poseduju i repelentno delovanje. Međutim, molekularna osnova načina odbijanja insekata još uvek nije do kraja razjašnjena. Cilj ovog rada je upravo da se koliko-toliko razjasni mehanizam repelentnog delovanja piretruma i piretroida kod komaraca i drugih štetnih insekata koji napadaju poljoprivredne kulture., Pyrethrum is an extract or mixture of natural insecticides, known as pyrethrins, which are obtained by extraction from the flower heads of a species of chrysanthemum (Chrisanthemum cinerariifolium treviranus). Pyrethroids are synthetic compounds, structural analogues of natural pyrethrins. In addition to their insecticidal activity, pyrethrins and pyrethroids are known to have repellent effects. However, the molecular basis of insect repellent has not yet been fully elucidated. The aim of this paper is to clarify the mechanism of repellent action of pyrethrum and pyrethroids in mosquitoes and other harmful insects that attack agricultural crops

Organophosphate (OP) and pyrethroid pesticides (PYR) are extensively used in agriculture, resulting in higher exposures among farmworkers. The present study reports the occurrence of 8 urinary OP and PYR metabolites in a sample of farmworkers and residents from Sucs (n = 87), a rural township in North West Catalonia (Spain). The aim of the present study was to examine differences in urinary pesticide metabolite concentrations between occupationally-exposed (farmworkers; n = 45) and environmentally-exposed subjects (n = 42) and to assess the relationship between pesticide's exposures and occupational activities in a real-case scenario. Six OP and two PYR metabolites have been investigated, urine samples were extracted using SPE extraction and analyzed by UPLC-MS/MS. Three OP metabolites were commonly detectable in urine, namely TCPY (metabolite of chlorpyrifos), PNP (parathion) and DEAMPY (pirimiphos). Regarding pyrethroids, the two analyzed metabolites, 3-PBA and 4F-3-PBA, were detected in a high proportion of urine samples. Differences in concentrations between both groups were statistically significant for TCPY and 4F-3-PBA (Mann-Whitney U Test for independent groups, p < 0.05). In the case of TCPY, the concentrations were higher among the farmworkers, which is consistent with their occupational activity. The small differences found in DEAMPY, PNP, 3-PBA or even the significant higher concentrations of 4F-3-PBA among rural population suggest a general exposure to these compounds, even in those who do not carry an occupational activity. Specific personal protective equipment (PPE) among farmworkers, such as the use of gloves and mask during mixing, showed a decrease in the exposure levels, although the differences were not statistically significant. However, a positive association was found between the use of a cap during mixing (for PNP and 3-PBA) and during application (only for 3-PBA). However, this piece of cloth is mainly used for sun protection, and when not

Pyrethroids are a major insecticide class, suitable for biomonitoring in humans. Due to similarities in structure and metabolic pathways, urinary metabolites are common to various active substances. A tiered approach is proposed for risk assessment. Tier I was a conservative screening for overall pyrethroid exposure, based on phenoxybenzoic acid metabolites. Subsequently, probabilistic approaches and more specific metabolites were used for refining the risk estimates. Exposure was based on 95th percentiles from HBM4EU aligned studies (2014–2021) covering children in Belgium, Cyprus, France, Israel, Slovenia, and The Netherlands and adults in France, Germany, Israel, and Switzerland. In all children populations, the 95th percentiles for 3-phenoxybenzoic acid (3-PBA) exceeded the screening value. The probabilistic refinement quantified the risk level of the most exposed population (Belgium) at 2% or between 1–0.1% depending on the assumptions. In the substance specific assessments, the 95th percentiles of urinary concentrations in the aligned studies were well below the respective human biomonitoring guidance values (HBM-GVs). Both information sets were combined for refining the combined risk. Overall, the HBM data suggest a low health concern, at population level, related to pyrethroid exposure for the populations covered by the studies, even though a potential risk for highly exposed children cannot be completely excluded. The proposed tiered approach, including a screening step and several refinement options, seems to be a promising tool of scientific and regulatory value in future.

The blood-brain barrier (BBB) is a structural and functional interface between the plasma and the human brain. Predictive BBB in-vitro models like immortalized human capillary microvascular endothelial cells (HCMEC/D3) can be used to explore the BBB disruption potential of daily exposed chemicals. The present study was focused on investigating the human BBB permeation potential of one organophosphate pesticide, chlorpyrifos (CPF), and two pyrethroids, permethrin (PMT) and cyfluthrin (CFT). HCMEC/D3 cells were exposed to the chemical and the time-dependent pass across BBB along with permeation coefficient (Papp) was calculated. Transendothelial electrical resistance (TEER) was measured for the cells to check the monolayer formation and later to check the reduction in integrity after chemical exposure. Real time PCR was conducted to investigate the effect of chemicals on the expression BBB´s tight and adherens junction proteins. Calculated Papp value for three chemicals was in the following order: CPF>CFT>PMT, where CPF showed the highest permeation coefficient. TEER calculation showed that the integrity decreased after CPF exposure which was in concordance with Papp value whereas for other chemicals, no change in TEER after exposure was observed. In addition, the transwell study showed a higher efflux ratio (ER) (>2) of CFT indicating that CFT could be a substrate for active transport. For CPF and PMT, ER was less than 2, so no active transport seems to be involved. The evaluation of the mRNA expression analysis revealed a statistically significant decrease in Occludin (OCLN) gene expression for CPF, VE-Cadherin (CDH5) for PMT and Zonula Occludens (ZO1) expression for CFT. Our study showed that CPF has the highest potential for inducing cell death, higher permeation, and capability to induce BBB dysfunction than among the above-mentioned chemicals. Additionally, the results of the permeation study could be useful to build a human PBPK model using in vitro-to-in vivo

Little is known about personal and time-integrated exposure to past and current used pesticides in agricultural areas and within-family exposure similarities. We aimed to assess exposure to pesticides using silicone wristbands in child/guardian pairs living on farms and in villages within two agricultural areas in South Africa. Using silicone wristbands, we quantified 21 pesticides in child/guardian pairs in 38 households over six days in 2018. Levels (in ng/g wristband) of pesticides and their transformation products (12 current-use pesticides and nine organochlorine pesticides) were measured using GC–MS/MS. We assessed the correlation between pesticide levels and between household members using Spearman correlation coefficients (rs). Multivariable generalized least squares (GLS) models, using household id as intercept, were used to determine level of agreement between household members, exposure differences between children and guardians and exposure predictors (study area, household location [farm vs. village] and household pesticide use). We detected 16 pesticides with highest detection frequencies for deltamethrin (89%), chlorpyrifos (78%), boscalid (56%), cypermethrin (55%), and p,p′-DDT (48%). Most wristbands (92%) contained two or more pesticides (median seven (range one to 12)). Children had higher concentrations than guardians for four pesticides. Correlation between the pesticide levels were in most cases moderate (rs 0.30–0.68) and stronger in children than in guardians. Five pesticides showed moderate to strong correlation between household members, with the strongest correlation for boscalid (rs 0.84). Exposure differences between the two agricultural areas were observed for chlorpyrifos, diazinon, prothiofos, cypermethrin, boscalid, p,p′-DDT and p,p′-DDE and within areas for cypermethrin. We showed that for several pesticides children had higher exposure levels than guardians. The positive correlations observed for child/guardian pairs living in the s

Systemic insecticides are recognized as one of the drivers of the worldwide bee decline as they are exposed to them through multiple pathways. Specifically, neonicotinoids, some of which are banned for outdoor use in the European Union (EU), have been pointed out as a major cause of bee collapse. Thus, farmers have had to look for alternatives for pest control and use known insecticides or new substances reportedly less harmful to bees. We evaluated the oral acute toxicity of six insecticides (three of them systemic: imidacloprid, thiacloprid and sulfoxaflor) with four different modes of action on buff-tailed bumblebee workers (Bombus terrestris): two banned neonicotinoids (imidacloprid, thiacloprid), two pyrethroids (deltamethrin, esfenvalerate), one sulfoximine (sulfoxaflor) and a microbial insecticide based on Bacillus thuringiensis toxins, present in genetically modified (Bt) maize. The microbial insecticide only caused mortality to bumblebee workers at extremely high concentrations, so it is expected that Bt maize does not pose a risk to them. The toxicity of the other five insecticides on bumblebees was, from highest to lowest: imidacloprid, sulfoxaflor, deltamethrin, esfenvalerate and thiacloprid. This outcome suggests that certain insecticides in use are more toxic to B. terrestris than some banned neonicotinoids. Further chronic toxicity studies, under realistic conditions, are necessary for a proper risk assessment.

The blood-brain barrier (BBB) is a structural and functional interface between the plasma and the human brain. Predictive BBB in-vitro models like immortalized human capillary microvascular endothelial cells (HCMEC/D3) can be used to explore the BBB disruption potential of daily exposed chemicals. The present study was focused on investigating the human BBB permeation potential of one organophosphate pesticide, chlorpyrifos (CPF), and two pyrethroids, permethrin (PMT) and cyfluthrin (CFT). HCMEC/D3 cells were exposed to the chemical and the time-dependent pass across BBB along with permeation coefficient (Papp) was calculated. Transendothelial electrical resistance (TEER) was measured for the cells to check the monolayer formation and later to check the reduction in integrity after chemical exposure. Real time PCR was conducted to investigate the effect of chemicals on the expression BBB´s tight and adherens junction proteins. Calculated Papp value for three chemicals was in the following order: CPF>CFT>PMT, where CPF showed the highest permeation coefficient. TEER calculation showed that the integrity decreased after CPF exposure which was in concordance with Papp value whereas for other chemicals, no change in TEER after exposure was observed. In addition, the transwell study showed a higher efflux ratio (ER) (>2) of CFT indicating that CFT could be a substrate for active transport. For CPF and PMT, ER was less than 2, so no active transport seems to be involved. The evaluation of the mRNA expression analysis revealed a statistically significant decrease in Occludin (OCLN) gene expression for CPF, VE-Cadherin (CDH5) for PMT and Zonula Occludens (ZO1) expression for CFT. Our study showed that CPF has the highest potential for inducing cell death, higher permeation, and

Anthropogenic pollution is widespread across various ecosystems. This disturbance can alter the interaction between a host and its associated microbiome, with repercussions for hosts traits such as health, behavior, and host evolution. The thesis aim is to understand the effects of inert microplastics and other pollutants, as pesticides, detergents, and toxic metals, on the host-microbiota of different freshwater invertebrates. Specifically, this thesis explores the secondary effects of stress factors on the host, trophic interactions, and free-living microbes. Chapter I tested the effects of microplastics and the pesticide esfenvalerate on Chironomus riparius survival, emergence, and its microbiome. Chapter II tested the effects of microplastics and the pesticide deltamethrin on a trophic chain of three organisms: Daphnia magna, damselfly larva Ischnura elegans, and wild dragonfly larva Aeshna cyanea. Chapter III tested the effects of microplastics and sodium dodecyl sulfate on the microbiome of wild water boatman from the family Corixidae. Chapter IV tested the effects of microplastics and Chromium VI on Daphnia magna mortality and its microbiome. The thesis used metagenomic tools to characterize both the host microbiome and its surrounding microcosms. Our results showed that microplastics interact with additive toxicants to affect the host microbiome, however, these effects depend on the type of toxicant, the size of the microplastic, and the host itself., https://doi.org/10.33063/diva-442173

Anthropogenic pollution is widespread across various ecosystems. This disturbance can alter the interaction between a host and its associated microbiome, with repercussions for hosts traits such as health, behavior, and host evolution. The thesis aim is to understand the effects of inert microplastics and other pollutants, as pesticides, detergents, and toxic metals, on the host-microbiota of different freshwater invertebrates. Specifically, this thesis explores the secondary effects of stress factors on the host, trophic interactions, and free-living microbes. Chapter I tested the effects of microplastics and the pesticide esfenvalerate on Chironomus riparius survival, emergence, and its microbiome. Chapter II tested the effects of microplastics and the pesticide deltamethrin on a trophic chain of three organisms: Daphnia magna, damselfly larva Ischnura elegans, and wild dragonfly larva Aeshna cyanea. Chapter III tested the effects of microplastics and sodium dodecyl sulfate on the microbiome of wild water boatman from the family Corixidae. Chapter IV tested the effects of microplastics and Chromium VI on Daphnia magna mortality and its microbiome. The thesis used metagenomic tools to characterize both the host microbiome and its surrounding microcosms. Our results showed that microplastics interact with additive toxicants to affect the host microbiome, however, these effects depend on the type of toxicant, the size of the microplastic, and the host itself., https://doi.org/10.33063/diva-442173

Water treatment and reuse initiatives are essential to combat declining water supplies in a changing climate, especially in arid and semi-arid regions. Pollution of water resources intensifies the search for strategies to provide water for potable and non-potable reuse that mitigates detrimental ecological and human health effects. Fipronil and synthetic pyrethroids are common urban-use insecticides that exert aquatic toxicity at trace levels and have been often found in urban surface streams. In this study, samples were collected from the 182 ha Prado Wetlands in Southern California for seven months to assess the occurrence of fipronil and its degradation products as well as pyrethroids (bifenthrin and cyfluthrin) in water, sediment, and plants in a 4.45 ha vegetated surface flow constructed wetland (CW). Concentration-based removal values and changes in mass flux were calculated to determine the efficacy of CW treatment. Observed water concentrations were further used to calculate toxic units for the invertebrates Hyalella azteca and Chironomus dilutus. Pesticide concentrations in water, sediment, and plant samples consistently decreased during passage through the CW at all time points. Removal values for fipronil desulfinyl, fipronil sulfide, fipronil, fipronil sulfone, bifenthrin, and cyfluthrin were 100%, 99.7-100%, 57.8-88.1%, 75.6-100%, 74.7-100%, and 36.6-82.2%, respectively, and there was a general net deposition of pesticides into CW compartments. Toxic unit values decreased in every instance for both aquatic invertebrates. Settling of contaminated particles, adsorption to sediment, plant uptake or adsorption, and subsequent degradation contributed to the effective removal of these urban-use insecticides, which highlights the potential of CWs for protecting urban water quality.

Anthropogenic pollution is widespread across various ecosystems. This disturbance can alter the interaction between a host and its associated microbiome, with repercussions for hosts traits such as health, behavior, and host evolution. The thesis aim is to understand the effects of inert microplastics and other pollutants, as pesticides, detergents, and toxic metals, on the host-microbiota of different freshwater invertebrates. Specifically, this thesis explores the secondary effects of stress factors on the host, trophic interactions, and free-living microbes. Chapter I tested the effects of microplastics and the pesticide esfenvalerate on Chironomus riparius survival, emergence, and its microbiome. Chapter II tested the effects of microplastics and the pesticide deltamethrin on a trophic chain of three organisms: Daphnia magna, damselfly larva Ischnura elegans, and wild dragonfly larva Aeshna cyanea. Chapter III tested the effects of microplastics and sodium dodecyl sulfate on the microbiome of wild water boatman from the family Corixidae. Chapter IV tested the effects of microplastics and Chromium VI on Daphnia magna mortality and its microbiome. The thesis used metagenomic tools to characterize both the host microbiome and its surrounding microcosms. Our results showed that microplastics interact with additive toxicants to affect the host microbiome, however, these effects depend on the type of toxicant, the size of the microplastic, and the host itself., https://doi.org/10.33063/diva-442173

Triatominae (kissing bugs) are the vectors of Chagas disease. Chemical control of these insects is the main tool for reducing the incidence of the disease. Pyrethroids are the main insecticides used for triatomine control in all endemic countries. The evolution of insecticide resistance renders a successful chemical control strategy ineffective. In Argentina, different foci of resistance have been detected in Triatoma infestans—the most important vector in the Southern Cone of South America, which are associated with control deficiencies. The studies conducted on this species show that resistance is a complex problem because it has evolved in several areas of the species’ geographical distribution. Different resistance mechanisms have been identified. Resistance is associated with changes in various biological processes and linked to environmental changes. There is a lack of control alternatives. This paper is a review of the knowledge on pyrethroid resistance in T. infestans in Argentina., Los insectos triatominos son los vectores de la enfermedad de Chagas. El control químico de estos insectos es la principal herramienta utilizada para reducir la incidencia de la enfermedad. Los piretroides son los principales insecticidas utilizados para el control de los triatominos en todos los países endémicos. La evolución de resistencia a insecticidas convierte en ineficiente una exitosa estrategia de control químico. En Argentina se han detectado diferentes focos de resistencia en Triatoma infestans, el vector más importante en el Cono Sur de Sudamérica, asociados a deficiencias en el control. Los estudios realizados sobre esta especie muestran que la resistencia es un problema complejo, ya que evolucionó en varias zonas de la distribución geográfica de la especie, se identificaron diferentes mecanismos de resistencia, está asociada a modificaciones en diversos procesos biológicos, está vinculada a variaciones ambientales y hay escasez de alternativas de control. En este manuscrito presentamos una revisión del conocimiento sobre la resistencia a piretroides en T. infestans en Argentina., Os insetos triatomíneos são os vetores da doença de Chagas. O controlo químico desses insetos é a principal ferramenta utilizada para reduzir a incidência da doença. Os piretróides são os principais inseticidas usados para controlar os triatomíneos em todos os países endémicos. A evolução da resistência aos inseticidas converte em ineficiente uma estratégia de controlo químico eficiente. Na Argentina foram detetados diferentes focos de resistência em Triatoma infestans, o vetor mais importante do Cone Sul da América do Sul, associados a deficiências de controlo. Os estudos realizados nesta espécie mostram que a resistência é um problema complexo, visto que evoluiu em várias áreas da distribuição geográfica da espécie. Foram identificados diferentes mecanismos de resistência, associados a modificações em vários processos biológicos e ligados a variações ambientais, havendo uma escassez de alternativas de controlo. Neste manuscrito é apresentada uma revisão do conhecimento sobre a resistência aos piretróides em T. infestans na Argentina.

Anthropogenic pollution is widespread across various ecosystems. This disturbance can alter the interaction between a host and its associated microbiome, with repercussions for hosts traits such as health, behavior, and host evolution. The thesis aim is to understand the effects of inert microplastics and other pollutants, as pesticides, detergents, and toxic metals, on the host-microbiota of different freshwater invertebrates. Specifically, this thesis explores the secondary effects of stress factors on the host, trophic interactions, and free-living microbes. Chapter I tested the effects of microplastics and the pesticide esfenvalerate on Chironomus riparius survival, emergence, and its microbiome. Chapter II tested the effects of microplastics and the pesticide deltamethrin on a trophic chain of three organisms: Daphnia magna, damselfly larva Ischnura elegans, and wild dragonfly larva Aeshna cyanea. Chapter III tested the effects of microplastics and sodium dodecyl sulfate on the microbiome of wild water boatman from the family Corixidae. Chapter IV tested the effects of microplastics and Chromium VI on Daphnia magna mortality and its microbiome. The thesis used metagenomic tools to characterize both the host microbiome and its surrounding microcosms. Our results showed that microplastics interact with additive toxicants to affect the host microbiome, however, these effects depend on the type of toxicant, the size of the microplastic, and the host itself., https://doi.org/10.33063/diva-442173

The evolution of resistance to insecticides threatens the sustainable control of many of the world’s most damaging insect crop pests and disease vectors. To effectively combat resistance, it is important to understand its underlying genetic architecture, including the type and number of genetic variants affecting resistance and their interactions with each other and the environment. While significant progress has been made in characterizing the individual genes or mutations leading to resistance, our understanding of how genetic variants interact to influence its phenotypic expression remains poor. Here, we uncover a mechanism of insecticide resistance resulting from transposon-mediated insertional mutagenesis of a genetically dominant but insecticide-susceptible allele that enables the adaptive potential of a previously unavailable recessive resistance allele to be unlocked. Specifically, we identify clones of the aphid pest Myzus persicae that carry a resistant allele of the essential voltage-gated sodium channel (VGSC) gene with the recessive M918T and L1014F resistance mutations, in combination with an allele lacking these mutations but carrying a Mutator-like element transposon insertion that disrupts the coding sequence of the VGSC. This results in the down-regulation of the dominant susceptible allele and monoallelic expression of the recessive resistant allele, rendering the clones resistant to the insecticide bifenthrin. These findings are a powerful example of how transposable elements can provide a source of evolutionary potential that can be revealed by environmental and genetic perturbation, with applied implications for the control of highly damaging insect pests.

Anthropogenic pollution is widespread across various ecosystems. This disturbance can alter the interaction between a host and its associated microbiome, with repercussions for hosts traits such as health, behavior, and host evolution. The thesis aim is to understand the effects of inert microplastics and other pollutants, as pesticides, detergents, and toxic metals, on the host-microbiota of different freshwater invertebrates. Specifically, this thesis explores the secondary effects of stress factors on the host, trophic interactions, and free-living microbes. Chapter I tested the effects of microplastics and the pesticide esfenvalerate on Chironomus riparius survival, emergence, and its microbiome. Chapter II tested the effects of microplastics and the pesticide deltamethrin on a trophic chain of three organisms: Daphnia magna, damselfly larva Ischnura elegans, and wild dragonfly larva Aeshna cyanea. Chapter III tested the effects of microplastics and sodium dodecyl sulfate on the microbiome of wild water boatman from the family Corixidae. Chapter IV tested the effects of microplastics and Chromium VI on Daphnia magna mortality and its microbiome. The thesis used metagenomic tools to characterize both the host microbiome and its surrounding microcosms. Our results showed that microplastics interact with additive toxicants to affect the host microbiome, however, these effects depend on the type of toxicant, the size of the microplastic, and the host itself., https://doi.org/10.33063/diva-442173

Aedes aegypti, is a well-known vector of dengue, Chikungunya and Zika at the global level. Primary use of pyrethroids as control interventions has caused the development of a considerable level of immunity in Ae. aegypti. The current study assessed the efficacy of a pyrethroid, ?-cypermethrin on the survival and various life parameters of Ae. aegypti. The larvicidal studies with ?-cypermethrin revealed the respective LC50 and LC90 values as 0.26526 mg/L and 0.60211 mg/L. The impact of LC50 level was assessed on the growth and life attributes; such as gonotrophic cycle, egg development, hatchability, development and survival of immature stages, adult longevity, reproduction rate and generation time; of fourth instar of susceptible (S) and ?-cypermethrin-exposed population (E). The exposed population showed diminished fitness as compared to the susceptible population. The individual female fecundity in susceptible population was recorded as 79.6 with 61.6% hatchability rate as compared to the 28 eggs/female and 25% hatchability in the exposed population. The mean egg hatch time in S strain increased by 2-fold in E strain. The proportion of immature survival observed in S strain was 0.88 for fourth instar to pupa (P/I), 0.94 for pupa to adult (A/P) and an overall 0.83 for fourth larva to adult (A/I), which respectively reduced to 0.32, 0.86 and 0.27 in E strain of Ae. aegypti. Likewise, the net reproductive rate, birth rate and death rate were significantly (p < 0.05) higher in S than in E strain. This study demonstrates the negative impact of ?-cypermethrin on the physiological and reproductive fitness of Ae. aegypti.

In recent years, the worldwide prevalence of overweight and obesity among adults and children has dramatically increased. The conventional model regarding the onset of obesity is based on an imbalance between energy intake and expenditure. However, other possible environmental factors involved, such as the exposure to chemicals like pesticides, cannot be discarded. These compounds could act as endocrine-disrupting chemicals (EDC) that may interfere with hormone activity related to several mechanisms involved in body weight control. The main objective of this study was to systematically review the data provided in the scientific literature for a possible association between prenatal and postnatal exposure to pesticides and obesity in offspring. A total of 25 human and 9 animal studies were analyzed. The prenatal, perinatal, and postnatal exposure to organophosphate, organochlorine, pyrethroid, neonicotinoid, and carbamate, as well as a combined pesticide exposure was reviewed. This systematic review reveals that the effects of pesticide exposure on body weight are mostly inconclusive, finding conflicting results in both humans and experimental animals. The outcomes reviewed are dependent on many factors, including dosage and route of administration, species, sex, and treatment duration. More research is needed to effectively evaluate the impact of the combined effects of different pesticides on human health.

Pyrethroid pesticide exposures may be associated with the onset of depression in later life via disruption of dopaminergic, serotonergic, and neurological functioning. We sought to investigate the association between living near agricultural pyrethroid pesticide applications and depression measures in central California, using two waves (PEG 1&2, total N = 1,654) of a case control study of Parkinson's disease (PD). At enrollment, participants self-reported history of use of depression medications and dates of MD-diagnosed depression and anxiety. Participants also completed a Geriatric Depression Scale-Short Form upon enrollment. We used the California Pesticide Use Registry to assign estimated ambient pyrethroid pesticide exposures at participant's home addresses over the 5 years before the index date (date of outcome, or an age-matched year for participants without the outcome). We used logistic and linear regression to evaluate associations between living near any pyrethroid applications over the 5-year index period and measures of depression and anxiety. We also evaluated modification by study wave and PD status. We observed associations of pyrethroids with depression, depression medications, and anxiety (adjusted odds ratio [aOR] depression = 1.54, 95% confidence interval [CI] 1.14, 2.07; aOR depression medications = 1.68, 95% CI 1.25, 2.25; aOR anxiety = 1.60, 95% CI 1.17, 2.18). However, we observed no associations with mild/moderate depressive symptoms according to the GDS score at enrollment (aOR = 1.04, 95% CI 0.77, 1.42). We did not observe a consistent modification of the pyrethroid-depression associations by study wave and PD status. Ambient pyrethroid pesticide exposures may be associated with measures of depression in later life.

Pyrethroid pesticide exposures may be associated with the onset of depression in later life via disruption of dopaminergic, serotonergic, and neurological functioning. We sought to investigate the association between living near agricultural pyrethroid pesticide applications and depression measures in central California, using two waves (PEG 1&2, total N = 1,654) of a case control study of Parkinson's disease (PD). At enrollment, participants self-reported history of use of depression medications and dates of MD-diagnosed depression and anxiety. Participants also completed a Geriatric Depression Scale-Short Form upon enrollment. We used the California Pesticide Use Registry to assign estimated ambient pyrethroid pesticide exposures at participant's home addresses over the 5 years before the index date (date of outcome, or an age-matched year for participants without the outcome). We used logistic and linear regression to evaluate associations between living near any pyrethroid applications over the 5-year index period and measures of depression and anxiety. We also evaluated modification by study wave and PD status. We observed associations of pyrethroids with depression, depression medications, and anxiety (adjusted odds ratio [aOR] depression = 1.54, 95% confidence interval [CI] 1.14, 2.07; aOR depression medications = 1.68, 95% CI 1.25, 2.25; aOR anxiety = 1.60, 95% CI 1.17, 2.18). However, we observed no associations with mild/moderate depressive symptoms according to the GDS score at enrollment (aOR = 1.04, 95% CI 0.77, 1.42). We did not observe a consistent modification of the pyrethroid-depression associations by study wave and PD status. Ambient pyrethroid pesticide exposures may be associated with measures of depression in later life.

A novel ultrasensitive nanobody-based electrochemical immunoassay was prepared for assessing human exposure to pyrethroid insecticides. 3-Phenoxybenzoic acid (3-PBA) is a common human urinary metabolite for numerous pyrethroids, which broadly served as a biomarker for following the human exposure to this pesticide group. The 3-PBA detection was via a direct competition for binding to alkaline phosphatase-embedded nanobodies between free 3-PBA and a 3-PBA-bovine serum albumin conjugate covalently immobilized onto citric acid-decorated nylon nanofibers, which were incorporated on a screen-printed electrode (SPE). Electrochemical impedance spectroscopy (EIS) was utilized to support the advantage of the employment of nanofibrous membranes and the success of the immunosensor assembly. The coupling between the nanofiber and nanobody technologies provided an ultrasensitive and selective immunosensor for 3-PBA detection in the range of 0.8 to 1000 pg mL-1 with a detection limit of 0.64 pg mL-1. Moreover, when the test for 3-PBA was applied to real samples, the established immunosensor proved to be a viable alternative to the conventional methods for 3-PBA detection in human urine even without sample cleanup. It showed excellent properties and stability over time.

BackgroundPyrethroid pesticide use is increasing worldwide, although the full extent of associated health effects is unknown. An epigenome-wide association study (EWAS) with exploratory pathway analysis may help identify potential pyrethroid-related health effects.MethodsWe performed an exploratory EWAS of chronic ambient pyrethroid exposure using control participants' blood in the Parkinson's Environment and Genes Study in the Central Valley of California (N = 237). We estimated associations of living and working near agricultural pyrethroid pesticide applications in the past 5 years (binary) with site-specific differential methylation, and used a false discovery rate (FDR) cut off of 0.05 for significance. We controlled for age, sex, education, cell count, and an ancestral marker for Hispanic ethnicity. We normalized methylation values for Type I/II probe bias using Beta-Mixture Quantile (BMIQ) normalization, filtered out cross-reactive probes, and evaluated for remaining bias with Surrogate Variable Analysis (SVA). We also evaluated the effects of controlling for cell count and normalizing for Type I/II probe bias by comparing changes in effect estimates and p-values for the top hits across BMIQ and GenomeStudio normalization methods, and controlling for cell count. To facilitate broader interpretation, we annotated genes to the CpG sites and performed gene set overrepresentation analysis, using genes annotated to CpG sites that were associated with pyrethroids at a raw p < 0.05, and controlling for background representation of CpG sites on the chip. We did this for both a biological process context (Gene Ontology terms) using missMethyl, and a disease set context using WebGestalt. For these gene set overrepresentation analyses we also used an FDR cut off of 0.05 for significance of gene sets.ResultsAfter controlling for cell count and applying BMIQ normalization, 4 CpG sites were differentially methylated in relation to pyrethroid exposure

The present study reports one of the few cases in which organophosphate (OP) and pyrethroid (PYR) pesticide human exposure is evaluated in family contexts by the analysis of mother/child pair samples. Urinary concentrations of 6 organic metabolites of organophosphates and 2 pyrethroids were measured in mothers and their 7-to 8-year-old children (n = 168) in a general population from the central area of Slovenia. The results were adjusted for specific gravity and creatinine. The most abundant OP metabolite in children was 4-nitrophenol (PNP) (median 0.7 ng/ml) and in mothers (0.45 ng/ml), representing parathion exposure. 3-Phenoxibenzoic acid (3-PBA) (0.26 ng/ml), the general metabolite of pyrethroids, and 3,5,6-trichloro-2-pyridinol (TCPY) (0.16 ng/ml; chlorpyriphos) were the second most abundant compounds in children and mothers, respectively. The geometric mean specific gravity adjusted concentrations of OPs and PYRs were statistically significantly higher in children than in their mothers (between 3% and 24% higher), with the exception of TCPY (26% lower). All OP and PYR metabolites found in higher concentration in children showed significant positive correlations with the metabolite concentrations found in the mothers (p < 0.05 and 0.01), involving the fact that higher maternal concentrations were associated with higher children levels. These differential mother-children distributions and significant correlations were observed for the 2 types of pesticides studied, OPs and PYRs, which have different chemical properties. This agreement is consistent with the incorporation of the pesticides because of the general activities developed in the family context, instead of pesticide-dependent specific inputs. Comparison of the estimated daily intakes with the acceptable daily intakes of all detected metabolites revealed no significant risk of adverse health effects from exposure to these pesticides. © 2019 The Authors

Background: Malaria remains a major public health concern in the Democratic Republic of the Congo (DRC) and its control is affected by recurrent conflicts. Médecins Sans Frontières (MSF) initiated several studies to better understand the unprecedented incidence of malaria to effectively target and implement interventions in emergency settings. The current study evaluated the main vector species involved in malaria transmission and their resistance to insecticides, with the aim to propose the most effective tools and strategies for control of local malaria vectors. Methods: This study was performed in 52 households in Shamwana (Katanga, 2014), 168 households in Baraka (South Kivu, 2015) and 269 households in Kashuga (North Kivu, 2017). Anopheles vectors were collected and subjected to standardized Word Health Organization (WHO) and Center for Disease Control (CDC) insecticide susceptibility bioassays. Mosquito species determination was done using PCR and Plasmodium falciparum infection in mosquitoes was assessed by ELISA targeting circumsporozoite protein. Results: Of 3517 Anopheles spp. mosquitoes collected, Anopheles gambiae sensu lato (s.l.) (29.6%) and Anopheles funestus (69.1%) were the main malaria vectors. Plasmodium falciparum infection rates for An. gambiae s.l. were 1.0, 2.1 and 13.9% for Shamwana, Baraka and Kashuga, respectively. Anopheles funestus showed positivity rates of 1.6% in Shamwana and 4.4% in Baraka. No An. funestus were collected in Kashuga. Insecticide susceptibility tests showed resistance development towards pyrethroids in all locations. Exposure to bendiocarb, malathion and pirimiphos-methyl still resulted in high mosquito mortality. Conclusions: This is one of only few studies from these conflict areas in DRC to report insecticide resistance in local malaria vectors. The data suggest that current malaria prevention methods in these populations are only partially effective, and require additional tools and strategies. Importantly, the resu

Pyrethroid resistance is a significant threat to agricultural, urban and public health pest control activities. Because economic incentives for the production of novel active ingredients for the control of public health pests are lacking, this field is particularly affected by the potential failure of pyrethroid-based insecticides brought about by increasing pyrethroid resistance. As a result, innovative approaches are desperately needed to overcome insecticide resistance, particularly in mosquitoes that transmit deadly and debilitating pathogens. Numerous studies have demonstrated the potential of plant essential oils to enhance the efficacy of pyrethroids. The toxicity of pyrethroids combined with plant oils is significantly greater than the baseline toxicity of either oils or pyrethroids applied alone, which suggests there are synergistic interactions between components of these mixtures. The present study examined the potential of eight plant essential oils applied in one of two concentrations (1% and 5%) to enhance the toxicity of various pyrethroids (permethrin, natural pyrethrins, deltamethrin and β-cyfluthrin). The various plant essential oils enhanced the pyrethroids to differing degrees. The levels of enhancement provided by combinations of plant essential oils and pyrethroids in comparison with pyrethroids alone were calculated and synergistic outcomes characterized. Numerous plant essential oils significantly synergized a variety of pyrethroids; type I pyrethroids were synergized to a greater degree than type II pyrethroids. Eight plant essential oils significantly enhanced 24-h mortality rates provided by permethrin and six plant essential oils enhanced 24-h mortality rates obtained with natural pyrethrins. By contrast, only three plant essential plants significantly enhanced the toxicity of deltamethrin and β-cyfluthrin. Of the plant essential oils that enhanced the toxicity of these pyrethroids, some produced varying levels of synergism and antagonism

Chemical and toxicological testing in the Cache Slough complex (the slough) of the North Delta indicated the aquatic biota are exposed to a variety of wastewater-derived food additives, pharmaceuticals, and personal care products in highest concentration during dry periods, and many insecticides, herbicides and fungicides with peak concentrations after winter rains. The insecticide groups currently known to be of greatest toxicological concern are the pyrethroids and the fiproles (i.e., fipronil and its degradation products). After stormwater runoff enters the system via Ulatis Creek, both pesticide groups attained concentrations that posed a threat to aquatic life. When the commonly used testing species, Hyalella azteca, was placed in Cache Slough, toxicity — and, at times, near total mortality — was seen over at least an 8-km reach of Cache Slough that extended from the uppermost end almost to the junction with the Deep Water Ship Channel. Previous work over many years has shown similar results after other winter storms. However, when H. azteca that carried a mutation providing resistance to pyrethroid pesticides were also deployed in the slough, no ill effects were observed, which provided strong evidence that pyrethroids were responsible for toxicity to the non-resistant strain. Abundant resident H. azteca in Cache Slough carry any of four mutations that provide resistance to pyrethroids. They also carry a mutation that provides resistance to organophosphate pesticides, and likely carbamate pesticides as well. After many years of exposure, sensitive genotypes have been nearly eliminated from the system, and replaced by a population unaffected by many insecticides now in common use. We offer a variety of reasons why this shift to a population with mutant genotypes is of considerable concern, but also note that society has yet to fully consider the ecological and regulatory ramifications of the evolutionary attainment of pollutant resistance.

Pyrethroid resistance is a significant threat to agricultural, urban and public health pest control activities. Because economic incentives for the production of novel active ingredients for the control of public health pests are lacking, this field is particularly affected by the potential failure of pyrethroid-based insecticides brought about by increasing pyrethroid resistance. As a result, innovative approaches are desperately needed to overcome insecticide resistance, particularly in mosquitoes that transmit deadly and debilitating pathogens. Numerous studies have demonstrated the potential of plant essential oils to enhance the efficacy of pyrethroids. The toxicity of pyrethroids combined with plant oils is significantly greater than the baseline toxicity of either oils or pyrethroids applied alone, which suggests there are synergistic interactions between components of these mixtures. The present study examined the potential of eight plant essential oils applied in one of two concentrations (1% and 5%) to enhance the toxicity of various pyrethroids (permethrin, natural pyrethrins, deltamethrin and β-cyfluthrin). The various plant essential oils enhanced the pyrethroids to differing degrees. The levels of enhancement provided by combinations of plant essential oils and pyrethroids in comparison with pyrethroids alone were calculated and synergistic outcomes characterized. Numerous plant essential oils significantly synergized a variety of pyrethroids; type I pyrethroids were synergized to a greater degree than type II pyrethroids. Eight plant essential oils significantly enhanced 24-h mortality rates provided by permethrin and six plant essential oils enhanced 24-h mortality rates obtained with natural pyrethrins. By contrast, only three plant essential plants significantly enhanced the toxicity of deltamethrin and β-cyfluthrin. Of the plant essential oils that enhanced the toxicity of these pyrethroids, some produced varying levels of synergism and antagonism

Insecticidal residual effect and triatomine infestation rates in houses of a community fumigated with lambdcyhalothrin (Icon) are reported. No mortality was observed in 5th-instar Triatoma infestans nymphs in 72-hr exposure test on three different surfaces, one month after fumigation for a dose of 31.5 mg am/m2. However, during post-exposure observation a mortality of 60% was recorded for those insect exposed on sprayed woodboard. The results observed with mud-containing treated walls, were markedly poorer (0% of mortality). Twelve month after spraying 40% of mortality was observed on first-instar T. infestans nymphs in 72-hr exposure test on woodboard, but lower mortality rates were observed in mud-containing materials. When the effect of deltamethrin (109 mg ai/m2) and lambdcyhalothrin (94 mg ai/m2) was compared, the former did not appear to be superior at similar loads. Both have showed a mortality rate of 30% on 5th-instar T. infestans nymphs three months post-fumigation. The dose utilized in the field fumigation was enough to get a significant (p < 0.0001) control of triatomine domestic infestation, since it was sufficient to keep 95% of the houses uninfested throughout 21 months following treatment, when compared with baseline situation. A remarkable knock-down effect on adult and nymphs forms of the insect and a high in situ mortality were observed as a result of its application, even at very low doses.

This paper presents data on the dynamic of B. aeneus populations in winter oilseed rape in the downriver section of the Danube in Serbia, which were acquired by yellow water traps and a beating method. Their susceptibility to several insecticides of different classes (organophosphates, pyrethroids and neonicotinoids) (adult vial test and dipping test) was tested over two seasons (2009 and 2010). B. aeneus populations developing under the agroecological conditions that exist in Serbia were monitored to detect the moment of OSR infestation during its sensitive growth stages. Adults were counted, and the data revealed that they infest winter OSR crops during the stem elongation growth stage (BBCH 30-31), reaching a population peak at the green-yellow bud stage (BBCH 57-59), and exceeding the economic threshold, while the populations decreased substantially during the subsequent stage (BBCH 61-69). Laboratory test results did not confirm any changes in B. aeneus susceptibility/resistance to pyrethroid, organophosphate and neonicotinoid insecticides. Migration of B. aeneus populations was monitored as a way of developing predictive models for estimation of infestation severity and the timing of pest outbreaks under agroecological conditions existing in Serbia. As resistance to pyrethroids has been confirmed in B. aeneus populations in many European countries, their susceptibility will be further monitored.

Chemical and toxicological testing in the Cache Slough complex (the slough) of the North Delta indicated the aquatic biota are exposed to a variety of wastewater-derived food additives, pharmaceuticals, and personal care products in highest concentration during dry periods, and many insecticides, herbicides and fungicides with peak concentrations after winter rains. The insecticide groups currently known to be of greatest toxicological concern are the pyrethroids and the fiproles (i.e., fipronil and its degradation products). After stormwater runoff enters the system via Ulatis Creek, both pesticide groups attained concentrations that posed a threat to aquatic life. When the commonly used testing species, Hyalella azteca, was placed in Cache Slough, toxicity — and, at times, near total mortality — was seen over at least an 8-km reach of Cache Slough that extended from the uppermost end almost to the junction with the Deep Water Ship Channel. Previous work over many years has shown similar results after other winter storms. However, when H. azteca that carried a mutation providing resistance to pyrethroid pesticides were also deployed in the slough, no ill effects were observed, which provided strong evidence that pyrethroids were responsible for toxicity to the non-resistant strain. Abundant resident H. azteca in Cache Slough carry any of four mutations that provide resistance to pyrethroids. They also carry a mutation that provides resistance to organophosphate pesticides, and likely carbamate pesticides as well. After many years of exposure, sensitive genotypes have been nearly eliminated from the system, and replaced by a population unaffected by many insecticides now in common use. We offer a variety of reasons why this shift to a population with mutant genotypes is of considerable concern, but also note that society has yet to fully consider the ecological and regulatory ramifications of the evolutionary attainment of pollutant resistance.

Insecticidal residual effect and triatomine infestation rates in houses of a community fumigated with lambdcyhalothrin (Icon) are reported. No mortality was observed in 5th-instar Triatoma infestans nymphs in 72-hr exposure test on three different surfaces, one month after fumigation for a dose of 31.5 mg am/m2. However, during post-exposure observation a mortality of 60% was recorded for those insect exposed on sprayed woodboard. The results observed with mud-containing treated walls, were markedly poorer (0% of mortality). Twelve month after spraying 40% of mortality was observed on first-instar T. infestans nymphs in 72-hr exposure test on woodboard, but lower mortality rates were observed in mud-containing materials. When the effect of deltamethrin (109 mg ai/m2) and lambdcyhalothrin (94 mg ai/m2) was compared, the former did not appear to be superior at similar loads. Both have showed a mortality rate of 30% on 5th-instar T. infestans nymphs three months post-fumigation. The dose utilized in the field fumigation was enough to get a significant (p < 0.0001) control of triatomine domestic infestation, since it was sufficient to keep 95% of the houses uninfested throughout 21 months following treatment, when compared with baseline situation. A remarkable knock-down effect on adult and nymphs forms of the insect and a high in situ mortality were observed as a result of its application, even at very low doses.

Although effective in controlling malaria, indoor residual spraying results in elevated exposure to insecticides such as dichlorodiphenyltrichloroethane (DDT) and pyrethroids. These chemicals cross the placenta, but no studies have examined their associations with birth outcomes in populations residing in indoor residual spraying areas. We investigated this question in the Venda Health Examination of Mothers, Babies and Their Environment (VHEMBE), a birth cohort study of 751 South African children born between 2012 and 2013. We measured maternal peripartum serum DDT and urine pyrethroid metabolite concentrations and collected data on birth weight, length, head circumference, and duration of gestation. We analyzed the data using marginal structural models with inverse-probability-of-treatment weights, generalized propensity scores, and standard conditional linear regression. Using all 3 analytical methods, p,p'-DDT, o,p'-DDT, and to a lesser extent p,p'-dichlorodiphenyldichloroethylene were related to elevated birth weight, birth length, and head circumference among girls. Changes in gestational duration did not mediate this relationship, suggesting that these exposures accelerate fetal growth, which is consistent with the known estrogenic properties of o,p'-DDT and p,p'-DDT. No associations with pyrethroid metabolites were found. Results suggest that prenatal exposure to DDT is related to elevated birth size. Further studies are needed to elucidate the implications of these findings.

Urinary metabolites of organophosphate (OP) and pyrethroid (PYR) pesticides from seven years old children of a birth cohort study (n=199; PHIME cohort of Trieste, Italy) have been measured. Six OP and two PYR metabolites have been investigated, 2-diethylamino-6-methylpyrimidin-4-ol (DEAMPY, pirimiphos metabolite) was the one found at higher concentrations, median 3.4 ng/mL specific gravity adjusted (SG adjusted), followed by 4-nitrophenol (PNP, median 1.4 ng/mL SG adjusted) and 3,5,6-trichloro-2-pyridinol (TCPY, median 0.36 ng/mL SG adjusted), parathion and chlorpyriphos metabolites, respectively. TCPY concentrations were low in comparison to other distributions of OP metabolites in children from other studies. Accordingly, the PHIME cohort showed a distinct OP metabolite distribution with high concentrations of pirimiphos and parathion. Another specific characteristic of this cohort was the high concentration of 3-phenoxybenzoic acid (3-BPA, median 0.36 ng/mL SG adjusted), a general metabolite of PYR pesticides. Evaluation of anthropometric and socio-demographic characteristics of children and families only showed a positive association between family educational level and urinary concentrations of DEAMPY metabolite (p<0.05), which could reflect distinct dietary habits depending on the educational level. Estimated daily intakes were evaluated, all studied metabolites were found within safe levels. © 2019 Elsevier Inc.

A general overview of insecticide resistance mechanisms in stored product and urban pests is given. The most important cases of metabolic and target site resistance are discussed and recent discoveries about the resistance mechanisms to phosphine in Coleoptera are presented.

Anthropogenic contaminants are considered to play a substantial role in the decline of freshwater invertebrate diversity. Sub-lethal effects of many of these contaminants on behaviour and life-history traits of aquatic invertebrates may contribute to their decline. As contaminants are rarely present in the environment alone, the effects of mixture exposures are highly relevant in assessing the risk these substances pose to the biota. This thesis focuses on sub-lethal effects of exposure to aquatic pollutants, separately and in combination, on fresh-water invertebrates. To investigate the single and combined effects of pesticides, larvae of the midge, Chironomus riparius were exposed to a 1 hour pulse of two neonicotinoids and two pyrethroids. This short exposure to environmentally relevant concentrations of pesticides decreased the survival and delayed development in C. riparius. The combination of neonicotinoids and pyrethroids did not produce synergistic effects; however, there was some indication of antagonism. Additionally, larvae of the damselfly, Coenagrion puella, were exposed for 14 hours to two environmentally relevant concentrations of pyrethroid pesticides, alone and in combination. Exposure to the pyrethroid, deltamethrin, reduced the larvae’s predatory ability. Combined exposure to both deltamethrin and esfenvalerate inhibited the Glutathione S-transferase detoxification pathway and may have additive toxic effects on the larvae’s predatory ability. Microplastics are increasingly gaining attention as an aquatic pollutant of major concern with respect to the toxicity of the microplastics themselves as well as their capacity to adsorb persistent organic pollutants like pesticides. To investigate the effects of microplastics and a pyrethroid, alone and in combination, C. riparius larvae were raised in sediment spiked with two sizes of polystyrene-based latex microbeads and an environmentally relevant concentration of esfenvalerate under normal and food-re

Anthropogenic contaminants are considered to play a substantial role in the decline of freshwater invertebrate diversity. Sub-lethal effects of many of these contaminants on behaviour and life-history traits of aquatic invertebrates may contribute to their decline. As contaminants are rarely present in the environment alone, the effects of mixture exposures are highly relevant in assessing the risk these substances pose to the biota. This thesis focuses on sub-lethal effects of exposure to aquatic pollutants, separately and in combination, on fresh-water invertebrates. To investigate the single and combined effects of pesticides, larvae of the midge, Chironomus riparius were exposed to a 1 hour pulse of two neonicotinoids and two pyrethroids. This short exposure to environmentally relevant concentrations of pesticides decreased the survival and delayed development in C. riparius. The combination of neonicotinoids and pyrethroids did not produce synergistic effects; however, there was some indication of antagonism. Additionally, larvae of the damselfly, Coenagrion puella, were exposed for 14 hours to two environmentally relevant concentrations of pyrethroid pesticides, alone and in combination. Exposure to the pyrethroid, deltamethrin, reduced the larvae’s predatory ability. Combined exposure to both deltamethrin and esfenvalerate inhibited the Glutathione S-transferase detoxification pathway and may have additive toxic effects on the larvae’s predatory ability. Microplastics are increasingly gaining attention as an aquatic pollutant of major concern with respect to the toxicity of the microplastics themselves as well as their capacity to adsorb persistent organic pollutants like pesticides. To investigate the effects of microplastics and a pyrethroid, alone and in combination, C. riparius larvae were raised in sediment spiked with two sizes of polystyrene-based latex microbeads and an environmentally relevant concentration of esfenvalerate under normal and food-re

Insecticides, such as pyrethroids, have frequently been detected in runoff from urban areas, and their offsite transport can cause aquatic toxicity in urban streams and estuaries. To better understand the wash-off process of pesticide residues in urban runoff, the association of pyrethroids with sediment in runoff from residential surfaces was investigated in two watersheds located in Northern California (Sacramento County). Rainfall, flow rate, and event mean concentrations/loads of sediments and pyrethroids, collected during seasonal monitoring campaigns from 2007 to 2014, were analyzed to identify relationships among stormwater quality and rainfall characteristics, primarily using Principal Component Analysis (PCA). Pyrethroid wash-off was strongly related to sediment wash-off whenever sediment loads exceeded 10 mg; this value was conveniently selected as a threshold between dissolved and particle-bound control of off-site pyrethroid transport. A new mechanistic model for predicting pyrethroid wash-off profiles from residential surfaces at basin-scale was implemented in the Storm Water Management Model (SWMM). The accuracy of the model predictions was estimated by evaluating the root mean square error (RMSE), Nash⁻Sutcliff efficiency (NSE), and Kling⁻Gupta efficiency (KGE) for each pyrethroid detected (RMSEtot = 0.13; NSEtot = 0.28; KGEtot = 0.56). The importance of particle-bound transport revealed in this work confirms previous field investigations at a smaller scale, and it should be a key consideration when developing policies to mitigate pesticide runoff from urban areas.

Insecticides, such as pyrethroids, have frequently been detected in runoff from urban areas, and their offsite transport can cause aquatic toxicity in urban streams and estuaries. To better understand the wash-off process of pesticide residues in urban runoff, the association of pyrethroids with sediment in runoff from residential surfaces was investigated in two watersheds located in Northern California (Sacramento County). Rainfall, flow rate, and event mean concentrations/loads of sediments and pyrethroids, collected during seasonal monitoring campaigns from 2007 to 2014, were analyzed to identify relationships among stormwater quality and rainfall characteristics, primarily using Principal Component Analysis (PCA). Pyrethroid wash-off was strongly related to sediment wash-off whenever sediment loads exceeded 10 mg; this value was conveniently selected as a threshold between dissolved and particle-bound control of off-site pyrethroid transport. A new mechanistic model for predicting pyrethroid wash-off profiles from residential surfaces at basin-scale was implemented in the Storm Water Management Model (SWMM). The accuracy of the model predictions was estimated by evaluating the root mean square error (RMSE), Nash⁻Sutcliff efficiency (NSE), and Kling⁻Gupta efficiency (KGE) for each pyrethroid detected (RMSEtot = 0.13; NSEtot = 0.28; KGEtot = 0.56). The importance of particle-bound transport revealed in this work confirms previous field investigations at a smaller scale, and it should be a key consideration when developing policies to mitigate pesticide runoff from urban areas.

Anthropogenic contaminants are considered to play a substantial role in the decline of freshwater invertebrate diversity. Sub-lethal effects of many of these contaminants on behaviour and life-history traits of aquatic invertebrates may contribute to their decline. As contaminants are rarely present in the environment alone, the effects of mixture exposures are highly relevant in assessing the risk these substances pose to the biota. This thesis focuses on sub-lethal effects of exposure to aquatic pollutants, separately and in combination, on fresh-water invertebrates. To investigate the single and combined effects of pesticides, larvae of the midge, Chironomus riparius were exposed to a 1 hour pulse of two neonicotinoids and two pyrethroids. This short exposure to environmentally relevant concentrations of pesticides decreased the survival and delayed development in C. riparius. The combination of neonicotinoids and pyrethroids did not produce synergistic effects; however, there was some indication of antagonism. Additionally, larvae of the damselfly, Coenagrion puella, were exposed for 14 hours to two environmentally relevant concentrations of pyrethroid pesticides, alone and in combination. Exposure to the pyrethroid, deltamethrin, reduced the larvae’s predatory ability. Combined exposure to both deltamethrin and esfenvalerate inhibited the Glutathione S-transferase detoxification pathway and may have additive toxic effects on the larvae’s predatory ability. Microplastics are increasingly gaining attention as an aquatic pollutant of major concern with respect to the toxicity of the microplastics themselves as well as their capacity to adsorb persistent organic pollutants like pesticides. To investigate the effects of microplastics and a pyrethroid, alone and in combination, C. riparius larvae were raised in sediment spiked with two sizes of polystyrene-based latex microbeads and an environmentally relevant concentration of esfenvalerate under normal and food-re